Soil dissolved organic matter (DOM) plays a pivotal role in governing the environmental behavior and fate of metal ions. The inherent heterogeneity of DOM, however, leads to complex and poorly understood interactions with heavy metals. In this study, soil DOM was fractionated into four pH-dependent fractions via PPL solid-phase extraction combined with sequential acid elution. The binding interactions of these fractions with Cu(II) were systematically investigated through and, coupled with two-dimensional correlation (2D-COS) analysis. The results indicated that low-pH fractions exhibited enhanced aromaticity and more pronounced spectral responses. Regardless of the DOM fraction, 2D-COS analysis revealed that short-wavelength chromophores (< 230 nm) preferentially coordinated with Cu(II), and the binding sequence of fluorescent components followed protein-like > fulvic-like > humic-like components. Moreover, functional group analysis showed that carboxyl C = O groups dominated the binding response, followed by aliphatic C-OH or phenolic O-H, while pH-based fractionation of DOM primarily influenced binding accessibility rather than binding mechanism. Meanwhile, the parallel factor analysis (PARAFAC) results revealed that protein-like substances exhibited higher conditional stability constants, whereas humic-like fractions provided more accessible binding sites among the pH-dependent DOM fractions. Collectively, these findings illuminated that the heterogeneous complexation mechanisms between DOM fractions and Cu(II), and provide a basis for assessing environmental geochemical risks of heavy metals.

The photocatalytic reduction of soluble U(VI) to insoluble U(IV) offers a promising strategy for uranium removal and recovery from radioactive wastewater. However, conventional sacrificial agents like methanol generate toxic byproducts and complicate uranium recovery. This study presents a highly efficient visible-light-driven photocatalytic system employing metal-free carbon quantum dots modified g-C3N4 (Cdots/CN) in conjunction with sulfite as a multifunctional sacrificial agent. The Cdots/CN composite was successfully synthesized via a facile calcination method and characterized by SEM, TEM, XPS, and Raman spectroscopy. Under optimized conditions, this synergistic photocatalytic system achieved a high U(VI) removal efficiency of 96.67% and retained over 92% efficiency across five consecutive cycles. As evidenced by control experiments, SO3 2- served dual roles as a hole scavenger and an oxygen consumer. Meanwhile, trapping experiments and electron paramagnetic resonance tests confirmed that SO3 center dot- and photogenerated electrons (e-) were the primary reactive species, with the SO3 center dot exhibiting dominance. XPS and XRD analyses verified the complete reduction of U(VI) to UO2 on the catalyst surface after reaction. This work not only demonstrates an effective photocatalytic strategy for uranium remediation but also highlights the superior performance of sulfite as a green alternative to conventional sacrificial agents, offering new insights for the design of sustainable wastewater treatment systems.

Soil dissolved organic matter (DOM) plays a pivotal role in governing the environmental behavior and fate of metal ions. The inherent heterogeneity of DOM, however, leads to complex and poorly understood interactions with heavy metals. In this study, soil DOM was fractionated into four pH-dependent fractions (pH 2, 3, 5, and 7) using PPL solid-phase extraction combined with sequential acid elution. The binding interactions of these fractions with Cu(II) were systematically investigated through fluorescence spectroscopy and Fourier transform infrared spectroscopies, coupled with two-dimensional correlation (2D-COS) analysis. The results indicated that low-pH fractions exhibited enhanced aromaticity and more pronounced spectral responses. Regardless of the DOM fraction, 2D-COS analysis revealed that short-wavelength chromophores (< 230 nm) preferentially coordinated with Cu(II), and the binding sequence of fluorescent components followed protein-like > fulvic-like > humic-like fraction. Moreover, functional group analysis showed that carboxyl C=O groups dominated the binding response, followed by aliphatic C-OH and phenolic O-H, while pH primarily influenced binding accessibility rather than binding mechanism. Among the pH-dependent DOM fractions, protein-like substances exhibited higher conditional stability constants, whereas humic-like fractions provide more accessible binding sites. Collectively, these findings illuminated that the heterogeneous complexation mechanisms between DOM fractions and Cu(II), and provide a spectroscopic basis for assessing environmental geochemical risks of heavy metals.

