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Article

Analysis of Hotspots in the Field of Sulfonamides Treatment: A Bibliometric Review

by
Jian Wang
1,2,
Xinyao Liu
1,3,
Feng Qian
1,2,* and
Jie Su
1,2,*
1
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
2
Institute of Water Eco-Environment Research, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
3
College of Water Sciences, Beijing Normal University, Beijing 100875, China
*
Authors to whom correspondence should be addressed.
Water 2025, 17(12), 1792; https://doi.org/10.3390/w17121792
Submission received: 1 May 2025 / Revised: 6 June 2025 / Accepted: 10 June 2025 / Published: 15 June 2025
(This article belongs to the Section Wastewater Treatment and Reuse)
Browse Figures
Versions Notes

Abstract

:
Sulfonamide drugs (SAs) are a class of emerging contaminants widely present in water environments, which has gradually attracted attention from scholars worldwide. Based on the Web of Science core collection database, this study employs bibliometric methods and visualization tools, such as CiteSpace, Bibliometrix, and VOSviewer, to systematically analyze the literature on the treatment of SAs from 2004 to 2024, exploring the research status, hotspots, and development trends in this field. The results indicate that research on SAs in the past 20 years can be categorized into three stages: initial exploration (2004–2008), slow development (2009–2016), and in-depth research (2017–2024), with an overall increasing trend in number of publications. China and the United States have published the most articles on SAs, with 2266 and 592 articles respectively, and the collaborative ties between the two countries are the strongest. The Chinese Academy of Sciences is the most prolific institution, having published 348 articles. Science of the Total Environment is the journal with the highest publication volume. Among the many SAs, sulfamethoxazole has garnered the greatest research interest, and its primary entry route into the water environment is through the discharge of sewage treatment plants. The research focus has gradually shifted from the source analysis of SAs in the environment to seeking efficient methods for removing SAs. Future research should prioritize investigations into antibiotic-resistant bacteria and antibiotic resistance genes associated with SAs.

1. Introduction

In recent years, global production of antibiotics has remained high. Due to incomplete metabolism by humans and animals, over 30% of antibiotics are released into the environment, leading to contaminated water bodies [1,2]. Sulfonamides (SAs) are one of the earliest effective antibiotics applied clinically. Due to their low cost and broad-spectrum antibacterial ability, they have been widely applied in livestock and aquaculture as well as in the control of human and animal diseases [3,4]. SAs are widely detected with varying levels of residues in water environments worldwide, with concentrations ranging from ng/L to mg/L in wastewater treatment plants, groundwater and surface water.
SAs are present in the aqueous environment in a variety of forms, with varying toxicity, chemical properties and degradation performance. Among them, Sulfamethoxazole (SMX) has received the highest attention, but the existing treatment processes in most wastewater treatment plants do not achieve satisfactory removal of SAs. Some SAs remain in trace amounts in water environments, which are difficult to biodegrade and pose a certain degree of harm to aquatic organisms and human health [5,6]. Most seriously, the discharge of SAs into water bodies through various routes has led to the production of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs), reducing their role in disease prevention and treatment [7,8].
As the environmental problems caused by the pollution of SAs become more and more prominent, the research around SAs continues to increase at home and abroad. This study adopts a bibliometric approach to systematically analyze SAs-related research during the period 2004–2024. While quantitatively analyzing the relevant literature, we analyze the research hotspots and development frontiers in this field with the help of software and bibliometric platforms, such as CiteSpace, Bibliometrix and VOSviewer. It is expected to provide technical support for the in-depth study of SAs and environmental management.

2. Data Sources and Analysis Methods

2.1. Data Sources

SCI-E articles were retrieved in the field of SAs processing based on the Core database of Web of Science (WOS) from Clarivate Analytics. For the period 2004–2024, a topic search was conducted with TS = (sulfonamide* OR sulfamethoxazole OR sulfamethazine OR sulfathiazole OR sulfadiazine OR sulfamethizole OR sulfachloropyridazine OR sulfamerazine OR sulfamethoxypyridazine OR sulfamonomethoxine OR sulfisoxazole) AND (wastewater* OR “wastewater*” OR waste-water OR sewage OR effluent* OR river OR lake OR sea OR wetland OR “surface water*” OR “ground water*”) AND (remov* OR degrad* OR treat* OR adsor* OR pollut* OR contaminat*) as the subject term, and the document type “Article” was selected. A total of 4878 documents were searched for SAs in the field of water treatment, with a search date of 7 March 2024.

2.2. Analysis Methods

This study mainly adopted bibliometric analysis methods and utilized software tools, such as CiteSpace 6.1.R6 [9], VOSviewer 1.6.20 [10], Biblioshiny (https://www.bibliometrix.org/home/index.php/layout/biblioshiny, accessed on 10 June 2025) [11] and bibliometric (https://bibliometric.com) online analysis platform software, for scientific metrological analysis. It compares the research status and trends in the field of SAs in the past 20 years and explores the research hotspots and future directions in the field.
CiteSpace is a Java-based citation network analysis tool first introduced in 2004 by Professor Chaomei Chen of Drexel University. It is mainly used for measuring, analyzing, identifying and displaying new trends in the development of scientific literature data with accuracy, simplicity and efficiency.
VOSviewer is a visualization software developed by Leiden University in the Netherlands, which offers unique advantages in clustering techniques, mapping and other aspects. Biblioshiny is a program based on the R language Bibliometrix installer run by Dr. Massimo Aria, Associate Professor at the Department of Economics and Statistics, University of Naples Federico II, Italy, and others. The bibliometric online analysis platform software is an easy-to-use and user-friendly literature visualization tool that provides valuable reference information for researchers.

3. Research Status Analysis

3.1. The Number of Published Papers and Its Changing Trend

The trend in the number of publications in the SAs treatment research area in WoS over the years is shown in Figure 1. The research on SAs has been increasing in popularity over the last 20 years, with an overall upward trend in the number of articles published globally. The overall research is divided into three phases: (I) 2004–2008 was the initial research exploration phase; the SAs treatment field received little attention, and the annual number of publications was less than 50. (II) 2009–2016 was the slow development phase; the annual number of publications showed a rapid growth trend, but the annual number of publications was still less than 200. (III) 2017–2024 was the in-depth research phase; the number of publications showed a rapid growth trend, and the number of publications in eight years accounted for 79% of the total number of publications, which indicates that the environmental problems caused by SAs are of wide concern. From 2004 to 2016, the total number of articles published by domestic scholars was less than 300. However, with the release of the “Water Ten Plan” in 2015 [12] and the “New Pollutant Management Action Programme” issued by the General Office of the State Council in 2024, and the gradual exposure of water pollution caused by SAs in the process of urban development, research in this field has increased and the number of publications has been on a rapid increase. In 2024, the annual number of publications in China has reached 451, accounting for 65% of the total number of publications worldwide in that year, indicating that both the importance and the number of results of SAs treatment research by domestic scholars are increasing.

