过渡金属活化过硫酸盐在环境修复领域的研究进展

近年来基于硫酸根自由基的高级氧化技术被广泛应用于环境修复.过硫酸盐作为硫酸根自由基的前体物质,通过活化过硫酸盐产生高活性的硫酸根自由基,可以高效降解有机污染物.伴随着大量不同种类的过渡金属活化材料被先后研究应用,新的过渡金属活化过硫酸盐去除有机污染物的机制被不断发现,比如常见的过渡金属活化过硫酸盐产生自由基的自由基机制...     

碳源补充型高级氧化法工艺净化水中磺胺类抗生素研究进展与趋势

磺胺类抗生素(SAs)是自然水环境和污水处理系统中检出频次与残留浓度最高的抗生素之一。过氧乙酸(PAA)作为广谱性杀菌剂,因其氧化性强、环境友好等优势,其用于有机污染物降解成为研究热点之一。与传统H2O2基芬顿法等无机氧化法相比,PAA氧化反应生成乙酸,经中和后转化的乙酸钠可为后续生化工艺段提供优质碳源,有效降低含SAs废水的处理成本。该文对PAA基碳源补充型高级氧化法的研究进展与趋势进行了系统总结。以SAs作为典型水环境污染物,对近年来PAA基碳源补充型高级氧化工艺进行了系统总结分析,比较分析了其对各类水质背景中SAs的去除效能,并对过渡金属、碳基材料等多种PAA活化方式,工艺运行参数、活性氧物种(ROS)的交联作用机理以及SAs降解机制进行了剖析。研究发现,乙酰氧基自由基和乙酰过氧基自由基为PAA基高级氧化工艺中的基础活性物质,pH、PAA含量、共存物质等会不同程度上影响体系中ROS的生成路径。此外,磺胺类抗生素主要包括五元磺胺和六元磺胺,二者降解机理存在一定差异。五元磺胺降解主要依靠苯胺环上氨基氧化、羟基取代、S–N/S–C键断裂、N中心自由基偶联反应等4种途径;六元磺胺降解过程...     

含氮有机污染物在超临界水氧化(SCWO)中去除的QSAR模型

超临界水氧化(SCWO)作为一项高效的去除水体中有机污染物的技术已得到了广泛的应用.为了更好地理解含氮有机物污染物在SCWO中总氮(TN)去除的规律,本研究以定量构效关系(QSAR)模型为方法,构建了41种含氮有机污染物在SCWO中TN％与有机污染物分子量子化学参数之间的QSAR模型.其最优QSAR模型结果为TN％=8...     

热活化过硫酸钠氧化去除水中邻苯二甲酸酯

邻苯二甲酸酯(PAEs)主要用作塑料产品制造和加工的增塑剂,是全球关注的新兴污染物之一.本研究以邻苯二甲酸(2-乙基己基)酯(DEHP)和邻苯二甲酸二丁酯(DBP)为目标污染物,研究了在不同污染物初始浓度、过硫酸钠活化温度及浓度、助溶剂添加量对过硫酸钠氧化去除水中邻苯二甲酸酯的影响及机理.结果表明,在实验条件下,邻苯二甲酸酯初始浓度与去除率呈反比,反应温度、过硫酸钠浓度和pH与邻苯二甲酸酯的去除率呈正比.在80℃,过硫酸钠浓度为84 mmol·L^-1,助溶剂的添加量为30%时,DBP的降解率达到了100%,DEHP的降解率达到了92.8%. GC/MS分析表明,在高温活化过硫酸钠的条件下,邻苯二甲酸和邻苯二甲酸酐是DBP降解的主要产物,脱烷基化和羟基化是DBP降解的主要机理.本研究为过硫酸钠去除环境介质中的邻苯二甲酸酯提供了理论和实践依据.     

过硫酸盐的活化及其在氧化降解水中抗生素的机理和应用

抗生素是一类用于阻止和治疗微生物传染性疾病的人用和兽用药物,在人类和动物疾病治疗领域以及水产养殖业有着广泛的用途.近年来,抗生素作为一种新型污染物不断排入水体并且在水体中持续存在,对水生态环境以及人类健康造成了威胁.基于硫酸根自由基（SO·4-）的高级氧化技术因其快速高效、适用范围广等特点,其在处理抗生素废水已经成为国内外研究热点.本文综述了近年来国内外利用UV、热、过渡金属、金属氧化物、零价金属、碳基材料、有机物、组合方式等常规及新型活化方法活化过硫酸盐以及处理抗生素废水的研究进展,并讨论了不同活化方式对抗生素的降解效率及机理的影响,最后展望了过硫酸盐高级氧化技术应用于抗生素降解的研究方向和挑战.     