Phosphate-activation sequence has vital influence on the performance and mechanism of Cd(II) removal by biochar. Hence, the difference activation sequences (pyrolysis-impregnation, impregnation-pyrolysis and copyrolysis) were employed to produce K3PO4 activated sludge biochar to investigate the differences of Cd(II) sorption behavior and mechanism from aqueous solution. Compared to pristine sludge biochar (SBC) and pyrolysis-impregnation activated biochar (SBC-IB), the surface of impregnation-pyrolysis activated sludge biochar (SBC-IS) and co-pyrolysis activated sludge biochar (SBC-CS) exhibited rougher, more porous and higher graphitized. Compared to SBC (66.53 mg/g), SBC-IB (141.89 mg/g) and SBC-IS (175.34 mg/g), SBC-CS (262.39 mg/g) possessed the largest Cd(II) adsorption capacity at 303 K. The sorption mechanism could include complexation, precipitation, Cd(II)-pi interaction and cation exchange. By quantifying the mechanism contribution, pyrolysis-impregnation mainly improved complexation capacity, whereas impregnation-pyrolysis and co-pyrolysis primarily enhanced the contribution of precipitation and ion exchange. This work could provide a comprehensive guide for phosphate-activated biochar.

This study investigates the efficacy of activated carbon-nano-hydroxyapatite (AC-nHAP) gel microspheres, composed of sodium alginate and AC-nHAP, as permeable reactive barrier (PRB) fillers for electrokinetic remediation of uranium-contaminated soil. The optimum configuration with 3 g each of AC and nHAP achieved a uranium removal efficiency of 82.31

重金属污染土壤的修复是一项长期而艰巨的任务.作为化学修复的一种,钝化技术成本低、高效省时,而被广泛应用.从石灰性物质、含磷材料、黏土矿物、生物炭、其他材料五大方面归纳了钝化修复的种类,并介绍了钝化修复的作用机制,最后分析了钝化剂修复土壤中重金属的影响因素 ——钝化剂的投加量、pH、钝化剂的稳定性.基于目前研究现状以及钝化修复存在的问题,对钝化修复今后的发展趋势进行了展望.

Biochar is a solid product of biomass treated with pyrolysis or gasification, As a renewable resources adsorbent for water treatment, biochar will obtain better environmental benefits. The surface of biochar was modified by physical or chemical methods to improve its target application performance. The modification method of biochar adsorbent was described, the removal effect and mechanism of heavy metals in water by adsorbent were expounded, the effects of pH value of reaction system, reaction temperature and dosage of biochar adsorbent on the adsorption performance of biochar were analyzed, and the current research trends, prospects and research needs are also discussed.

The number and variety of solid wastes have increased as a result of socioeconomic growth and human activity,and resourcization of solid wastes has become a hot research topic at home and abroad.There is significant room for improvement in waste resourcization in the context of dual carbon,which emphasizes the growth of the circular economy.Treatment of uranium(Ⅵ)-containing radioactive wastewater,produced by the nuclear industry with a rapid advancement of nuclear technology,with adsorbent materials made of solid waste could achieve the goal of"treating waste with waste",alleviate environmental pollution issues and facilitate sustainable development.Herein,main solid waste adsorbents,such as agricultural and forestry solid waste,industrial solid waste and municipal solid waste that can be used for uranium removal were summarized,followed by introduction on the synthesis and modification methods of solid waste adsorbents as well as uranium removal mechanism.Finally,it was pointed out that the uranium adsorption materials should be developed in the direction of high efficiency adsorption,environmental protection and high added value.

本研究以南方某市北部化工区为研究对象,基于数值模拟软件(groundwater modeling system,GMS)建立水文地质概念模型和三维溶质运移数值模型,模拟期设定为2020 年1 月—2029 年 12 月,并对园区污染源污染物持续泄漏 1 h、12 h和 24h后,铊污染物在地下水中的迁移过程进行模拟预测.研究结果表明,Tl污染晕质量浓度为0.004～0.024 mg/L;污染晕核心区由污染源向东平移且呈扩张趋势,等值线质量浓度为0.012～0.016 mg/L,外圈区域整体向核心区收缩,等值线浓度为 0.008～0.012 mg/L;污染晕最大迁移距离分别为 363、1 085、2 753 m.超标范围为 0.07～1.04 km2,500 d和3 500 d 后相对于最初 50d 污染晕最大迁移距离分别延伸了66.5%和86.8%,污染晕核心区整体呈扩张趋势,外圈区域向核心区收缩.污染物持续泄漏 1 h、12 h 后和 24h 后随模拟时间延长呈线性上升趋势,最高值分别为0.02、0.005、0.003 5 mg/L.