3.2. Analysis of Issuing Country and Cooperation

From 2004 to 2024, a total of 106 countries worldwide published articles related to the treatment of SAs, of which the top 10 countries in terms of number of articles published are shown in Table 1. As can be seen, China ranked first in the world in terms of the number of articles published in that period, with 2266 articles, accounting for 46.5% of the total number of articles. The United States ranked second in the total number of articles published, with 592 articles, accounting for 12.1% of the total number of articles. All other countries have published less than 500 articles. In terms of citation frequency, China has the highest total citation frequency of 77,363, but a relatively low average citation frequency of 39.03. The US has the second-highest total citation frequency of 41,944, but the first-highest average citation frequency of 72.94. The H-index (H-index) refers to the number of times a person has had at most H papers cited at least H times each and can be applied to countries in the same way, with a higher H-index indicating that the country is more influential in the field [13]. China ranks first with an H-index of 133, the United States is second, and Spain, Germany and Canada all have H-indexes above 50.
Cooperation and exchange between countries is important for the dissemination of knowledge. The bibliometric online analysis platform software was used to analyze inter-country cooperation between the main publishers to capture the cooperation between different countries in the field of SAs research. The network of academic collaborative relationships between the 100 issuing countries from 2004 to 2024 is shown in Figure 2. The connected lines indicate that countries have collaborative relationships with each other, and the size of the shaded area indicates how many articles are issued by that country. As can be seen, the largest number of publications and the most extensive collaborative relationships are with China, which has collaborative relationships with dozens of countries, including the USA, Spain, Germany, Portugal and Canada, and has the closest collaborative relationship with the USA. The close cross-section of cooperation between countries indicates that the environmental problems caused by SAs are of common concern on a global scale.

3.3. Analysis of Issuing Institution

During the period 2004–2024, eight institutions published more than 90 articles in the field of SAs processing, six of which were from China (Table 2). The Chinese Academy of Sciences has 348 publications in this field, with a total citation frequency of 18,614 and an H-index of 77, which is much higher than other institutions. This is followed by Tsinghua University, Harbin Institute of Technology and the University of Chinese Academy of Sciences, indicating that China is highly active in the development of applications of SAs processing research and plays an important role in the field. The Spanish Higher Council of Sciences, in fifth place, has a high average citation frequency of 79.39 and an H-index of 50, despite only 109 publications during this period, indicating that the research results of this institution are of high practical application and academic influence, and have made a positive contribution to the research and development of the field. The active investment and continuous output of universities and research institutions worldwide in this field have brought new opportunities and challenges for the development and application of the field and provided new ideas and directions for future research.

3.4. Keyword-Based Bibliometrics Analysis

3.4.1. Topic Analysis: Analysis of Hot Journals, Published Countries and High-Frequency Keywords

When exploring hotspots on research topics, keywords in the literature need to be analyzed. After processing by the Biblioshiny program, the Sankey diagram between the top 15 hot source journals (left), countries of publication (center) and high-frequency keywords (right) in the SAs processing research area is shown in Figure 3. As can be seen, the hot journals are concentrated in Science of the Total Environment, Chemosphere and Chemical Engineering Journal. As the country with the highest number of publications, our papers were concentrated in the journals Science of the Total Environment and Chemical Engineering Journal, with high-frequency keywords, such as antibiotics, SMX, adsorption and antibiotic resistance genes. This indicates that SAs are frequently detected in wastewater and that the attention of Chinese scholars on SAs is mainly focused on drugs, such as SMX. Among the environmental problems caused by different types of SAs, the contamination of antibiotic resistance genes has received the most attention. At the same time, among the treatment methods based on SAs, adsorption has been chosen for the removal of SAs, but there are some new techniques applied for the removal of SAs.

3.4.2. Co-Occurrence Analysis: Co-Occurrence Network Diagram Analysis of SAs in Wastewater

In CiteSpace, we conducted the analysis using 2-year time slices spanning from 2000 to 2024. The parameters were configured with thresholds set at the top N = 20 items per slice, a minimum co-occurrence frequency of 5, and a betweenness centrality ≥0.1 to identify key nodes. A visual analysis of the co-occurrence of keywords appearing in the 4878 articles retrieved showed that 22 keywords were appearing more than 300 times. Figure 4 shows the co-occurrence network diagram for the keywords, where the size of the circles in the diagram reflects the frequency of the keywords, the higher the frequency, the larger the circles [14]. The size of the keyword node label represents the mediated centrality of the keyword, and in CiteSpace, nodes with a mediated centrality of more than 0.1 are considered critical nodes. The line between the nodes represents the co-occurrence of keywords; the thicker the line, the greater the frequency of co-occurrence. As can be seen in the graph, the keywords that appear more than 1000 times are “wastewater”, “removal” and “pharmaceutical”, indicating that SAs are an important class of antibiotics that enter the environment mainly through wastewater discharge. The keywords that appeared more than 500 times were “degradation”, “personal care products”, “sulfamethoxazole”, “antibiotics”, “treatment plant”, “wastewater treatment” and “surface water”. This indicates that SMX in SAs is a key pharmaceutical of concern; residual antibiotics and personal care products in wastewater treatment plants are a major source of SAs in the aqueous environment and have received increasing attention, while in recent years the research focus has gradually shifted to the search for efficient methods to remove SAs. The analysis of the keywords will help to gain an in-depth understanding of the transport and transformation behavior of SAs in the environment and their potential impact on the water environment, providing a valuable reference for the development of effective control and management strategies.

3.4.3. Cluster Analysis: Classification Analysis of SAs Research Topics in Wastewater

To further explore the research hotspots of SAs, VOSviewer 1.6.20 software was used to cluster the main keywords, and keywords with similar research topics were clustered and represented by the same color. The results are shown in Figure 5. The default LLR (Log-Likelihood Ratio) algorithm was employed to automatically generate cluster labels based on the keyword co-occurrence network. The keywords for SAs were divided into three main categories through cluster analysis. Cluster 1 focuses on the treatment methods for SAs, including advanced oxidation, adsorption, ozone oxidation, biodegradation and photocatalysis, etc. The keywords for Cluster 2 are mainly Sulfonamides resistance genes, and SAs entering environmental water bodies will induce resistant microorganisms and ARGs in the environment, accelerating the migration transformation, and posing a threat to the water environment and human health. The keywords in Cluster 3 focus on sources of contamination in water and testing techniques. As can be seen from this category, studies on contaminants in water mainly include pharmaceuticals, personal care products, methamphetamine pyrimethamine and lidocaine, which are often detected in sewage treatment plants, aquatic environments, surface water and groundwater. Water sampling techniques mainly include solid phase extraction and mass spectrometry. In addition, risk assessment of SAs has been a topical issue in the field of water environmental protection in recent years. Of these three categories, SAs treatment methods have received the most attention, indicating that scholars from various countries have conducted research and achieved important results on the residues of SAs, their toxicity in the environment and their biodegradation in different treatment processes and environments.