固定化微生物技术在富营养化水体修复中的应用

富营养化不仅影响水环境质量,而且破坏水生态平衡,对环境和人类健康造成危害。固定化微生物技术是利用物理或化学方法将游离微生物细胞限制在一定空间区域内,既能免受流水冲刷流失,可重复循环利用,又能保持生物活性,有效去除水体中的污染物,因此该技术被认为是控制水体富营养化的有效方法。该研究介绍了固定化微生物技术的特点及其在富营养化水体处理中的应用现状,综述了传统及新型固定化载体的选择及发展、降解和去除氮磷污染物的微生物种类以及常用固定化方法(吸附、包埋、共价结合、交联等)的优缺点。最后,针对当前微生物固定化技术面临的挑战,对今后的研究和发展方向提出了建议。该综述可为固定化微生物技术应用于各类废水处理提供参考。     

UV-254 nm活化过硫酸盐降解麻黄碱的影响因素和机理

采用UV-254 nm活化过硫酸盐高级氧化技术去除水中污染物麻黄碱(EPH),并研究了其降解动力学过程和降解机理.考察了过硫酸盐(PS)投加量、EPH的初始浓度、不同pH值及不同离子(HCO~-_3、NO~-_3、Cl~-)对降解效果的影响.结果表明,UV-254 nm活化过硫酸盐工艺能有效去除实验条件下的EPH,其氧化降解反应符合二级动力学方程.EPH去除率随着PS投加量的增加而增大.pH对降解反应有较大的影响,在pH=7的条件下,反应速率最快,表观反应动力学常数(k_(obs))为0.467 min~(-1).进一步研究表明,HCO~-_3、NO~-_3和Cl~-对EPH的降解都存在抑制作用,在相同浓度下,其抑制程度依次为Cl~- NO~-_3 HCO~-_3.通过UPLC-MS/MS鉴定了麻黄碱降解的中间体,并提出了可能的降解机理和转化途径.     

极性有机化合物整合采样技术在水环境有机污染物监测中的应用

极性有机化合物整合采样技术(Polar organic chemical integrative samplers,POCIS)适用于极性有机污染物的采集,随着新型极性有机污染物的不断出现,该技术已经引起了科学家的广泛关注.本文概述了几种常用的被动采样装置,重点介绍了POCIS采样器的一般结构、富集原理、环境因素如流速、温度、pH、溶解性有机质、盐度及膜的污染等对采样速率的影响,讨论了针对极性物质检测的质量控制和保证以及性能参考物质,综述了POCIS在水环境有机污染物监测中的应用.最后,本文对POCIS的应用前景进行了展望.     

有机污染土壤电动-微生物修复过程中的影响因素及优化措施

生物修复技术因其费用低、对环境不产生二次污染而被视为是一项具有广阔发展前景的技术。然而,一些强疏水性的有机污染物,生物可利用性很差,严重阻碍了其生物降解效率。电动与微生物联合修复技术(电动-微生物修复),在顽固性有机污染物的去除方面表现出巨大潜力。电场的施加可向土壤中分散外源物质、营养物质和微生物;或通过增强土壤中有机污染物与降解菌的传质过程,提高难降解有机物的生物可利用性;还可诱使土壤中的污染物产生电化学反应,增强污染物的去除效果。文章对有机污染土壤的电动-微生物修复过程的影响因素及优化措施进行了综述。文章认为,影响电动-微生物修复效率的因素主要有电场强度、污染物的生物可利用性、污染物结构和性质、微生物种群以及环境因素(如土壤pH值、土壤类型、营养物质、含水量等)。因此,在实施修复的过程中应根据污染场址的电化学特性选择合适的电流或电压梯度;另外,可通过施加表面活性剂、助溶剂或螯合剂,构建微生物群落,以及优化土壤环境条件,如调整土壤pH、提供营养物质、电子受体、共代谢基质等方式优化有机污染土壤电动-微生物修复的过程。深入研究有机污染土壤电动-微生物修复过程中的影响因素和优化措施,有望为电动-微生物修复技术在有机污染土壤的场地修复及过程调控中的应用提供一定的理论依据。     

