Search Results (42)

The study aimed to evaluate the effect of chlorhexidine (CHX), chlorin p6-mediated photodynamic therapy (PDT), magnesium oxide nanoparticles (MgONPs), and Clp6-functionalized MgONPs on smear layer removal and shear bond strength of a two-step etch-and-rinse adhesive to caries-affected dentin. Seventy-five human permanent molars with occlusal carious lesions and ICDAS scores of four and five were included. Twenty-five samples were used to prepare dentin discs 2 mm in thickness. The remaining samples, along with 25 discs, were arbitrarily allocated into five disinfectant groups, with n = 15 per group (10 teeth and 5 discs). Group I: Control, Group II: 2% CHX, Group III: Clp6-mediated PDT, Group IV: MgONPs, and Group V: Clp6-functionalized MgONPs. SL removal assessment, nanoparticle characterization, and EDX were performed using SEM. Fifty CAD were etched, followed by fifth-generation adhesive application and composite build-up. SBS and failure modes were evaluated with a universal testing machine and stereomicroscope, respectively. Group 4 (MgONPs) specimens displayed the maximum cleaning of SL (1.11 ± 0.13) and the highest SBS (10.32 ± 0.18 MPa). However, minimum SL removal (2.87 ± 0.94) and bond strength (7.42 ± 0.25 MPa) were exhibited by Group 1 (No disinfectant) samples. MgONPs possess the potential to be used as a cavity disinfectant, as they efficiently remove SL from CAD and augment the bond integrity outcomes. Full article

In this work, iron–phosphorus-based composite biochar (FPBC) was prepared by modification with the leachate of spent LiFePO₄ batteries. The effects of solution pH, dosage, adsorption time, initial concentration, and temperature on the adsorption performance of FPBC were investigated by batch adsorption experiments with Pb(II) and Sb(III) as the target pollutants, and the adsorption mechanism was explored using SEM, BET, XPS, FTIR and XRD characterization. The results indicated that as the initial pH of the solution increased, the removal efficiency of FPBC for Pb(II) gradually increased, while the removal efficiency for Sb(III) remained largely unchanged. The removal of Pb(II) and Sb(III) by FPBC fitted the pseudo-second-order kinetic model and the three-step intraparticle diffusion model, indicating that their removal was primarily controlled by chemical adsorption. Isothermal adsorption studies revealed that FPBC adsorption of Pb(II) better fitted the Langmuir and D-R models, suggesting a monolayer-dominated adsorption process. In contrast, adsorption of Sb(III) fitted the Langmuir, Freundlich, and Temkin models, suggesting a combination of monolayer and multilayer adsorption characteristics. The maximum adsorption capacities of FPBC for Pb(II) and Sb(III) were 312.54 mg·g⁻¹ and 219.20 mg·g⁻¹ at 30 °C, which were approximately 12.85 and 3.37 times those of commercial corn stalk biochar (BC). Thermodynamic analysis confirmed that the removal of Pb(II) and Sb(III) by FPBC was a spontaneous and endothermic process. In addition, FPBC demonstrated strong selective adsorption of Pb(II) in the binary co-adsorption system of Pb(II) and Sb(III). Mechanism studies indicated that Pb(II) removal primarily occurred through co-precipitation, complexation, ion exchange, and electrostatic adsorption, while Sb(III) was mainly adsorbed by FPBC via redox reactions and complexation. Therefore, this work not only provides a low-cost, high-performance adsorbent for the remediation of water contaminated with Pb(II) and Sb(III), but also opens up new avenues for the resource recovery of the leachate of spent LiFePO₄ batteries. Full article