3.4.4. Hot Spot Analysis: The Keywords of SAs Hot Spot Analysis over Time in Wastewater

Keyword hotspot maps provide a visual representation of the evolution of research hotspots over time. The analysis of the occurrence time of the co-occurring keywords in Figure 6a revealed that mass spectrometry, tandem mass spectrometry and solid phase extraction were the hot spots of research before 2015, during which the pre-treatment method of samples mostly used solid phase extraction, and for the analysis of SAs, mass spectrometry and tandem mass spectrometry were mainly used. However, over time, the new keywords, such as aquatic environment, personal care products, sulfanilamide, biodegradation and wastewater treatment, started to emerge in 2016–2018, and it can be seen that biodegradation became the main treatment method in this period and that the problems caused by SAs and personal care products are gaining more attention from researchers due to their increasingly prominent impact in the aquatic environment. Until 2018, the terms sulfamethoxazole, degradation, adsorption, sulfamethoxazole, oxidation, photocatalytic oxidation and resistance genes appeared more and more frequently. This indicates that researchers are beginning to turn to research on the application of treatment technologies for SAs in the aqueous environment, with adsorption and advanced oxidation techniques, such as ozone catalysis, and photocatalysis gradually becoming hot technologies for the treatment of SAs. Among these, SMX and sulfamerazine (SMR) in SAs have become important pollutants of interest for research. As the research hotspots on SAs change, subsequent efforts should focus on developing more efficient treatment technologies for SAs.
According to the heat map of keywords over time shown in Figure 6b, the top ten ranked keywords did not appear very frequently during the period 2002–2009. However, from 2010 onwards, both “wastewater” and “pharmaceuticals” appear more than 100 times, indicating that the issue of wastewater and pharmaceutical discharges is gradually becoming a concern. Until 2012, the frequency of “antibiotics”, “sewage treatment plants” and “surface water” also exceeded 100 times, indicating that concerns about the presence of antibiotics in the environment and environmental issues, such as sewage treatment and surface water pollution, have been increasing over time. By 2020, with “wastewater”, “removal”, “pharmaceuticals”, “degradation” and “personal care products” all appearing more than 500 times, there is growing interest in the environmental impact of personal actions, such as the release of personal care products and drugs, as well as research into the impact of antibiotics and other drugs in the environment and how they degrade. In 2022, “wastewater”, “removal” and “pharmaceuticals” appear more than 1000 times, and the frequency of these keywords is expected to continue to increase after 2002 as the problem of SAs pollution becomes more acute.

4. Discussion

4.1. Types and Toxicity of SAs

SAs are a class of synthetic broad-spectrum antibiotics, one of the largest antibiotics produced, used and sold in China, and were formally used in clinical practice in 1935 [15]. The commonly used SAs are derivatives with the basic structure of para-aminobenzene sulfonamide, where hydrogen on the sulfonamide group is replaced by different groups to form different types of sulfonamide antibiotics, mainly including sulfamethoxazole (SMX), sulfadiazine (SDZ), sulfamerazine (SMR), sulfathiazole (STZ), sulfamethoxyridazine (SMP) and sulfamonomethoxine (SMM), the basic properties of which are shown in Table 3 [16]. Acidity coefficients were obtained from the iBond database [17] and the acute toxicity (LD50) and bioconcentration were calculated by the T.E.S.T 5.1.1.0 software. T.E.S.T (Toxicity Estimation Software Tool) was developed by the U.S. Environmental Protection Agency (EPA) and is based on the analysis of known QSAR (Quantitative Structure–Activity Relationship) models or literature to obtain the toxicity of compounds [18]. To assess the toxicity of different SAs, their acute toxicity and Bioconcentration factor (BAF) were predicted by the T.E.S.T toxicity assessment software. The LD50 of the sulfonamides listed in Table 3 all ranged from 1 to 3 mg/kg, with SMX and STZ having the lowest LD50 of 1.47 mg/kg. In addition, for the Sas, the bioaccumulation factors were all less than 1.5, with SMX having the largest bioaccumulation factor of 1.23.

4.2. Source of SAs in Water Environment

As can be seen from the metrological analysis of the keywords mentioned above, SAs are frequently detected in domestic and international wastewater treatment plants, and their types and influent and effluent concentrations are shown in Table 4. The common SAs are SMX, SDZ, SMR and SMM. Among them, SMX has high inlet and outlet water concentrations in the USA, ranging from 650 to 4255 ng/L and 86 to 4145 ng/L, respectively [19]. In China, SMX was also detected at relatively high concentrations, above 400 ng/L, and even up to 1000 ng/L in Guangdong, suggesting that China should focus on the study of the attribution analysis and removal technology of SMX in wastewater treatment plants in the future [20]. SDZ was detected at concentrations as high as 1240 ng/L in Spain, but below 250 ng/L in areas, such as Guangdong and Dalian in China [21], suggesting that the large variation in SAs concentrations in different regions is mainly due to the use of SAs in different regions and different removal rates in different wastewater treatment plants. In terms of the effluent concentrations of various SAs, most pollutants also have high detectable concentrations. In response to the residual situation of SAs in wastewater, more and more treatment processes are being applied to the wastewater treatment process for the purpose of removing SAs. However, most SAs are often not treated satisfactorily in wastewater treatment plants, and the removal rate of SAs in municipal wastewater treatment plants is only between 4% and 22%, resulting in a large number of residues entering natural water bodies and causing potential hazards [22,23].
In addition to wastewater treatment plants, SAs have been detected in environmental waters, such as urban sewage, surface water and groundwater, in several countries at concentrations ranging from ng/L to μg/L [3]. Tang et al. [24] detected eight SAs in the surface waters of the Nanjing section of the Yangtze River, with total concentrations ranging from 13.2 to 21 ng/L. The highest concentration was SMX, ranging from 6.76 to 8.98 ng/L, followed by SDZ, ranging from 2.52 to 6.59 ng/L. Comparative studies with other water bodies in the country and abroad have found that SAs in the basin are overall at a low level. Ma et al. [24] studied the characteristics of 29 antibiotics detected in Harbin groundwater and found that SAs accounted for 61.5% of the total, with levels ranging from 0.02 to 612 ng/L, with STZ, SDZ and lincomycin detected at the highest concentration of over 100 ng/L. Research on the removal of SAs from water is particularly important in the face of the potential risks they pose to human health and the ecological environment.
Table 4. Residues of sulfonamides in sewage treatment plants.
Table 4. Residues of sulfonamides in sewage treatment plants.
Survey RegionConstituentInfluent Concentration (ng/L)Effluent Concentration
(ng/L)		Ref
SpainSMX260160[25]
SDZ49.1~12408.75~286[21]
STZ7.31~1420.7~73
SMR2.13~7.370.205~1.93
Republic of KoreaSMX49~41047~397[26]
Beijing, ChinaSMX290~1000130~460[27]
SPD110~47036~330
SMZ8.8~117.8~10
Guangdong, ChinaSDZ15.44.12[20]
SMZ19.39.3
SMX405106
SMM5.6nd *
SPD39.616.3
SMX290~1000130~460
SPD110~47036~330
SMZ8.8~117.8~10
USASMX650~425586~4145[2]
UKSMX20~2744~44[28]
Dalian, ChinaSDZnd~212.7nd~150.4[29]
SMX4.3~8503.2~780.9
STZnd~4.1nd~2.4
SMRnd~3.8nd~0.4
SMMnd~13.4nd~3.3
Note: * Below the method quantitative limit.