改性木质素吸附剂和水热活化碳去除Cr(Ⅵ)的研究进展

工业化的迅速发展,导致水体中的重金属污染日益严重,不仅对自然环境的可持续发展提出了严峻考验,也严重威胁着人类的健康。治理铬[Cr(Ⅵ)]污染的众多方法中,吸附法因其环保、高效、可循环再生、无二次污染等优点,被认为是一种极具应用前景的方法。木质素碳和水热活化法获得的碳材料中均含有大量官能团,对去除废水中的Cr(Ⅵ)具有巨大潜力。本文综述了改性木质素基吸附剂和水热活化碳去除Cr(Ⅵ)的研究进展及存在的问题,展望了提高吸附剂吸附效率的方法和实现吸附剂工业化应用的途径。     

高级催化氧化法去除水中邻苯二甲酸酯的研究进展

普遍认为,邻苯二甲酸酯类物质（Phthalic Acid Esters,PAEs）是内分泌干扰物质（Endocrine Disrupting Chemicals,EDCs）,被广泛应用于增塑剂、化妆品中,具有致畸性,致癌性,致突变性以及拟/抗雌激素活性、拟/抗甲状腺激素活性等内分泌干扰特性。邻苯二甲酸酯类物质很容易扩散到环境中,在土壤、大气、水环境中均有检出,是环境中常见污染物,严重威胁人体健康和生态环境,已经引起国内外的广泛关注。在综述邻苯二甲酸酯类物质的物理化学性质、毒性影响、国内外天然水体、地下水和生活污水中的污染现状的基础上,讨论消除水环境中PAEs污染的强化混凝、吸附、膜处理、生物处理和高级氧化技术。高级氧化技术因其能够快速有效地去除饮用水和污水中不同种类的有机污染物而备受关注,且发展迅速。重点介绍了高级催化氧化法对水环境中PAEs的去除,包括催化湿式过氧化物氧化过程,催化臭氧氧化过程,光催化氧化过程,超声波、微波辅助催化氧化过程以及高级纳米催化氧化过程。其中,Fenton催化氧化技术在氧化过程中通过使用催化剂或协同紫外光等方式产生高度反应性羟基自由基,可无选择性地将PAEs完全降解为无毒无害的小分子物质,对PAEs的氧化去除效果最好。虽然在高级氧化过程中应用催化剂可大大提高氧化效率和降解程度,但催化氧化法耗能较大、催化剂消耗量大、受水体pH值的影响,且研究大多限于实验室阶段,未能大量投入工业应用,需要进一步发展创新。因此,开发新型高效催化剂、提高催化剂选择性、优化催化氧化反应条件、优化设计催化反应器、与其他技术耦合是水体中PAEs类环境激素污染控制技术的发展方向。     

水体和沉积物中毒害污染物的生态风险评价方法体系研究进展

人类活动导致大量毒害污染物进入水体和沉积物,从而对水生生物产生诸多不利影响.开展毒害污染物的生态风险评价,筛选高风险毒害污染物,是毒害污染物风险管控和生态系统保护的基础.对美国和欧盟等发达国家和地区毒害污染物的生态风险评价方法进行了综述.水体和沉积物中毒害污染物风险评价的基本方法首先是采用预测或测定环境浓度(PEC或M...     