Antimony (Sb) contamination in water poses significant environmental and health risks due to its high toxicity, persistence and complex redox behavior. Magnetic spinel ferrites (MFe₂O₄) have shown promise for Sb removal; however, the intrinsic influence of divalent metal species (M²⁺) in regulating Sb(III)/Sb(V) adsorption performance and interfacial mechanisms remains poorly understood. In this study, MnFe₂O₄, ZnFe₂O₄ and NiFe₂O₄ nanoparticles were synthesized and systematically evaluated to elucidate how M²⁺ governs Sb immobilization behavior. Batch adsorption experiments revealed pronounced M–dependent selectivity. MnFe₂O₄ exhibited the highest Sb(III) adsorption capacity (229.89 mg·g⁻¹), whereas NiFe₂O₄ showed superior affinity toward Sb(V) (up to 257.07 mg·g⁻¹). Adsorption kinetics for both Sb species followed pseudo-second-order models, indicating chemically controlled processes. Isotherm analyses indicated predominantly monolayer complexation for Sb(III), while Sb(V) adsorption displayed mixed adsorption characteristics, reflecting surface heterogeneity. Mechanistic investigations based on FTIR and XPS analyses suggest that Sb(III) immobilization is dominated by inner-sphere complexation with surface Fe–O/Fe–OH groups, whereas Sb(V) adsorption involves synergistic coordination with both Fe–O and M–O (Mn–O/Ni–O) functional groups. XPS analysis of Sb-loaded ZnFe₂O₄ revealed the coexistence of Sb(III) and Sb(V) species after Sb(III) adsorption, indicating surface-confined partial oxidation; the extent of solution-phase conversion was not independently quantified. Therefore, the redox process is interpreted as an interfacial phenomenon rather than bulk oxidation in solution. These results clarify that M²⁺ species influence Sb removal behavior by modulating the reactivity of surface functional groups and interfacial redox characteristics, rather than merely altering adsorption capacity. This work provides spectroscopic insight into M-dependent structure–activity relationships in spinel ferrites and offers a theoretical basis for the rational design of magnetic adsorbents for selective and efficient Sb remediation. Full article

Pollution by Sb, which is widely used in industry and agriculture, poses serious threats to ecosystems. This study demonstrates, for the first time, that sodium alginate (ALG) modified by polyethyleneimine (PEI) has good adsorption capacity for Sb(III) (the theoretical maximum adsorption capacity was 978 mg/g, and the actual maximum adsorption capacity was 743 mg/g) and can retain 90–98% of the initial removal rate after eight cycles of reuse. The inorganic ions and humic acid in Sb(III)-containing wastewater do not affect the adsorption capacity of PEI/ALG within a certain pH range. However, it was also found that the adsorption was interfered with by Sb(III) precipitation, phosphate ions, and some coexisting cations/metalloids such as Ni, Cd, Pb, and As under higher pH conditions, and the recovery rate of antimony in the desorption process needs to be further improved. Density functional theory calculations reveal that the -OH, -COOH, -NH₂, -NH-, and -N= in PEI/ALG show strong binding with Sb (−56.85, −28.39, −17.98, −25.76, and −17.98 kcal/mol, respectively), enabling these functional groups to easily form stable composite structures with Sb(III). This characteristic enables PEI/ALG to selectively adsorb Sb(III) under certain conditions. Combining these findings with the characterization analysis results indicates that the mechanism of PEI/ALG adsorption of Sb(III) is mainly the formation of H bonds and coordination between -OH, -COOH, and Sb(III). The selective adsorption mechanism of PEI/ALG for Sb(III) has not been investigated previously, and our research results indicate the high potential of this approach. Full article

Antimony (Sb), as a toxic heavy metal, has drawn worldwide attention, and its efficient removal from water has become increasingly urgent. In this study, an iron-modified alkaline lignin chitosan (Fe-ALCS) gel bead is prepared by the freeze-drying method to remove Sb(III) from the aqueous solution. The static adsorption experiment discusses the various environmental influences on the adsorption performance of Fe-ALCS for Sb(III) removal. The adsorption mechanism is explored by combining adsorption kinetics, isothermal adsorption, and characterization methods (such as FTIR, XRD, XPS, etc). The results show that the equilibrium adsorption capacity of Sb(III) decreases with the increase in pH and mass–volume ratio. With the increase in the initial Sb(III) concentration, Q_e showed a rapid increasing trend in the range of 50–100 mg/L and continued to rise with the extension of contact time (t), reaching the maximum value at 3540 min. Under the optimal conditions of pH = 3, m/v = 1.0 g/L, and C₀ = 20 mg/L, the removal efficiency (R_e) value is 95.07%, which is still approximately 86.8% after five adsorption–desorption cycles. The maximum adsorption capacity is 266.58 mg/g fitted by the Langmuir model. The adsorption mechanism is mainly related to the iron-based active site of Fe–O(OH), where the O–H on its surface undergoes ligand exchange with Sb(OH)₃ to form a stable Fe–O–Sb coordination structure. Additionally, C–OH, C–O, and other functional groups in ALCS also contribute to Sb adsorption. Fe-ALCS is an environmentally friendly, renewable, and convenient biomass adsorbent with good potential for wastewater treatment. Full article