4.3. Advances in Water Treatment Technology Based on Sulfonamides

In recent years, for SAs, water treatment technology is mainly divided into biological treatment technology, physical separation technology and advanced oxidation processes [30,31,32]. Comparing the application of commonly used technologies, it was found that advanced oxidation technologies accounted for the highest number of publications at 36%, followed by biological treatment technologies and physical separation technologies at 33% and 31%, respectively (Figure 7a). The advanced oxidation processes (AOPs) can also be divided into ozone oxidation, electrochemical technology, photocatalytic oxidation and persulfate oxidation [33,34,35]. Also, in Figure 7b, a trend of increasing numbers of publications on SAs water treatment technologies was found year-on-year between 2004 and 2024. It is worth noting that although AOPs started later, their publication volume has increased sharply since 2018 and continues to rise, accounting for a higher percentage each year. Among them, research on persulfate oxidation technology has also started to gradually increase, and in the past two years, the number of publications has even surpassed that of ozone oxidation technology and photocatalytic oxidation technology, occupying the main position. This phenomenon is probably due to the significant advantages of persulfate oxidation technology in the treatment of SAs.
Although biological removal is one of the mainstream treatment technologies for SAs, biological methods are influenced by the environment and cannot maximize the degradation potential of the degrading bacteria in the system, and the contribution of different degradation pathways to the degradation of SAs is unclear [36]. Further enhanced removal is required, with enhanced means, including adsorption, membrane separation and AOPs. Among them, physical removal techniques, such as adsorption and membrane separation, are only transfer of pollutant phases and cannot achieve the degradation and removal of SAs. This is hampered by the varying prices of adsorbents and the tendency of membrane systems to cause blockages and contamination.
AOPs is a technology that completely decomposes organic pollutants into small molecules of low or no toxicity by means of hydroxyl radicals (·OH) with the application of energy or catalysts. Several AOPs are based on ·OH to oxidatively decompose SAs in water, except for persulfate oxidation, which produces sulfate radicals (SO4·−). Yin et al. [37] synthesized reduced graphene oxides (rGO) and graphene oxides doped with nitrogen and phosphorus atoms (NGO and PGO) to study their catalytic efficiency for the O3 oxidation of SMX. The results showed that the NGOs and PGO had strong catalytic activity because the introduction of nitrogen and phosphorus atoms into the graphene oxide layer disrupted the sp2-hybridized carbon structure and provided new active sites for the O3 oxidation reaction. Compared with the degradation efficiency of O3 oxidation alone of 62%, the removal efficiency of O3 oxidation of SMX catalyzed by NGO and PGO as catalysts were as high as 95% and 99%, respectively. Tan et al. [38] prepared MoS2-xOx nanosheet precursors by adding oxygen to MoS2 for the activation of a H2O2 assisted co-catalytic Fenton system for oxidative degradation of SMX. DFT (Density Functional Theory) calculations demonstrated that oxygen doping could increase the electrical conductivity of MoS2-xOx and accelerate charge transfer, thus further activating H2O2. Wen et al. [39] investigated the degradation of SM2 by the vacuum UV photo-Fenton (VPF) method using a microjet vacuum UV reactor system. Compared with the conventional UV photo-Fenton method, the VPF method significantly enhanced the degradation and mineralization efficiency of SM2 due to the UV radiation that photolyzed H2O and accelerated the redox regeneration of Fe3+/Fe2+, generating more reactive oxygen species (ROS). Rajasekhar et al. [40] prepared a bimetallic oxide-activated carbon particle electrode (GAC-Co-Mn) by impregnation and degraded SAs with a three-dimensional electrocatalytic oxidation system composed of an electrocatalytic reaction cell. The bimetallic particle GAC-Co-Mn electrode material was found to have higher catalytic activity than GAC-Co by LC-MS, indicating that the synergistic effect of the bimetallic can better enhance the electrocatalytic activity.
In recent years, there has been an increasing interest in advanced oxidation processes based on persulfate (PS-AOPs), which has a stronger redox potential (2.5–3.1 V vs. 1.8–2.7 V), a longer half-life and a wider pH range than ·OH (SO4·− the half-life of 30–40 μs and ·OH half-life of fewer than 1 μs) and is easier to store and transport [41,42]. PS-AOPs are now successfully used in the textile industry as well as in oil extraction. Due to the limited degradation capacity of persulfate, it is not possible to achieve rapid removal of pollutants, so effective activation of persulfate is required to enhance its effectiveness in the oxidative degradation of organic pollutants. Common activation methods include thermal activation, UV activation, alkali activation and metal/transition metal activation [43]. The most basic of the many activation methods is to increase the amount of SO4·− produced by increasing the temperature of the system so that the persulfate absorbs thermal energy to promote the cleavage of the O-O bond. Liu et al. [44] demonstrated that thermally-activated persulfate can effectively degrade sulfapyridine in water, and the mechanism of thermal activation is shown in Equations (1) and (2). The consumption rate of persulfate increases with increasing temperature and reaches its optimum degradation at 40 °C. The reason for this is that the increase in temperature accelerates the consumption of persulfate, leading to an increase in the concentration of free radicals in solution. However, thermal activation also suffers from higher applied energy for the experiment due to the controlled temperature, leading to its increased cost.
S2O82−→2·SO4−
HSO5−→·SO4− + ·OH
Catalyst activation of persulphates is simpler than light and heat activation of persulphates. The heterogeneous catalyst can be activated at room temperature and pressure has low pH requirements and does not require an external energy input, which has been considered in recent years as an environmentally friendly way of activating persulphates. Commonly used heterogeneous catalysts include zero-valent metals, carbon materials, metals and metal oxides [42,45]. Chen et al. [46] prepared nitrogen-doped porous carbon-encapsulated iron nanoparticles (CN-Fe) for activation of peroxymonosulfate degradation of STZ using polyaniline and αFe2O3 as precursors, achieving 96% removal in 40 min with 57% mineralization. Ji et al. [47] effectively degraded SMX using persulfate activated by ferrous ions (Fe2+), and the degradation efficiency was enhanced when the chelating agent’s citrate (CA) and ethylene diamine tetraacetic acid (EDTA) was added. However, metal and metal oxide activation techniques also suffer from high costs and secondary contamination caused by the unstable leaching of metal ions. Carbon materials are widely used in the activation of persulfates for the removal of organic pollutants due to the absence of metal ion leaching, environmental friendliness and more stable catalytic capacity [48]. Nanomaterials, such as diamond, graphitic carbon, carbon nanotubes and porous carbon, could all activate PMS to degrade organic matter. Shang et al. [49] prepared nitrogen-doped carbon nanotube materials by primary pyrolysis for the activated peroxynitrite degradation of SMX, and clear structures of carbon nanotubes (CNTs) were observed by SEM and TEM with good removal of SMX. In addition to carbon materials, MOFs are also porous materials that have emerged in recent years for the activation of persulfates. Among the commonly used precursor MOFs are ZIF-8, ZIF-67, MIL-100 (Fe) and UiO-66 [50,51,52]. Pu et al. [53] synthesized three new iron-based MOFs persulfate activators for the degradation of SMX. Experimental results showed that all iron-based MOFs catalysts could effectively activate persulfate and degraded more than 97% of SMX within 180 min. Wang et al. [54] systematically investigated the catalytic performance of CoSx@SiO2 nanocages as multiphase catalysts for the activation of peroxynitrite for SMX degradation by hydrothermal synthesis of amorphous CoSx@SiO2 nanocages via sulfated ZIF-67@SiO2, and 100% of SMX was removed within 6 min. The catalyst also showed good stability and reusability, achieving 100% removal of SMX after five consecutive cycles. In addition, AOPs have the advantages of simple operation, fast treatment speed and strong adaptability to water quality, and has been widely used in industry. While AOPs demonstrate remarkable advantages in SAs remediation, including broad-spectrum applicability for recalcitrant compounds and significantly smaller spatial requirements compared to biological systems, their practical implementation faces notable challenges. Substantial energy consumption and chemical inputs result in operational costs 3–5 times higher than conventional biological treatments, particularly for low-concentration SA wastewater (<1 mg/L) [55]. Furthermore, the non-selective nature of radical oxidation (·OH/SO₄·−) may generate transformation products that retain antibiotic activity or exhibit enhanced toxicity, with some derivatives showing 2–3 times higher ecotoxicity than the parent compounds. Technical constraints, including pH sensitivity, interference from aqueous matrix components, and catalyst stability issues, further limit large-scale deployment [56]. Nevertheless, with continuous breakthroughs in catalyst design and process optimization, the synergistic integration of AOPs with complementary technologies has demonstrated significant advantages, offering sustainable solutions for thorough elimination of SAs in complex environmental matrices.

