Key Takeaways & Executive Findings
- •• • SH-Ti3C2Tx achieved an adsorption capacity of 55.6 mg·g−1 for As(III) at pH 7, 2.8 times higher than pristine Ti3C2Tx (20 mg·g−1), enabling more efficient removal in high-load scenarios. • • The adsorption process followed the Langmuir isotherm and pseudo-second-order kinetics, confirming monolayer chemisorption via As–S bond formation, which ensures strong binding and stability. • • The SH-Ti3C2Tx@MS flow-through column achieved 99.5% removal of As(III) from both 100 μg·L−1 and 100 mg·L−1 solutions, consistently reducing concentrations below the WHO standard of 10 μg·L−1. • • Regeneration with 1 mol·L−1 NaOH allowed five consecutive adsorption–desorption cycles while maintaining >80% removal efficiency, demonstrating operational reusability and cost-effectiveness.
Abstract
A thiol-functionalized Ti3C2Tx (SH-Ti3C2Tx) material was synthesized via chemical bonding of dithiothreitol (DTT) onto Ti3C2Tx MXene for the adsorptive removal of As(III) from water. Characterization by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) confirmed a typical two-dimensional layered structure with DTT covalently attached. The adsorption of As(III) on SH-Ti3C2Tx followed the Langmuir isotherm model, indicating monolayer adsorption. At pH 7, the maximum adsorption capacity reached 55.6 mg·g−1, which is 2.8 times higher than that of pristine Ti3C2Tx (20 mg·g−1). X-ray photoelectron spectroscopy (XPS) revealed that As(III) uptake primarily occurred via formation of As–S bonds. To enable continuous treatment, SH-Ti3C2Tx was loaded onto melamine sponge via electrostatic interactions to fabricate a flow-through adsorption column (SH-Ti3C2Tx@MS). This column achieved removal efficiencies of 99.5% for both high (100 mg·L−1) and low (100 μg·L−1) As(III) concentrations, reducing effluent As(III) to below the World Health Organization guideline of 10 μg·L−1. The spent column could be regenerated using 1 mol·L−1 NaOH solution, retaining over 80% of its initial removal efficiency after five consecutive adsorption–desorption cycles. The SH-Ti3C2Tx material demonstrates significant potential for efficient and reusable removal of As(III) from contaminated waters.
1. Introduction
Arsenic contamination in groundwater poses a severe public health threat, with chronic exposure linked to cancers and cardiovascular diseases. The World Health Organization has set a stringent guideline of 10 μg·L−1 for total arsenic in drinking water. Among arsenic species, As(III) is notably more toxic (approximately 60 times) than As(V) and is notoriously difficult to remove using conventional methods such as precipitation and membrane filtration, which are often ineffective or energy-intensive. This technological gap necessitates the development of adsorbents that can directly and selectively capture As(III) from aqueous environments.
Two-dimensional MXenes, particularly Ti3C2Tx, have emerged as promising adsorbent platforms due to their high surface area, hydrophilic nature, and tunable surface chemistry. However, pristine Ti3C2Tx exhibits limited affinity for As(III), with a reported capacity of only 20 mg·g−1. To address this bottleneck, we functionalized Ti3C2Tx with dithiothreitol (DTT) to introduce thiol (–SH) groups, which are known to form strong complexes with arsenic. This surface engineering not only enhances adsorption capacity but also provides a scalable route for fabricating flow-through adsorption columns, offering a practical solution for continuous water treatment.
Loading authentic research manuscript (Pages 1–5)...
ZHAO Zhanyi, LIU Jinghua, TAN Feng (2026). Sulfhydryl Functionalized Two-Dimensional Ti3C2Tx MXene for Capture of As(III) in Aqueous Solution. Environmental Chemistry. https://doi.org/10.7524/j.issn.0254-6108.2025032006
Research & Educational Purpose Only: The translations, structured abstracts, analytical annotations, and data reports provided by SinoGreenTechare intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoGreenTech claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is the maximum adsorption capacity of SH-Ti3C2Tx for As(III) and how does it compare to pristine Ti3C2Tx?
The maximum adsorption capacity of SH-Ti3C2Tx for As(III) at pH 7 is 55.6 mg·g−1, which is 2.8 times higher than that of pristine Ti3C2Tx (20 mg·g−1). This enhancement is attributed to the introduction of thiol groups that form strong As–S bonds, as confirmed by XPS.
How does the SH-Ti3C2Tx@MS column perform under continuous flow conditions for both high and low As(III) concentrations?
The SH-Ti3C2Tx@MS column achieved removal efficiencies of 99.5% for both high (100 mg·L−1) and low (100 μg·L−1) As(III) concentrations. Effluent concentrations were consistently below the WHO guideline of 10 μg·L−1, demonstrating its effectiveness across a wide concentration range.
What is the regeneration protocol and how does the material perform over multiple cycles?
Regeneration is performed using 1 mol·L−1 NaOH solution. After five consecutive adsorption–desorption cycles, the removal efficiency remained above 80% of the initial capacity, indicating good reusability and operational stability.