Background: Proximal gastrectomy (PG) with double tract reconstruction (DTR) offers organ preservation for early gastric cancers, leading to reduced vitamin B12 deficiency, less weight loss, and improved quality of life. The JCOG1401 study confirmed excellent long-term outcomes for PG in stage I gastric cancer. However, in locally advanced proximal gastric cancer (LAPGC), preserving the gastric body and lymph node station 4d may compromise margin clearance and adequate lymphadenectomy. Methods: We propose a modified PG that removes the distal esophagus, gastroesophageal junction (GEJ), cardia, fundus, and gastric body, preserving only the antrum and performing DTR. Lymphadenectomy is also adapted, removing stations 1, 2, 3a, 4sa, 4sb, 4d, 7, 8, 9, 10 (spleen preserving), 11, and lower mediastinal nodes (stations 19, 20, and 110), while preserving stations 3b, 5, and 6. Indications for this procedure include GEJ (Siewert type II and III) and proximal gastric cancers with ≤2 cm distal esophageal involvement and ≤5 cm gastric involvement. Results: In our initial experience with 14 patients, we achieved R0 resection in all patients, adequate lymph node harvest (median 24 nodes, IQR 18–38), and no locoregional recurrences at a median follow-up of 18 months. We also found favorable postoperative weight loss, reflux, and anemia in the PG cohort. Conclusion: While larger studies and long-term data are still needed, our early results suggest that modified PG—despite sparing only the antrum—retains the key benefits of PG over total gastrectomy, including better weight maintenance and improved hemoglobin levels, while maintaining oncologic outcomes for LAPGC. Full article

The development of the non-ferrous metal industry is generating increasingly large quantities of wastewater containing heavy metals (e.g., Sb). The precipitation of heavy metals by microorganisms involves complex mechanisms that require further investigation to optimize bioremediation technologies. In this study, we employed a sulfate-reducing bacteria (SRB) strain Desulfovibrio desulfuricans CSU_dl to treat the antimony (Sb)-containing wastewater; the behavior of Sb and mechanisms underlying precipitation were investigated by characterizing the precipitates. The results showed that the abiotic factors constraining SRB bacterial growth greatly affect Sb forms and precipitation. For instance, Sb precipitation maximumly occurred at pH 6 and 7, or C:N ratio of 10:1 and 40:3 for Sb(III) and Sb(V), respectively, resulting in a maximum Sb removal rate of 94%. Interestingly, we found that substantial antimonate and antimonite were adsorbed on the SRB cell surface, indicating that cell surface is a critical reaction site of Sb transformation and precipitation. Sb was adsorbed to the cell surface by C-C and C=O groups, and was further precipitated by forming Sb₂S₃ and Sb₂S₅ or was coprecipitated with the P-containing group. Partial Sb(V) reduction was also observed on the SRB cell surface. These results provided a deep insight into the Sb bio-transformation and were an advancement with respect to understanding bioremediation of Sb-contaminated wastewater. Full article

In this study, chitosan and iron-containing water treatment residues were used to prepare a chitosan/Fe-sludge particle adsorbent (CHFS) via the embedding method for Sb(III) removal. Various technologies were applied to characterize the CHFS, and batch experiments were used to investigate its adsorption properties. The results show that CHFS adsorbents are amorphous and have a specific surface area (119.95 m²/g), both beneficial for adsorption. pH and ionic strength have no impact on the adsorption. Sb(III) adsorption on CHFS occurs spontaneously and endothermically. Sb(III) adsorption by CHFS matches the pseudo-second-order kinetic model and the Langmuir model better, with a maximum adsorption capacity of 24.38 mg/g. The primary adsorption mechanism for Sb(III) is the inner sphere complexation between the Sb and Fe–O bond, while other adsorption mechanisms include chelation, pore filling, and hydrogen bonding. This study offers a reference for antimony removal and resource utilization of iron sludge. Full article