5. Conclusions and Prospects

(I) Research on SAs in the environment internationally and domestically can be categorized into three stages: initial exploration, slow development and in-depth research. China and the United States are the two most productive countries on SAs with the strongest collaborative ties. Science of the Total Environment is the journal with the highest publication count.
(II) The research trends have evolved as a progression from initial efficient detection of SAs in the environment and analysis of their sources, to studying the effectiveness of biotechnological approaches for degradation of SAs, to the development of different AOPs for efficient removal of SAs from wastewater.
(III) The future should prioritize addressing the problem of antibiotic-resistant bacteria and antibiotic-resistant genes associated with SAs in the environment, as well as the development of more effective integrated technologies to achieve efficient removal of SAs and reduce the concentration of SAs and their hazards in the environment.

Author Contributions

Data curation, X.L.; Formal analysis, J.S.; Methodology, J.W.; Resources, X.L.; Supervision, J.S.; Writing—original draft, J.W.; Writing—review and editing, F.Q. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding authors.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Zainab, S.M.; Junaid, M.; Xu, N.; Malik, R.N. Antibiotics and Antibiotic Resistant Genes (ARGs) in Groundwater: A Global Review on Dissemination, Sources, Interactions, Environmental and Human Health Risks. Water Res. 2020, 187, 116455. [Google Scholar] [CrossRef] [PubMed]
  2. Xu, L.; Zhang, H.; Xiong, P.; Zhu, Q.; Liao, C.; Jiang, G. Occurrence, Fate, and Risk Assessment of Typical Tetracycline Antibiotics in the Aquatic Environment: A Review. Sci. Total Environ. 2021, 753, 141975. [Google Scholar] [CrossRef] [PubMed]
  3. Duan, W.; Cui, H.; Jia, X.; Huang, X. Occurrence and Ecotoxicity of Sulfonamides in the Aquatic Environment: A Review. Sci. Total Environ. 2022, 820, 153178. [Google Scholar] [CrossRef]
  4. Yin, R.; Guo, W.; Wang, H.; Du, J.; Zhou, X.; Wu, Q.; Zheng, H.; Chang, J.; Ren, N. Selective Degradation of Sulfonamide Antibiotics by Peroxymonosulfate Alone: Direct Oxidation and Nonradical Mechanisms. Chem. Eng. J. 2018, 334, 2539–2546. [Google Scholar] [CrossRef]
  5. Zhou, L.; Yang, X.; Ji, Y.; Wei, J. Sulfate Radical-Based Oxidation of the Antibiotics Sulfamethoxazole, Sulfisoxazole, Sulfathiazole, and Sulfamethizole: The Role of Five-Membered Heterocyclic Rings. Sci. Total Environ. 2019, 692, 201–208. [Google Scholar] [CrossRef]
  6. Ni, Z.; Zhou, L.; Lin, Z.; Kuang, B.; Zhu, G.; Jia, J.; Wang, T. Iron-Modified Biochar Boosts Anaerobic Digestion of Sulfamethoxazole Pharmaceutical Wastewater: Performance and Microbial Mechanism. J. Hazard. Mater. 2023, 452, 131314. [Google Scholar] [CrossRef]
  7. Feng, G.; Huang, H.; Chen, Y. Effects of Emerging Pollutants on the Occurrence and Transfer of Antibiotic Resistance Genes: A Review. J. Hazard. Mater. 2021, 420, 126602. [Google Scholar] [CrossRef]
  8. Wang, J.; Chu, L.; Wojnárovits, L.; Takács, E. Occurrence and Fate of Antibiotics, Antibiotic Resistant Genes (ARGs) and Antibiotic Resistant Bacteria (ARB) in Municipal Wastewater Treatment Plant: An Overview. Sci. Total Environ. 2020, 744, 140997. [Google Scholar] [CrossRef]
  9. Chen, C. CiteSpace II: Detecting and Visualizing Emerging Trends and Transient Patterns in Scientific Literature. J. Am. Soc. Inf. Sci. Technol. 2006, 57, 359–377. [Google Scholar] [CrossRef]
  10. Van Eck, N.J.; Waltman, L. Software Survey: VOSviewer, a Computer Program for Bibliometric Mapping. Scientometrics 2010, 84, 523–538. [Google Scholar] [CrossRef]
  11. Ma, W.; Yuan, R. A Visualization Analysis of Biblioshiny Based Measurement of Digital Reading Studies. Libr. Inf. Stud. 2021, 14, 100–108. [Google Scholar]
  12. Shi, X.; Li, L.; Zhang, T. Water Ten solid lines—Interpretation of the Action Plan for Water Pollution Control. Environ. Prot. Sci. 2015, 41, 1–3. [Google Scholar] [CrossRef]
  13. Zhao, R.; Xu, L. Research on the evolution of bibliometrics and the Knowledge graph of the research Frontier. J. Libr. Sci. China 2010, 36, 60–68. [Google Scholar] [CrossRef]
  14. Chen, X.; Cheng, X.; Meng, H.; Selvaraj, K.K.; Li, H.; He, H.; Du, W.; Yang, S.; Li, S.; Zhang, L. Past, Present, and Future Perspectives on the Assessment of Bioavailability/Bioaccessibility of Polycyclic Aromatic Hydrocarbons: A 20-Year Systemic Review Based on Scientific Econometrics. Sci. Total Environ. 2021, 774, 145585. [Google Scholar] [CrossRef]
  15. Zhu, T.; Su, Z.; Lai, W.; Zhang, Y.; Liu, Y. Insights into the Fate and Removal of Antibiotics and Antibiotic Resistance Genes Using Biological Wastewater Treatment Technology. Sci. Total Environ. 2021, 776, 145906. [Google Scholar] [CrossRef]