Effect of pH on the sonochemical degradation of organic pollutants

An increasing number of organic compounds are manufactured, consumed, and discarded every year. Incomplete destruction of these compounds in wastewater treatment plants leads to pollution of natural waters, posing great health and ecological concerns. Ultrasound, as an emerging advanced oxidation technology, can quickly and effectively degrade organic pollutants in waters. To improve removal efficiency of organic pollutants in an ultrasonic system, operational parameters, especially pH, have been frequently evaluated and optimized. This review show that pH-induced changes in volatility, hydrophobicity and Coulombic force between the target compound and cavitation bubbles leads to higher degradation at acidic pH for most compounds. In addition, pH also changes free radical formation and reactivity in water during sonication, thereby altering degradation kinetics of target compounds. However, the influence of pH is not always consistent for various organic pollutants covering a broad range of physicochemical properties and reactivities. A systematic investigation on the pH effect is necessary to elucidate how pH alters cavitation bubble dynamics and collapse, radical yield and reactivity, distribution of target compounds in the vicinity of cavitation bubbles, water matrices transformation, and ultimately the degradation kinetics of organic pollutants. This first systematic review provides valuable insight into the pH effects on organic pollutant sonolysis, helps to improve our mechanistic understanding of the sonochemical system, and sheds light on future application of ultrasound in water engineering.     

Removal of organic pollutants by peroxicoagulation

Peroxicoagulation is an electrochemical advanced oxidation processes in which both ferrous ions and hydrogen peroxide are generated in the cell. Organic pollutants are thus removed by degradation and coagulation. The peroxicoagulation process is a combination of electro-Fenton and electrocoagulation processes. The peroxicoagulation process is very efficient for the removal of aniline and herbicides from water and for the treatment of landfill leachate and textile wastewaters. Under acidic conditions, electro-Fenton is the predominant removal means, whereas electrocoagulation is the main removal means under neutral and alkaline conditions. As a consequence, pH regulation to acidic conditions is essential for the mineralization of organic pollutants.     

Strategies to design modified activated carbon fibers for the decontamination of water and air

The rapid industrialization has induced the entry of organic and inorganic contaminants into the environment at a rate greater than environmental cleaning. As a consequence, pollutants have accumulated in environmental media, thus posing health risk for living organisms. Here, we present surface treatment strategies that modify physicochemical properties of activated carbon fibers for environmental remediation. In particular, we review metals, metal oxides and various advanced materials used for modifying activated carbon fibers. We discuss the utilization of modified activated carbon fibers for adsorption of organic pollutants and inorganic pollutants, and for the degradation of organic pollutants by photocatalysis, electrocatalysis, Fenton process and dielectric barrier discharge. We also discuss air pollutant removal, capacitive deionization, removal of inorganic ions and microbial decontamination by modified activated carbon fibers.     

Studies on the utility of plant cellulose waste for the bioadsorption of crystal violet dye

Several synthetic dyes employed in textile and food industries are discharged into aquatic environment. These visible pollutants in water damage environment, as they are carcinogenic and toxic to humans. The use of cost effective and ecofriendly plant cellulose based adsorbents have been studied in batch experiments as an alternative and effective substitution of activated carbon for the removal of toxic dyes from waste water. Adsorbents prepared from sugarcane baggase, were successfully used to remove certain textile dye such as crystal violet from an aqueous solution. The present investigation potentiate the use of sugarcane baggase, pretreated with formaldehyde (referred as Raw Baggase) and sulphuric acid (referred as Chemically Activated Baggase), for the removal of crystal violet dye from simulated waste water. Experiments were carried out at neutral pH with various parameters like dye concentration, temperature, contact time and adsorbent dosage. Efficiency of raw baggase was found better than chemically activated baggase for adsorption of crystal violet dye. The data obtained perfectly fits in the Freundlich adsorption isotherm.     

焦化废水处理试验系统出水的生物毒性变化

焦化废水是一种典型的难降解工业废水,组分复杂,生物毒性高,大多采用生物处理联合物化深度处理的工艺,以满足炼焦化学工业的污染排放标准,但其排水安全性仍然令人担忧。为研究工艺排水安全性,选择发光细菌青海弧菌Q67、稀有鮈鲫(Gobiocypris rasus)血红细胞、活性污泥微生物群落为测试生物,研究了焦化废水及各处理阶段出水的急性毒性和遗传毒性变化,进而识别影响生物毒性的水质因子。焦化废水经过序批式生物膜反应器处理后,出水急性毒性比进水下降71%,遗传毒性下降为90%以上的轻度以下损伤,显示生物强化处理对焦化废水生物毒性有良好的去除作用。生物处理出水再经过深度处理后,则表现出不同的毒性变化:活性炭吸附法对生物急性毒性的消除最佳,但遗传毒性较生物处理出水有所升高;臭氧氧化法不仅水质改善效率差,且最终出水的生物急性毒性与遗传毒性均升高;臭氧催化氧化法对水中残留有机物去除效率较高,但也造成出水急性毒性与遗传毒性的升高。各水样对青海弧菌Q67的急性毒性与有机物、氮等水质指标表现出较强相关性,而遗传毒性与水质指标之间的相关性不显著。研究结果可为评价和改进处理工艺、保障水体生态安全提供参考。     