Effective wastewater treatment remains a critical challenge, especially when dealing with hazardous pollutants like antimony (Sb(III)). This study addresses this issue by using innovative nanocomposites to remove Sb(III) ions from water, while simultaneously repurposing the spent adsorbents for energy storage applications. We developed reduced graphene oxide-NiFe₂O₃-SiO₂-polyindole nanocomposites (RGO-NiFe₂O₃-SiO₂-PIn NCs) via a hydrothermal synthesis method, achieving a high removal efficiency of 91.84% for Sb(III) ions at an initial concentration of 50 mg/L at pH 8. After adsorption, the exhausted adsorbent was repurposed for energy storage, effectively minimizing secondary pollution. The Sb(III)-loaded adsorbent (RGO-NiFe₂O₃-SiO₂-PIn@SbO_x) exhibited excellent performance as an energy storage material, with a specific capacitance (C_s) of 701.36 F/g at a current density of 2 A/g and a retention rate of 80.15% after 10,000 cycles. This dual-purpose approach not only advances wastewater treatment technologies but also contributes to sustainable and economical recycling practices, particularly in the field of energy storage. Full article

This study introduces a series of Fe/Mn-GOCS composites using high-temperature impregnation with graphene oxide and chitosan as substrates, modified by diverse manganese salts, including MnCl₂∙4H₂O, KMnO₄, and MnSO₄. Among these, FeCl₂/MnSO₄-GOCS demonstrated the highest adsorption capacity for Sb(III), peaking at 57.69 mg/g. The adsorption performance was extensively evaluated under various conditions, such as different initial concentrations, pH levels, solid–liquid ratios, and adsorption durations. It was observed that when the Fe/Mn molar ratio exceeded 4:1, there was a notable decrease in both the adsorption capacity and removal rate. Kinetic analyses using the pseudo-second-order model revealed a better fit (R² > 0.99) compared to the pseudo-first-order model, indicating that chemisorption dominated the adsorption process. Additionally, isothermal modeling highlighted the efficiency of Fe/Mn-GOCS, particularly in high-concentration environments, with the Sips model demonstrating the best fit, integrating characteristics of both Langmuir and Freundlich models. These results not only offer a robust theoretical and practical basis for efficient Sb(III) removal but also underscore the potential of multi-metal-modified adsorbents as sustainable solutions for environmental remediation. Full article

Antimony (Sb) is one of the most concerning toxic metals globally, making the study of methods for efficiently removing Sb(III) from water increasingly urgent. This study uses graphene oxide and chitosan as the matrix (GOCS), modifying them with FeCl₂ and four MnO_x to form iron–manganese oxide (FM/GC) at a Fe/Mn molar ratio of 4:1. FM/GC quaternary composite microspheres are prepared, showing that FM/GC obtained from different MnO_x exhibits significant differences in the ability to remove Sb(III) from neutral solutions. The order of Sb(III) removal effectiveness is MnSO₄ > KMnO₄ > MnCl₂ > MnO₂. The composite microspheres obtained by modifying GOCS with FeCl₂ and MnSO₄ are selected for further batch experiments and characterization tests to analyze the factors and mechanisms influencing Sb(III) removal. The results show that the adsorption capacity of Sb(III) decreases with increasing pH and solid–liquid ratio, and gradually increases with the initial concentration and reaction time. The Langmuir model fitting indicates that the maximum adsorption capacity of Sb(III) is 178.89 mg/g. The adsorption mechanism involves the oxidation of the Mn-O group, which converts Sb(III) in water into Sb(V). This is followed by ligand exchange and complex formation with O-H in FeO(OH) groups, and further interactions with C-OH, C-O, O-H, and other functional groups in GOCS. Full article