What is the adsorption mechanism of As(III) on SH-Ti3C2Tx?
The adsorption mechanism involves chemisorption via formation of As–S bonds between As(III) and the thiol groups on the functionalized MXene surface. This is supported by XPS analysis and the fit to the Langmuir isotherm and pseudo-second-order kinetic model, indicating monolayer chemical adsorption.
What are the potential scalability and cost implications of using SH-Ti3C2Tx for large-scale water treatment?
The synthesis involves simple chemical functionalization of Ti3C2Tx with DTT, which is relatively low-cost. The material can be loaded onto melamine sponge to create a flow-through column, facilitating scale-up. The high removal efficiency and reusability over multiple cycles reduce operational costs, making it a viable option for point-of-use or community-scale treatment systems.
Related Chinese Research & Cross-Citations
Exploring the Potential Molecular Mechanisms of Eight Environmental Pollutants in Lung Adenocarcinoma through Network Toxicology, Machine Learning, and Multi-Omics Analysis
Epidemiological studies have established a significant association between exposure to environmental pollutants (EP) and the risk of lung adenocarcinoma (LUAD). This study integrates network toxicology and multi-omics analysis to elucidate the EP-LUAD molecular regulatory network and identify key regulatory genes, thereby revealing novel mechanisms of environmental carcinogenesis. Transcriptomic data from GEO and TCGA databases yielded 4,971 and 4,488 disease-related targets, respectively. Integration of toxicology databases (TargetNet, Swiss Target Prediction, CTD, SEA) identified 24,860 potential targets for eight common pollutants (SO2, NO, CO, NO2, O3, benzene, toluene, and polycyclic aromatic hydrocarbons). Intersection of these datasets produced 1,536 EP-LUAD common target genes. Protein-protein interaction network analysis identified 247 core targets. Machine learning selected five key genes: AGER, CAV1, CD44, CEP55, and GNB3, which demonstrated robust diagnostic and prognostic efficacy. Their expression correlated with immune cell infiltration, including CD4+ memory T cells and macrophages. Single-cell RNA sequencing revealed epithelial cell-specific expression patterns. Molecular docking confirmed stable pollutant-target binding, with PAH showing highest affinity for CD44 (binding energy −9.32 kcal·mol−1) and GNB3 (−8.32 kcal·mol−1). These findings establish AGER, CAV1, CD44, CEP55, and GNB3 as core molecular mediators of pollution-related LUAD. The high-affinity binding of PAH to CD44 and GNB3 underscores its carcinogenic potential. This study constructs a multi-level regulatory network for EP-LUAD, revealing underlying molecular mechanisms and providing novel potential targets and theoretical basis for early warning and intervention.
Effects of Different Functionalized Nanoplastics on the Transformation of Extracellular Antibiotic Resistance Genes in Aquatic Environments
The rapid dissemination of antibiotic resistance genes (ARGs) in aquatic environments poses serious threats to public health and environmental safety under the 'One Health' framework. Nanoplastics (NPs), as co-occurring pollutants, can exacerbate ARG risks by promoting horizontal gene transfer (HGT), yet the influence of different functional groups on extracellular ARG (eARG) transformation remains unclear. This study investigated the effects of carboxy-modified polystyrene NPs (PS-COOH) and amino-functionalized polystyrene NPs (PS-NH2) compared to unmodified polystyrene NPs (PS) on the transformation of the extracellular resistance plasmid IE-V1955 (carrying an ampicillin resistance gene) into Escherichia coli DH5α. Results showed that PS-COOH exposure promoted plasmid transformation similarly to PS, with effects increasing over 0.1–20 mg·L−1. Low concentrations (0.1–0.5 mg·L−1) of PS-NH2 also enhanced transformation, with stronger effects than PS-COOH at equal doses, whereas high concentrations (1–20 mg·L−1) inhibited it. Mechanistically, PS-COOH (0.1–20 mg·L−1) and low PS-NH2 induced intracellular reactive oxygen species (ROS), increased cell membrane permeability, elevated the protein-to-polysaccharide ratio in extracellular polymeric substances (EPS), and promoted biofilm formation, thereby facilitating transformation. High PS-NH2 concentrations caused excessive ROS leading to cell lysis and formed aggregates with plasmids larger than membrane pores, blocking uptake. These findings provide a theoretical basis for assessing the combined environmental health risks of NPs and ARGs.
Cardiovascular Toxicity Induced by Micro/Nano-Plastics and Its Mechanisms
Micro/nano-plastics (MNPs) are emerging contaminants widely detected in human circulatory systems, including blood, heart, and vascular endothelium, raising concerns about cardiovascular health risks. This systematic review analyzed 61 peer-reviewed studies (2008–2024) to elucidate the cardiotoxic effects and molecular mechanisms of MNPs. Evidence indicates that MNPs exposure elevates risks of atherosclerosis, thrombosis, and arrhythmias through oxidative stress, inflammatory cascades, endothelial dysfunction, and metabolic dysregulation. Notably, co-exposure with persistent organic pollutants (POPs) or heavy metals may produce synergistic or antagonistic effects. Current research relies predominantly on animal and cell models, with critical gaps in low-dose, long-term exposure data and epidemiological evidence. Future studies should optimize experimental designs, integrate metabolomics and epigenetics, and explore transgenerational effects and combined toxicity mechanisms to inform pollution control policies and mitigate cardiovascular risks.