通过对照实验?单因素实验及正交实验对铀污染土壤进行了电动优化修复研究.结果表明:0.20mol/L酒石酸与 0.05mol/L氯化铁复合电解液应用于改良装置修复后铀去除率提升至55.73%,铀平均浸出毒性浓度仅为0.07mol/L,且能量利用率增大至306.21.Visual MINTEQ软件模拟结果表明铀主要以带正电铀酰离子(UO22+)及少量中性铀-酒石酸络合物形式存在,因此,由于电迁移及正向电渗析的协同作用,铀的迁移方向为阳极到阴极.最后通过正交实验得出本实验最佳去除率的实验参数为0.15mol/L酒石酸和0.08mol/L氯化铁及1.5V/cm电压梯度.改良装置可通过提高土壤导电性、zeta电位、降低土壤 pH 值以提高修复效率,且酒石酸与氯化铁复合液作为电解液应用于改良装置修复铀污染土壤时能量利用率和去除率高,铀浸出毒性低.因此,酒石酸与氯化铁复合液应用于改良电动装置为铀污染土壤提供一种高效?绿色的原位修复技术.

从核污染出发,对深浅不同地质层的核迁移影响因素进行了分析,考虑了浓度和周围环境两个方面的影响,总结了可适用于不同地质层的天然迁移模型以及相对应的迁移机制,最后分析了各个模型存在的问题,并对模型进行了展望.

文章首先分析了高校硕士研究生科研创新能力现状,并对分层递阶理论进行了概述,接着论述了高校硕士研究生科研创新能力培养体系的构建和实施,然后对高校硕士研究生科研创新能力培养现状进行了问卷调查,最后提出了高校硕士研究生科研创新能力的提升措施.

综述了木质素在不同改性制备方法下的结构特点,阐述了不同结构下木质素特有的功能、形态,以及近年来国内外木质素类吸附剂反应机理和结构特点,重点介绍了官能团改性木质素材料、木质素碳材料及纳米木质素材料在重金属吸附方面的应用及研究.最后,总结了木质素基材料在处理重金属技术上存在的挑战,展望了该材料未来的发展方向,以期在实际应用中充分结合现实因素和各种改性方法的适用性,选择合适的木质素基材料来实现重金属的高效吸附去除.

以水热法制备了二元水滑石（MnAl-LDH）和三元水滑石（MnMgAl-LDH）,将其作为固定剂对U（Ⅵ）污染的土壤进行修复。利用毒性浸出实验（TCLP）和Tessier逐级化学提取法研究了固定前后铀的浸出特性与形态变化。结果表明，当含铀土壤不添加固定剂时，铀的浸出质量分数为147.20 mg/kg;当土壤中添加MnAl-LDH为固定剂培养28 d后，土壤中铀的浸出质量分数为44.16 mg/kg,浸出率为30.00%;投加MnMgAl-LDH培养28 d后，土壤中铀的浸出质量分数仅为31.90 mg/kg,浸出率降低至21.67%。

半导体、稀土开采等行业所排放的氟废水所引发氟中毒现象备受关注.吸附法是去除废水中氟离子的有效方法之一,但传统吸附剂存在吸附容量低、选择性差等缺点,亟需研发具有高吸附容量、可再生且无二次污染的吸附材料.本文归纳了一些新型吸附材料,如高分子材料吸附剂、生物炭、层状双氢氧化物、工业废弃物、纳米材料及其改性材料在含氟废水中的研究应用;总结了这些改性材料的制备过程,介绍了这些材料吸附除氟的能力,分析了新型吸附材料吸附除氟的机理以及共存离子干扰、pH适用范围等影响因素,并指出了材料制备存在的问题,提出了制备对氟离子具有高选择性能的改性吸附材料的发展方向和材料循环利用所需解决的重要问题.

随着工业的快速发展,电镀设备、采矿、纺织等行业排放的废水含有大量的重金属离子和有机污染物,这些污染物严重危害人类的身体健康.因此,如何快速有效地处理水体中的重金属离子和有机污染物是环境修复领域中亟待解决的问题.稻壳因具有来源广泛、可再生、环境友好等特点而被广泛应用于吸附材料和光催化材料领域.大量研究表明,稻壳能够去除污染水体中重金属离子和有机物的种类很多,但是对大多数污染物的去除能力不强,难以在实际应用中得到进一步推广.以稻壳为基体材料制备有高效去除能力的功能性材料,是近几年环境修复领域的研究热点.目前,研究者尝试以炭化、化学修饰等方式对稻壳改性,从而增大比表面积、孔隙率或者增加含氧官能团的数量,吸附性能也能随之改善,但是以上改性后的稻壳材料存在吸附能力弱和容易产生二次污染等问题.研究发现,负载Fe3 O4制备的磁性稻壳生物炭复合材料,不仅吸附性能强,且具有易分离、稳定性强、不会对环境造成二次污染等优点,这为稻壳基材料在实际应用的推广奠定了基础.另外,有研究报道,将稻壳中的SiO2作为半导体光催化剂(如TiO2、Ni2 O3)的载体可提高其光催化性能、回收利用率,使其在光学领域具有良好的使用性能.本文综述了稻壳材料本身的特性和改性稻壳制备稻壳基吸附剂的方法,讨论了稻壳基及其复合材料在水污染治理领域中作为吸附剂和光催化剂的应用.从不同类型的污染物角度出发,论述了稻壳基材料针对重金属离子、有机污染物处理过程中稻壳掺杂材料功能及体系作用机理的影响,还分析了影响污染物吸附的重要因素,最后对目前稻壳基材料在水治理领域应用进行了总结和对今后的研究方向做了展望.