  16. Hu, J.; Li, X.; Liu, F.; Fu, W.; Lin, L.; Li, B. Comparison of Chemical and Biological Degradation of Sulfonamides: Solving the Mystery of Sulfonamide Transformation. J. Hazard. Mater. 2022, 424, 127661. [Google Scholar] [CrossRef] [PubMed]
  17. Meng, H.; Huang, J.; Cheng, X.; Pan, G.; Fan, M.; Cai, X. Theoretical study on bond dissociation energy of polyethylene terephthalate dimer modulates. J. Mol. Sci. 2021, 37, 261–267. [Google Scholar] [CrossRef]
  18. Wang, Z.; Chen, J.; Chen, J.; Xu, H. Toxicity and ecological risk assessment of complex residues of antibiotics in surface water to aquatic organisms. Asian J. Ecotoxicol. 2018, 13, 149–160. [Google Scholar]
  19. Mohapatra, S.; Huang, C.-H.; Mukherji, S.; Padhye, L. Corrigendum to “Occurrence and Fate of Pharmaceuticals in WWTPs in India and Comparison with a Similar Study in the United States” [Chemosphere 159 526–535]. Chemosphere 2023, 322, 138161. [Google Scholar] [CrossRef]
  20. Zhou, L.-J.; Ying, G.-G.; Liu, S.; Zhao, J.-L.; Chen, F.; Zhang, R.-Q.; Peng, F.-Q.; Zhang, Q.-Q. Simultaneous Determination of Human and Veterinary Antibiotics in Various Environmental Matrices by Rapid Resolution Liquid Chromatography–Electrospray Ionization Tandem Mass Spectrometry. J. Chromatogr. A 2012, 1244, 123–138. [Google Scholar] [CrossRef]
  21. García-Galán, M.J.; González Blanco, S.; López Roldán, R.; Díaz-Cruz, S.; Barceló, D. Ecotoxicity Evaluation and Removal of Sulfonamides and Their Acetylated Metabolites during Conventional Wastewater Treatment. Sci. Total Environ. 2012, 437, 403–412. [Google Scholar] [CrossRef] [PubMed]
  22. Biošić, M.; Mitrevski, M.; Babić, S. Environmental Behavior of Sulfadiazine, Sulfamethazine, and Their Metabolites. Environ. Sci. Pollut. Res. 2017, 24, 9802–9812. [Google Scholar] [CrossRef] [PubMed]
  23. Wang, R.; Ji, M.; Zhai, H.; Guo, Y.; Liu, Y. Occurrence of Antibiotics and Antibiotic Resistance Genes in WWTP Effluent-Receiving Water Bodies and Reclaimed Wastewater Treatment Plants. Sci. Total Environ. 2021, 796, 148919. [Google Scholar] [CrossRef]
  24. Tang, N.; Zhang, S.; Chen, M.; Song, N.; Xu, H.; Zhang, Q. Pollution levels and risk assessment of 12 sulfonamides in surface water of Nanjing Section of Yangtze River. Environ. Chem. 2018, 37, 505–512. [Google Scholar]
  25. Hijosa-Valsero, M.; Fink, G.; Schlüsener, M.P.; Sidrach-Cardona, R.; Martín-Villacorta, J.; Ternes, T.; Bécares, E. Removal of Antibiotics from Urban Wastewater by Constructed Wetland Optimization. Chemosphere 2011, 83, 713–719. [Google Scholar] [CrossRef]
  26. Sim, W.-J.; Lee, J.-W.; Lee, E.-S.; Shin, S.-K.; Hwang, S.-R.; Oh, J.-E. Occurrence and Distribution of Pharmaceuticals in Wastewater from Households, Livestock Farms, Hospitals and Pharmaceutical Manufactures. Chemosphere 2011, 82, 179–186. [Google Scholar] [CrossRef] [PubMed]
  27. Gao, L.; Shi, Y.; Li, W.; Niu, H.; Liu, J.; Cai, Y. Occurrence of antibiotics in eight sewage treatment plants in Beijing, China. Chemosphere 2012, 86, 665–671. [Google Scholar] [CrossRef]
  28. Kasprzyk-Hordern, B.; Dinsdale, R.M.; Guwy, A.J. The Removal of Pharmaceuticals, Personal Care Products, Endocrine Disruptors and Illicit Drugs during Wastewater Treatment and Its Impact on the Quality of Receiving Waters. Water Res. 2009, 43, 363–380. [Google Scholar] [CrossRef]
  29. Zhang, X.; Zhao, H.; Du, J.; Qu, Y.; Shen, C.; Tan, F.; Chen, J.; Quan, X. Occurrence, Removal, and Risk Assessment of Antibiotics in 12 Wastewater Treatment Plants from Dalian, China. Environ. Sci. Pollut. Res. 2017, 24, 16478–16487. [Google Scholar] [CrossRef]
  30. Li, M.; Wang, C.; Yau, M.; Bolton, J.R.; Qiang, Z. Sulfamethazine Degradation in Water by the VUV/UV Process: Kinetics, Mechanism and Antibacterial Activity Determination Based on a Mini-Fluidic VUV/UV Photoreaction System. Water Res. 2017, 108, 348–355. [Google Scholar] [CrossRef]
  31. Yu, F.; Li, Y.; Han, S.; Ma, J. Adsorptive Removal of Antibiotics from Aqueous Solution Using Carbon Materials. Chemosphere 2016, 153, 365–385. [Google Scholar] [CrossRef]
  32. Zeng, X.; Sun, X.; Meng, Y.; Yu, N.; Liu, J. Photodegradation of Sulfamethoxypyridazine in UV/Co(II)/Peroxymonosulfate System: Kinetics, Influencing Factors, Degradation Pathways, and Toxicity Assessment. Water Air Soil. Pollut. 2021, 232, 410. [Google Scholar] [CrossRef] [PubMed]
  33. Chávez, A.M.; Beltrán, F.J.; López, J.; Javier Rivas, F.; Álvarez, P.M. On the Importance of Reactions in the Proximity of the Gas–Water Interface: Application to Direct Ozone Reactions of Antibiotics in Water. Chem. Eng. J. 2023, 458, 141408. [Google Scholar] [CrossRef]
  34. Wang, L.; Xiao, K.; Zhao, H. The Debatable Role of Singlet Oxygen in Persulfate-Based Advanced Oxidation Processes. Water Res. 2023, 235, 119925. [Google Scholar] [CrossRef] [PubMed]
  35. Gao, Y.; Wang, Q.; Ji, G.; Li, A. Degradation of Antibiotic Pollutants by Persulfate Activated with Various Carbon Materials. Chem. Eng. J. 2022, 429, 132387. [Google Scholar] [CrossRef]