Body Burden of Polybrominated Diphenyl Ethers and Joint Effects on Thyroid Function in a Physical Examination Population in Shenzhen
This study characterized the body burden of polybrominated diphenyl ethers (PBDEs) in a physical examination population in Shenzhen and evaluated its impact on thyroid function. Serum samples from 368 residents were analyzed for eight PBDE congeners using atmospheric pressure gas chromatography-tandem mass spectrometry (APGC-MS/MS). The median concentration of ∑8PBDEs was 10.2 ng·g⁻¹ lipid weight (lw), ranging from 0.13 to 2089.4 ng·g⁻¹ lw, with BDE-209 predominating (59.7% of total). Multiple linear regression revealed that a 1.7-fold increase in serum BDE-153 was associated with a 0.4% increase in free triiodothyronine (FT3) (P<0.05), while a 1.7-fold increase in BDE-183 was associated with a 0.9% decrease in total triiodothyronine (T3) and a 0.7% decrease in FT3 (P<0.05). Bayesian kernel machine regression (BKMR) indicated a negative correlation between mixed PBDE exposure and thyroid-stimulating hormone (TSH) at high exposure levels. Weighted quantile sum (WQS) regression showed that mixed exposure was associated with decreased T3 levels and T3/FT3 ratio, with BDE-153 and BDE-183 as the primary contributors. These findings suggest that PBDE exposure may adversely affect thyroid function and disrupt thyroid hormone homeostasis, with BDE-183 and BDE-153 playing key roles. This study provides a scientific basis for PBDE health risk assessment and thyroid protection.
Mechanisms of Natural Organic Matter in Regulating Microplastic Aggregation and Transport in Soil-Groundwater Systems: A Review
Microplastics (MPs) are persistent emerging contaminants ubiquitously distributed in soil-groundwater environments, where their aggregation and transport critically govern pollutant fate and ecological risks. Natural organic matter (NOM), a complex assemblage of organic compounds, interacts with MPs and porous media via hydrogen bonding, π-π interactions, hydrophobic effects, and electrostatic binding, thereby modulating MP surface properties and environmental behavior. This review systematically synthesizes the mechanisms by which NOM influences MP aggregation and transport, with emphasis on the distinct roles of humic substances, proteins, and extracellular polymeric substances (EPS), and their synergistic modulation with solution chemistry (pH, ionic strength, ion type). Additionally, NOM accelerates MP aging and alters surface characteristics, consequently impacting transport capacity. Current research limitations are identified, and future directions are proposed to inform MP pollution risk assessment and management strategies. Key findings indicate that NOM generally enhances MP stability and mobility at low ionic strengths, while high ionic strengths may induce aggregation depending on NOM type and ion valence. Humic substances predominantly increase electrostatic repulsion, whereas proteins and EPS can bridge particles, promoting aggregation. Aging processes, accelerated by NOM photochemical activity, increase surface oxygen functionality and hydrophilicity, further altering transport. The review underscores the need for systematic studies under environmentally relevant conditions to predict MP fate accurately.
Neurotoxicity of Carboxyl-Modified Polystyrene Microplastics on Zebrafish at Early Developmental Stage
Carboxyl-modified polystyrene microplastics (PS-COOH) are negatively charged particles formed by surface oxidation and functional group modification of polystyrene microplastics (PS), widely used in biomedical and analytical chemistry. However, studies on their neurotoxic effects on aquatic organisms are scarce. This study employed zebrafish (Danio rerio) as a model organism, exposing embryos to environmentally relevant concentrations (0.1, 1, 10, 100 μg·L−1) of PS and PS-COOH. Neurotoxic effects were assessed by measuring tail coiling frequency at 24 hpf and swimming velocity under alternating light/dark cycles at 120 hpf. Results demonstrated that both PS and PS-COOH induced neurotoxicity, with PS-COOH significantly reducing tail coiling frequency and average swimming speed compared to PS (P<0.05). Exposure to 10 μg·L−1 PS-COOH disrupted neurotransmitter homeostasis, altering levels of acetylcholine (ACh), serotonin (5-HT), and γ-aminobutyric acid (GABA). Transgenic zebrafish Tg(huc:EGFP) fluorescence assays revealed that PS-COOH (0.1–100 μg·L−1) caused damage to central neurons. These findings indicate that PS-COOH exposure impairs cholinergic, serotonergic, and GABAergic neurotransmission, induces neuronal damage, and exerts neurotoxic effects on zebrafish larvae. This study provides a theoretical basis for assessing the ecological and health risks of modified microplastics.