Carbon-Based Materials for Pollutant Immobilization and Removal in Soil and Water

A special issue of Toxics (ISSN 2305-6304). This special issue belongs to the section "Toxicity Reduction and Environmental Remediation".

Deadline for manuscript submissions: 30 June 2025 | Viewed by 2947

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Guest Editor
Department of Environmental Science and Engineering, School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing 400074, China
Interests: distribution of microplastic in environment; migration of microplastics; environmental behavior of heavy metals
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Special Issue Information

Dear Colleagues,

Many hazardous chemicals, which are persistent, bioaccumulative, carcinogenic, and mutagenic and have reproductive toxicity, can enter the soil and water environment and pose potential environmental and health risks.

The immobilization and removal of pollutants in soil and water play very important roles in pollution treatment. The processes that control the fate and distribution of heavy metals and organic pollutants in the environment, include several fundamental physical, chemical, and biological processes. The immobilization and removal of the pollutants means preventing them from entering the biological chain. Thus, the immobilization and removal of toxic pollutants from soil and water environments has been the focus of research.

Carbon-based materials, including activated carbon, graphene, carbon nanotubes, carbon nanofibers, biochar, and carbon aerogels, were widely studied for pollutant immobilization and removal in soil and water due to their good adsorption properties. However, sustainable and carbon-neutral materials are still needed to investigate the immobilization and removal of toxic pollutants in soil and water.

Therefore, in this Special Issue, titled “Carbon-Based Materials for Pollutant Immobilization and Removal in Soil and Water”, we will accept excellent research that addresses one or more of the following topics: carbon-based materials, emerging pollutants, heavy metals, immobilization, and removal.

Prof. Dr. Jianxin Fan
Guest Editor

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Keywords

  • carbon-based materials
  • emerging pollutants
  • heavy metals
  • immobilization
  • removal

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Published Papers (3 papers)