离子化有机污染物在沉积物和水相间的平衡分配计算

本文从热力学平衡原理出发,推导出离子化有机污染物在沉积物／水相间分配系数的理论计算模型,并以苯酚,邻氯酚,２,４－二氯酚、五氯酚和苯胺的吸附实验数据为例,计算了它们在中性分子和带电荷的离子形态下的分配系数Ｋｄ和Ｋｄｉ。以及总体分配系数Ｋｄｏ研究结果表明,离子化有机污染物在沉积物和分配行为不仅与该化学物的ｐＫａ和存在形态有关。而且还取决于环境介质的ｐＨ。     

Annual production and molecular weight as an influential factor for environmental distribution of chemicals — a case study in Japan

The changes promoted by treatment of a highly polluted soil with sulphuric acid or calcium hydroxide for changing its pH value are studied by controlling physical properties (particle size, TGA and DTA curves), evolution of metal species (exchangeable, as carbonates, related to Fe‐Mn oxides, linked to organic matter and residual) and metal uptake by plant cultures. Metal contents were determined, after wet digestion with HF—HNO₃—HC1O₄ when necessary, by AAS (Ca, Mg, Cu, Pb, Mn, Fe, Zn) or emission (Na, K). The treatment of soil with successive amounts of sulphuric leads to changes in particle size, hydration properties and exothermic peak for organic matter combustion. Very small changes were, however, detected in the alkaline treatment of soil. Soil treatments do not have practical influence on speciation of some metals (Na, K, Mg, Pb, Mn, Fe), but the intensity of the acid treatment leads to both an increase in the Cu extraction and a decrease in the Ca solubilization, probably through gypsum formation. In the case of zinc a maximum solubility in the middle of the range of acid treatment was observed. The comparison among extractants shows solubilities high for two pollutants (Pb, Cu), associated mainly to Fe—Mn oxides and organic matter, and low for two macrocomponents (Fe, K). The rest of metals, basically present in soil as carbonates or oxides, have intermediate extractions. Pot cultures weights depended mainly on both the treatment of soil (poor development in the more acid sample and drainage difficulties in the rest of acid treatments) and the situation (very low weights in laboratory runs as compared with outside), but the irrigation with water or a diluted sulphuric acid solution (at pH = 4.0) did not produce significant weight changes. Tendencies to increase plant pollution were observed for smaller soil pH, acid irrigation and probably for outside cultures, due to uptake by leaves.     

Aquatic and terrestrial organic matter in the diet of stream consumers: implications for mercury bioaccumulation

The relative contribution of aquatic vs. terrestrial organic matter to the diet of consumers in fluvial environments and its effects on bioaccumulation of contaminants such as mercury (Hg) remain poorly understood. We used stable isotopes of carbon and nitrogen in a gradient approach (consumer isotope ratio vs. periphyton isotope ratio) across temperate streams that range in their pH to assess consumer reliance on aquatic (periphyton) vs. terrestrial (riparian vegetation) organic matter, and whether Hg concentrations in fish and their prey were related to these energy sources. Taxa varied in their use of the two sources, with grazing mayflies (Heptageniidae), predatory stoneflies (Perlidae), one species of water strider (Metrobates hesperius), and the fish blacknose dace (Rhinichthys atratulus) showing strong connections to aquatic sources, while Aquarius remigis water striders and brook trout (Salvelinus fontinalis) showed a weak link to in-stream production. The aquatic food source for consumers, periphyton, had higher Hg concentrations in low-pH waters, and pH was a much better predictor of Hg in predatory invertebrates that relied mainly on this food source vs. those that used terrestrial C. These findings suggest that stream biota relying mainly on dietary inputs from the riparian zone will be partially insulated from the effects of water chemistry on Hg availability. This has implications for the development of a whole-system understanding of nutrient and material cycling in streams, the choice of taxa in contaminant monitoring studies, and in understanding the fate of Hg in stream food webs.