In the past 10 years, the treatment and restoration of soil and water bodies contaminated by mercury and other heavy metals have received unprecedented attention and support from China's environmental protection authorities. The search for low-cost and high-efficiency adsorbents has become one of the research hotspots in this field. In this paper, a simple and environment-friendly method was used to graft 3-mercaptopropyl trimethoxysilane on the surface of palygorskite. The synthesized mercaptofunctionalized palygorskite (M-PAL) was characterized by XRD, FT-IR, BET and SEM-EDS, respectively, and its adsorption conditions, adsorption models and thermodynamic parameters for Hg were systematically investigated. The experimental results indicated that the saturated adsorption capacity of Hg on the M-PAL could reach 203.4 mg·g, within 120 min at pH 4 and 298 K. By analyzing the experimental data of adsorption kinetics and thermodynamics, it was found that the adsorption process of Hg conformed to the pseudo-second-order kinetic model, which belonged to chemical adsorption of the rate-controlled step; the Langmuir model better described the adsorption isotherm. The thermodynamic parameters obtained (ΔH=29.95 kJ·mol, ΔS=103.09 J·mol·K and ΔG<0) show that the whole process is a spontaneous endothermic process. When the concentration of Na, K, Ca, Mg, Cl, NO, HCO and CHO was 200 times that of Hg, although these organic acids had a slightly greater effect on the adsorption of Hg on mercaptofunctionalized palygorskite than inorganic ions, the adsorption capacity remained above 185 mg·g. The adsorption products could be still stable in simulated acid rain with pH 3, 4, 5, 6, 7 and oxalic acid solution with concentration of 1, 2, 3, 4 and 5 mmol·L, and the desorption rates were about 3%. Through XPS analysis, the specific coordination of Hg with the S atom on the surface of M-PAL was confirmed.
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http://dx.doi.org/10.1007/s11356-021-15637-0 | DOI Listing |
Environ Res
December 2024
College of Materials Science and Engineering, Fuzhou University, Fuzhou 350116, PR China. Electronic address:
This work developed a novel oxidized hierarchical porous carbon (OHPC) with vesicule-like ultrathin graphitic walls via a method of air oxidation and used as an efficient adsorbent for Congo red (CR) and Malachite green (MG) removal. Results show that the OHPC2 oxidized at 400 °C possesses three-dimensional hierarchical pores with vesicule-like ultrathin graphitic walls. The prepared OHPC2 not only has a large specific surface area of 1020 m g with a high pore volume, but also has abundant oxygen-containing functional groups.
View Article and Find Full Text PDFEnviron Res
December 2024
State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China; State Environmental Protection Key Laboratory of Synergetic Control and Joint Remediation for Soil& Water Pollution, College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, China.
To develop an efficient and cost-effective adsorbent for phosphate removal from water bodies, this study utilized natural red clay (RC) as a carrier. The modified red clay (MRC) was prepared through three methods: acid modification, high-temperature calcination, and metal loading. The preparation conditions were optimized, and the adsorption effects on phosphate were compared across these different modifications.
View Article and Find Full Text PDFChemosphere
December 2024
College of Land Science and Technology, China Agricultural University, Beijing 100193, PR China. Electronic address:
Heavy metals released from metallic sulfidic tailings pose significant environmental threats by contaminating surface and groundwater in mining areas. Sustainable rehabilitation methods are essential to remove or stabilize these metals, improving the quality of acid mine drainage and minimizing pollution. This study examines the adsorption capacity of zinc ions (Zn) by different iron-silicate mineral groups under natural weathering and bacteria-regulated weathered conditions.
View Article and Find Full Text PDFChemosphere
December 2024
Department of Civil, Environmental and Ocean Engineering, Stevens Institute of Technology, 1 Castle Point Terrace, Hoboken, NJ, 07030, USA. Electronic address:
Phosphate (PO(III)) contamination in water bodies poses significant environmental challenges, necessitating efficient and accurate methods to predict and optimize its removal. The current study addresses this issue by predicting the adsorption capacity of PO(III) ions onto biochar-based materials using five probabilistic machine learning models: eXtreme Gradient Boosting LSS (XGBoostLSS), Natural Gradient Boosting, Bayesian Neural Networks (NN), Probabilistic NN, and Monte-Carlo Dropout NN. Utilizing a dataset of 2952 data points with 16 inputs, XGBoostLSS demonstrated the highest R (0.
View Article and Find Full Text PDFChemosphere
December 2024
Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 81148, Taiwan. Electronic address:
Visible light photocatalysts hold great promise for water purification, yet research on highly efficient, non-toxic photocatalysts is limited. This study synthesized novel g-CN/AlOOH photocatalytic nanocomposites via thermal condensation, enhancing adsorption and visible light degradation by 36-fold and 11-fold, respectively, compared to g-CN alone. The nanocomposites achieved a 98% removal rate of methyl orange under xenon lamp irradiation (>400 nm) for 1 hour.
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