  36. Xiao, G.; Chen, J.; Show, P.L.; Yang, Q.; Ke, J.; Zhao, Q.; Guo, R.; Liu, Y. Evaluating the Application of Antibiotic Treatment Using Algae-Algae/Activated Sludge System. Chemosphere 2021, 282, 130966. [Google Scholar] [CrossRef]
  37. Yin, R.; Guo, W.; Du, J.; Zhou, X.; Zheng, H.; Wu, Q.; Chang, J.; Ren, N. Heteroatoms Doped Graphene for Catalytic Ozonation of Sulfamethoxazole by Metal-Free Catalysis: Performances and Mechanisms. Chem. Eng. J. 2017, 317, 632–639. [Google Scholar] [CrossRef]
  38. Tan, X.; Ding, W.; Jiang, Z.; Sun, L.; Huang, Y. Reinventing MoS2 Co-Catalytic Fenton Reaction: Oxygen-Incorporation Mediating Surface Superoxide Radical Generation. Nano Res. 2022, 15, 1973–1982. [Google Scholar] [CrossRef]
  39. Wen, D.; Wu, Z.; Tang, Y.; Li, M.; Qiang, Z. Accelerated Degradation of Sulfamethazine in Water by VUV/UV Photo-Fenton Process: Impact of Sulfamethazine Concentration on Reaction Mechanism. J. Hazard. Mater. 2018, 344, 1181–1187. [Google Scholar] [CrossRef]
  40. Rajasekhar, B.; Venkateshwaran, U.; Durairaj, N.; Divyapriya, G.; Nambi, I.M.; Joseph, A. Comprehensive Treatment of Urban Wastewaters Using Electrochemical Advanced Oxidation Process. J. Environ. Manag. 2020, 266, 110469. [Google Scholar] [CrossRef]
  41. Yang, Q.; Ma, Y.; Chen, F.; Yao, F.; Sun, J.; Wang, S.; Yi, K.; Hou, L.; Li, X.; Wang, D. Recent Advances in Photo-Activated Sulfate Radical-Advanced Oxidation Process (SR-AOP) for Refractory Organic Pollutants Removal in Water. Chem. Eng. J. 2019, 378, 122149. [Google Scholar] [CrossRef]
  42. Wang, J.; Wang, S. Activation of Persulfate (PS) and Peroxymonosulfate (PMS) and Application for the Degradation of Emerging Contaminants. Chem. Eng. J. 2018, 334, 1502–1517. [Google Scholar] [CrossRef]
  43. Fu, C.; Yi, X.; Liu, Y.; Zhou, H. Cu2+ Activated Persulfate for Sulfamethazine Degradation. Chemosphere 2020, 257, 127294. [Google Scholar] [CrossRef] [PubMed]
  44. Liu, L.; Lin, S.; Zhang, W.; Farooq, U.; Shen, G.; Hu, S. Kinetic and Mechanistic Investigations of the Degradation of Sulfachloropyridazine in Heat-Activated Persulfate Oxidation Process. Chem. Eng. J. 2018, 346, 515–524. [Google Scholar] [CrossRef]
  45. Xiao, R.; Luo, Z.; Wei, Z.; Luo, S.; Spinney, R.; Yang, W.; Dionysiou, D.D. Activation of Peroxymonosulfate/Persulfate by Nanomaterials for Sulfate Radical-Based Advanced Oxidation Technologies. Curr. Opin. Chem. Eng. 2018, 19, 51–58. [Google Scholar] [CrossRef]
  46. Chen, L.; Huang, Y.; Zhou, M.; Xing, K.; Lv, W.; Wang, W.; Chen, H.; Yao, Y. Nitrogen-Doped Porous Carbon Encapsulating Iron Nanoparticles for Enhanced Sulfathiazole Removal via Peroxymonosulfate Activation. Chemosphere 2020, 250, 126300. [Google Scholar] [CrossRef]
  47. Ji, Y.; Ferronato, C.; Salvador, A.; Yang, X.; Chovelon, J.-M. Degradation of Ciprofloxacin and Sulfamethoxazole by Ferrous-Activated Persulfate: Implications for Remediation of Groundwater Contaminated by Antibiotics. Sci. Total Environ. 2014, 472, 800–808. [Google Scholar] [CrossRef]
  48. Saputra, E.; Muhammad, S.; Sun, H.; Wang, S. Activated Carbons as Green and Effective Catalysts for Generation of Reactive Radicals in Degradation of Aqueous Phenol. RSC Adv. 2013, 3, 21905–21910. [Google Scholar] [CrossRef]
  49. Shang, Y.; Chen, C.; Zhang, P.; Yue, Q.; Li, Y.; Gao, B.; Xu, X. Removal of Sulfamethoxazole from Water via Activation of Persulfate by Fe3C@NCNTs Including Mechanism of Radical and Nonradical Process. Chem. Eng. J. 2019, 375, 122004. [Google Scholar] [CrossRef]
  50. Heydari Moghaddam, M.; Nabizadeh, R.; Dehghani, M.H.; Akbarpour, B.; Azari, A.; Yousefi, M. Performance Investigation of Zeolitic Imidazolate Framework—8 (ZIF-8) in the Removal of Trichloroethylene from Aqueous Solutions. Microchem. J. 2019, 150, 104185. [Google Scholar] [CrossRef]
  51. Peng, L.; Gong, X.; Wang, X.; Yang, Z.; Liu, Y. In Situ Growth of ZIF-67 on a Nickel Foam as a Three-Dimensional Heterogeneous Catalyst for Peroxymonosulfate Activation. RSC Adv. 2018, 8, 26377–26382. [Google Scholar] [CrossRef] [PubMed]
  52. Lin, K.-Y.A.; Chang, H.-A. Zeolitic Imidazole Framework-67 (ZIF-67) as a Heterogeneous Catalyst to Activate Peroxymonosulfate for Degradation of Rhodamine B in Water. J. Taiwan Inst. Chem. Eng. 2015, 53, 40–45. [Google Scholar] [CrossRef]
  53. Pu, M.; Niu, J.; Brusseau, M.L.; Sun, Y.; Zhou, C.; Deng, S.; Wan, J. Ferrous Metal-Organic Frameworks with Strong Electron-Donating Properties for Persulfate Activation to Effectively Degrade Aqueous Sulfamethoxazole. Chem. Eng. J. 2020, 394, 125044. [Google Scholar] [CrossRef] [PubMed]
  54. Wang, F.; Fu, H.; Wang, F.-X.; Zhang, X.-W.; Wang, P.; Zhao, C.; Wang, C.-C. Enhanced Catalytic Sulfamethoxazole Degradation via Peroxymonosulfate Activation over Amorphous CoSx@SiO2 Nanocages Derived from ZIF-67. J. Hazard. Mater. 2022, 423, 126998. [Google Scholar] [CrossRef]