In this study, following the concept of “treating waste with waste”, magnetic chitosan carbon (MCC) was developed through the pyrolysis of chitosan/iron sludge (CHS) beads created using an embedding method in a closed environment for antimony removal. The results indicate MCC has a good magnetic recovery rate and that its magnetic saturation strength can reach 33.243 emu/g. The iron proportion and acid resistance of MCC were all better than those of CHS, and at 25 °C, its adsorption saturation capacity improved from 24.956 mg/g to 38.234 mg/g. MCC has a quick adsorption equilibrium time, and in about 20 min, 90% of the final equilibrium capacity can be achieved. The primary mechanism of Sb adsorption by MCC is the formation of an inner sphere complex between Fe-O and Sb, while surface complexation, hydrogen bonding, and interaction also play a function. Thus, MCC, a lower-cost and greener adsorbent for Sb removal, has been made using iron sludge. This enabled it to utilize iron sludge as a resource and served as a reference for the sustainable management of water treatment residuals. Full article

Antimony and arsenic, which have a high carcinogenicity, should be removed depending on their ionic charge in water. Therefore, we attempted to confirm the adsorption characteristics of antimony and arsenic considering ionic charge to improve removal efficiency. We used palm-based activated carbon (PAC), coal-based activated carbon (CAC), modified activated carbon (MAC), styrene-divinylbenzene copolymer (SP825), activated alumina (AA), and zeolite as adsorbents for antimony and arsenic. Negatively charged adsorbents (CAC, PAC, MAC, and zeolite) with similar zeta potentials showed better removal efficiency as the surface area increased. However, SP825, which is almost neutral, and AA, which is positively charged, exhibited a high removal efficiency (100%) for arsenic and Sb(V), which are anions, regardless of surface area. However, due to the price, coal-based activated carbon or palm-based activated carbon is considered more advantageous than using AA or SP825. Last, during the arsenic adsorption process, As(III) was oxidized to As(V) due to Fe(II) contained in activated carbon. The addition of activated carbon can improve oxidation efficiencies of As(III) before coagulation and precipitation, in which As(V) is easier to remove than As(III). Full article

In this study, a renewable and reusable immobilized Microcystis aeruginosa microsphere loaded with magnetic Nano-Fe₃O₄ composite adsorbent material is designed to study the treatment of wastewater containing heavy metal Sb(III). Through static absorption experiments combined with various characterization methods, this article studies the absorption process and mechanism of Sb(III), and investigates the optimal preparation conditions and environmental influencing factors. The results show that the optimal preparation conditions for immobilized Microcystis aeruginosa microspheres loaded with magnetic Nano-Fe₃O₄ adsorbent materials are 50.0% mass fraction of Microcystis suspension, 1.5% mass fraction of Nano-Fe₃O₄, and 2.5% mass fraction of sodium alginate. When the pH of the solution is 4, the reaction temperature is 25 °C, and the adsorbent dosage is 8.5 g/L, the removal rate of Sb(III) is the highest, reaching 83.62% within 120 min. The adsorption process conforms to the pseudo-second order kinetic model and Langmuir adsorption isotherm model, mainly characterized by chemical adsorption and surface complexation. Therefore, the composite material has been proven to be an efficient Sb (III) adsorption material. Full article

The removal of harmful arsenic(V) from aqueous solutions using Cyanex 923 (solvation extractant) was investigated using various experimental variables: equilibration time, the acidity of the aqueous phase, temperature, extractant and arsenic concentrations, and O/A ratio. Cyanex 923 extracted As(V) (and sulfuric acid) from acidic solutions; however, it could not be used to remove the metal from slightly acid or neutral solutions. The extraction of arsenic is exothermic and responded to the formation of H₃AsO₄·nL species in the organic phase (L represents the extractant, and the stoichiometric factor, n = 1 or 2, depends on the acidity of the aqueous phase). Extraction isotherms are derived from the experimental results. Both arsenic and sulfuric acid loaded onto the organic phase can be stripped with water, and stripping isotherms are also derived from the experimental results. The selectivity of the system against the presence of other metals (Cu(II), Ni(II), Bi(III), and Sb(III)) is investigated, and the ability of Cyanex 923 to extract As(V) and sulfuric acid compared to the use of other P=O-based solvation reagents, such dibutyl butylphosphonate (DBBP) and tri-butyl phosphate (TBP), is also investigated. Full article