金属有机框架化合物(MOFs)具有孔隙率高、比表面积大和化学性质稳定等优点,作为催化材料具有良好的发展前景.通过溶剂热法成功合成了g-C3N4/NH2-MIL-101(Fe)复合光催化剂.采用X-射线衍射仪(XRD)、扫描电子显微镜(SEM)及X射线光电子能谱(XPS)对催化剂的结构和表面形貌进行分析,并研究其在可见光(Vis)照射下活化过二硫酸盐(PDS)降解水中罗丹明B(RhB)的效果及活化机制.结果显示:g-C3N4/NH2-MIL-101(Fe)晶体结构完整、表面粗糙,并呈现出规则的正八面体结构;在可见光照射下,光催化剂投加量为0.2 g/L、PDS投加量为8 mmol/L、初始pH为3、温度为30℃时,反应50 min,RhB的去除率达到99％;HCO3-、H2PO4-、Cl-等阴离子能与活性基团反应,明显抑制体系对RhB的去除;3次循环后,g-C3N4/NH2-MIL-101(Fe)/PDS/Vis对RhB的去除率仍达到90％以上,表明g-C3N4/NH2-MIL-101(Fe)具有良好的稳定性.自由基猝灭实验表明,催化降解RhB的主要活性物种为h+、·OH和SO4·-,其作用大小为h+>·OH>SO4·-.

单原子催化剂(SACs)是一种将金属以原子态负载于载体上的新型材料,具有原子利用率高、催化活性强和易回收等优点,使其在催化降解有机污染物方面备受关注.本文介绍了 SACs的催化影响因素,总结了 SACs催化降解有机污染物在环境领域中的应用.此外,着重综述了不同过渡金属(Fe、Co、Mn、Cu等)单原子催化剂在基于双氧水或过硫酸盐的高级氧化技术中的催化机理,单原子金属(M)一般与N键合形成活性位点M—Nx,活化氧化剂生成自由基或单线态氧,高效降解有机污染物.最后,提出未来SACs在催化降解有机污染物的研究方向是合成金属负载量高、稳定性高、pH适用范围更广的SACs,以及根据SACs的结构-性能关系和催化机理,对目标污染物设计特定催化剂.

Uranium mining and smelting processes produce a large amount of low-concentration uranium wastewater, which endangers the ecological environment and human health. It is urgent to remove uranium (VI) from uranium-containing wastewater. In this study, UiO-66 and chitosan (CS) were used as raw materials to prepare UiO-66/CS new composite materials by cross-linking method. Through static adsorption experiments, different pH values, adsorbent dosage, adsorption time and initial uranium concentration were investigated. The influence of external factors on U(VI) removal rate. The UiO-66/CS material was characterized and analyzed by scanning electron microscopy (SEM), Fourier infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), etc., revealing the mechanism of adsorbent removal of U(VI). The results show that: when the initial uranium concentration is 5 mg/L, the temperature is 298 K, the pH is 5, the dosage is 0.15 g/L, and the adsorption time is 120 min, the removal rate of U(VI) by UiO-66/CS can reach 90.24%. The adsorption process conforms to the quasi-second-order kinetic model and Freundlich isotherm adsorption model. The adsorption and removal mechanism of U(VI) is mainly the complexation of —NH, —COOH, Zr—O,—OH and other functional groups with U(VI).

Uranium is a relatively active and chemically toxic natural radionuclide, its enrichment in the environment poses a serious threat to human health and ecosystems. It is necessary to dispose the uranium contaminated soil safely and efficiently. In this study, the effect of coal gangue-based geopolymers on the solidification of uranium-contaminated soil was examined using a single factor experiment. The highest compressive strength of the solidified body reached 24.6 MPa, and the highest fixation efficiency of uranium reached 77.44%. The results show that lower liquid-to-solid ratio, higher alkali activator content and lower alkali activator modulus promote the solidification of uranium.