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Research

15 pages, 1242 KiB  
Article
Efficient Adsorption of Lead on Hydro-Pyrochar Synthesized by Two-Step Conversion of Corn Cob in Magnesium Chloride Medium
by Marija Simić, Jelena Petrović, Marija Koprivica, Marija Ercegović, Jelena Dimitrijević, Nikola S. Vuković and Núria Fiol
Toxics 2025, 13(6), 459; https://doi.org/10.3390/toxics13060459 - 30 May 2025
Viewed by 222
Abstract
This study used widely available waste biomass, corn cob (CC), to remove Pb ions from aqueous solutions. A two-step conversion of this material was carried out to improve its adsorption characteristics. Firstly, CC was prepared by hydrothermal carbonization; afterward, the obtained hydrochar was [...] Read more.
This study used widely available waste biomass, corn cob (CC), to remove Pb ions from aqueous solutions. A two-step conversion of this material was carried out to improve its adsorption characteristics. Firstly, CC was prepared by hydrothermal carbonization; afterward, the obtained hydrochar was doped by MgCl2 and pyrolyzed. The synthesized hydro-pyrochar (HCC-Mg) was used for adsorption experiments in a batch system. The surface and structural properties of HCC-Mg were characterized by SEM-EDX and FTIR analysis before and after Pb adsorption. Kinetic and isotherm models were applied to the experimental results. It was confirmed that Pb adsorption on HCC-Mg occurred rapidly, with a maximum adsorption capacity of 87.08 mg/g. The pseudo-second-order model best described the adsorption process, while the best fit of the experimental data was observed with the Sips isotherm model. The results of this study showed that the capacity of the synthesized HCC-Mg material had increased more than 14 times compared with raw CC. In addition, the synthesized material had the potential to be reused for at least five cycles with minimal loss of adsorption capacity and efficiency. Moreover, the results confirmed that HCC-Mg can be used as an efficient, sustainable adsorbent of Pb from polluted water. Full article
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16 pages, 2135 KiB  
Article
Synergistic Effects of Unmodified Tea Leaves and Tea Biochar Application on Remediation of Cr-Contaminated Soil
by Weili Qi, Yun Yang, Yan Xu, Xiaowen Teng, Jiawei Ma, Weijie Xu, Zhengqian Ye, Xianzhi Fang and Dan Liu
Toxics 2024, 12(12), 888; https://doi.org/10.3390/toxics12120888 - 6 Dec 2024
Cited by 1 | Viewed by 973
Abstract
Hexavalent chromium (Cr(VI)) contamination in soil presents significant risks due to its high toxicity to both the environment and human health. Renewable, low-cost natural materials offer promising solutions for Cr(VI) reduction and soil remediation. However, the effects of unmodified tea leaves and tea-derived [...] Read more.
Hexavalent chromium (Cr(VI)) contamination in soil presents significant risks due to its high toxicity to both the environment and human health. Renewable, low-cost natural materials offer promising solutions for Cr(VI) reduction and soil remediation. However, the effects of unmodified tea leaves and tea-derived biochar on chromium-contaminated soils remain inadequately understood. In this study, tea tree pruning waste was converted into biochar at various temperatures, and the impacts of both unmodified tea leaves and tea biochar on soil Cr(VI) content, chromium fractionation, and soil biochemical properties were assessed using a soil incubation experiment. The results showed that the combined treatment of tea and tea biochar produced at 500 °C reduced Cr(VI) content by up to 49.30% compared to the control. Chromium fractionation analysis revealed a significant increase in the residual chromium fraction, accounting for 32.97% of total chromium, substantially reducing its bioavailability and mobility. Soil properties were markedly improved, with notable increases in pH (14.89%), cation exchange capacity (CEC; up to 100.24%), and organic matter content (up to 167.12%) under the combined treatments. Correlation analysis confirmed that Cr(VI) content reductions were positively correlated with increases in pH, nutrient retention, and enzyme activities, highlighting their role in chromium stabilization. This study underscores the synergistic potential of unmodified tea leaves and tea biochar as an innovative, eco-friendly strategy for Cr(VI) remediation, enhancing both soil quality and heavy metal stabilization. Full article
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21 pages, 10722 KiB  
Article
The Mechanism of Arsenic Release in Contaminated Paddy Soil with Added Biochar: The Role of Dissolved Organic Matter, Fe, and Bacteria
by Jianxin Fan, Maoyu Liao, Ting Duan, Ying Hu and Jiaoxia Sun
Toxics 2024, 12(9), 661; https://doi.org/10.3390/toxics12090661 - 10 Sep 2024
Viewed by 1325
Abstract
The addition of biochar inevitably modifies the acidity (pH), redox potential (Eh), and dissolved organic matter (DOM) level in the soil. These alterations also have coupled effects on the cycling of iron (Fe) and the composition of bacterial communities, thereby impacting the speciation [...] Read more.
The addition of biochar inevitably modifies the acidity (pH), redox potential (Eh), and dissolved organic matter (DOM) level in the soil. These alterations also have coupled effects on the cycling of iron (Fe) and the composition of bacterial communities, thereby impacting the speciation and availability of arsenic (As) in the soil. This study explored the potential mechanisms through which biochar affects As in paddy soil during flooded cultivation with different pyrolysis temperature biochars (300 °C, 400 °C, and 500 °C) added. The results revealed that the TAs concentration increased in the initial 15 days of soil cultivation with SBC300 or SBC400 addition because increasing the concentration of DOM induced the mobility of As though the formation of As-DOM complexes. Meanwhile, biochar addition elevated the pH, decreased the Eh, and promoted the transformation of specific adsorbed As (A-As) and amorphous iron oxide-bound As (Amo-Fe-As) to supernatant As through enhancing the reductive dissolution of Fe(oxy)(hydr)oxides. Moreover, the biochar altered the relative abundance of As (V)-reducing bacteria (such as Firmicutes) and As (III)-oxidizing bacteria (such as Chloroflex), thereby affecting As speciation. However, these mechanistic effects varied depending on the pyrolysis temperature of the biochar. The microbial composition of SBC300 and SBC400 were similar, with both containing larger populations of Enterobacteriaceae (AsRB) and pseudomonas (FeRB) compared to CK and SBC500. It was proposed that lower pyrolysis temperatures (300 °C and 400 °C) are more favorable for the dissolution of Fe(oxy)(hydr)oxides and the reduction of As (V). However, the biochar from the higher pyrolysis temperature (500 °C) showed environmental impacts akin to the control group (CK). This study demonstrated potential mechanisms of biochar’s effect on As and the role of pyrolysis temperature. Full article
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