  55. Li, J.; Peng, X.; Zeng, P.; Shen, L.; Li, M.; Guo, Y. Removal of Sulfonamides by Persulfate-Based Advanced Oxidation: A Mini Review. Chemosphere 2025, 370, 143874. [Google Scholar] [CrossRef]
  56. Martini, J.; Orge, C.A.; Faria, J.L.; Pereira, M.F.R.; Soares, O.S.G.P. Sulfamethoxazole Degradation by Combination of Advanced Oxidation Processes. J. Environ. Chem. Eng. 2018, 6, 4054–4060. [Google Scholar] [CrossRef]
Water 17 01792 g001
Figure 1. The trend of publications in the research field of SAs treatment.
Figure 1. The trend of publications in the research field of SAs treatment.
Water 17 01792 g001
Water 17 01792 g002
Figure 2. Exchanges and cooperation among countries in the treatment of SAs.
Figure 2. Exchanges and cooperation among countries in the treatment of SAs.
Water 17 01792 g002
Water 17 01792 g003
Figure 3. Journal-Country-Keyword Sankey map.
Figure 3. Journal-Country-Keyword Sankey map.
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Figure 4. Keyword co-occurrence network diagram.
Figure 4. Keyword co-occurrence network diagram.
Water 17 01792 g004
Water 17 01792 g005
Figure 5. Keyword cluster analysis diagram.
Figure 5. Keyword cluster analysis diagram.
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Figure 6. Keywords hot spot analysis diagram (a); Keywords change over time heat map (b).
Figure 6. Keywords hot spot analysis diagram (a); Keywords change over time heat map (b).
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Water 17 01792 g007
Figure 7. Pie distribution diagram of the number of published documents by different treatment technologies (a); Histogram of different treatment techniques with different years (b).
Figure 7. Pie distribution diagram of the number of published documents by different treatment technologies (a); Histogram of different treatment techniques with different years (b).
Water 17 01792 g007
Table 1. Top ten countries in the field of SAs treatment.
Table 1. Top ten countries in the field of SAs treatment.
RankingCountry/RegionNumberTotal Citation FrequencyCitations per ArticleH-Index
1China226677,36339.03133
2USA59241,94472.94107
3Spain41122,79857.7183
4Germany28415,38255.8262
5Canada180888450.652
6France158640041.5444
7Australia150764351.7345
8Republic of Korea145815057.247
9Brazil137282621.5531
10Portugal110426739.7134
Table 2. Top eight institutions in the field of SAs treatment.
Table 2. Top eight institutions in the field of SAs treatment.
RankingInstitutionNumberTotal Citation FrequencyCitations per ArticleH-Index
1Chinese Academy of Sciences34818,61455.6377
2Tsinghua University178660539.1645
3Harbin Institute of Technology129474637.7639
4University of Chinese Academy of Sciences120460639.1339
5Spanish Higher Scientific Council109845779.3950
6French National Centre for Scientific Research95398642.8335
7Tongji University92294632.7533
8Research Center for ECO Environmental Science90503556.8741
Table 3. The physical and chemical properties of the main sulfonamide antibiotics.
Table 3. The physical and chemical properties of the main sulfonamide antibiotics.
CompoundMolecular FormulaChemical ConstructionMolecular Mass (g/mol)Acidity Coefficient pKaLD50
mg/kg		Bio EnrichmentCAS
SulfamethoxazoleC10H11N3O3SWater 17 01792 i001253.28pKa1 = 2.10
pKa2 = 5.30		1.471.23723-46-6
SulfamethazineC12H14N4O2SWater 17 01792 i002278.33pKa1 = 2.65
pKa2 = 7.40		1.590.4157-68-1
SulfadiazineC10H10N4O2SWater 17 01792 i003250.28pKa1 = 2.72
pKa2 = 8.56		1.470.2468-35-9
SulfamerazineC11H12N4O2SWater 17 01792 i004264.30pKa1 = 2.10
pKa2 = 6.28		1.540.30127-79-7
SulfathiazoleC9H9N3O2S2Water 17 01792 i005255.32pKa1 = 2.08
pKa2 = 7.07		1.990.3572-14-0
SulfamethizoleC9H10N4O2S2Water 17 01792 i006270.33pKa1 = 5.45
pKa2 = 7.40		2.100.32144-82-1
SulfachloropyridazineC10H9CIN4O2SWater 17 01792 i007284.72-1.810.6980-32-0
SulfisoxazoleC11H13N3O3SWater 17 01792 i008267.3-1.580.70127-69-5
SulfamethoxypyridazineC11H12N4O3SWater 17 01792 i009280.30pKa1 = 2.18
pKa2 = 7.19		1.780.4280-35-3
SulfamonomethoxineC11H12N4O3SWater 17 01792 i010280.30pKa1 = 2.00
pKa2 = 6.01		1.480.301220-83-3
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Wang, J.; Liu, X.; Qian, F.; Su, J. Analysis of Hotspots in the Field of Sulfonamides Treatment: A Bibliometric Review. Water 2025, 17, 1792. https://doi.org/10.3390/w17121792

AMA Style

Wang J, Liu X, Qian F, Su J. Analysis of Hotspots in the Field of Sulfonamides Treatment: A Bibliometric Review. Water. 2025; 17(12):1792. https://doi.org/10.3390/w17121792

Chicago/Turabian Style

Wang, Jian, Xinyao Liu, Feng Qian, and Jie Su. 2025. "Analysis of Hotspots in the Field of Sulfonamides Treatment: A Bibliometric Review" Water 17, no. 12: 1792. https://doi.org/10.3390/w17121792

APA Style

Wang, J., Liu, X., Qian, F., & Su, J. (2025). Analysis of Hotspots in the Field of Sulfonamides Treatment: A Bibliometric Review. Water, 17(12), 1792. https://doi.org/10.3390/w17121792

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