改性TiO_2/浮石光催化去除二级出水中有机物

为了实现城市污水厂二级出水的回用,将La3＋、Fe3＋共掺杂TiO2/浮石光催化用于二级出水中有机物的去除。在优化工艺条件下,该方法对TOC的去除率为49.0%,对UV254的去除率为76.5%;出水BDOC/DOC值大幅度提高,由最初的0.21提高到0.56,增加了出水的可生化性;二级出水中存在着影响光催化去除有机物的因素,其中阴离子对有机物的去除有一定的抑制作用;光催化反应在通过O3强化后对有机物的去除率得到提高,TOC的去除率达到75.0%,光催化和O3氧化对有机物的去除具有协同效应;随着光催化反应次数的增加,催化剂活性有下降趋势,使用10次后TOC去除率下降到第一次使用时的16.7%,再生能够使催化活性恢复到使用前的95%,催化剂在使用15次以内稳定性较好。     

碳纳米管溶胶的制备及其去除水中异狄氏剂的研究

采用强酸表面氧化法对碳纳米管表面进行处理,促进碳纳米管在水中的分散,制备碳纳米管溶胶,用于去除水中低浓度持久性有机污染物异狄氏剂.扫描电镜观测表明,氧化后的碳纳米管团簇被分散开,碳纳米管被打断.碳纳米管溶胶对异狄氏剂的吸附性能研究表明,制备的碳纳米管溶胶对异狄氏剂吸附去除效能优于原始碳纳米管,优化的pH值为6,此时碳纳米管溶胶对18μg/L异狄氏剂去除率达到100%;水中的腐殖质提高了吸附去除效能;碳纳米管溶胶对异狄氏剂的吸附等温线呈线性,碳纳米管溶胶的吸附性能优于原始碳纳米管吸附性能.吸附去除后,溶胶态碳纳米管以0.05 mmol/L氯化铝从水中沉淀分离.     

Physico-chemical treatments for the complete removal of non-ionic surfactants from effluents

Adsorption isotherms for a selection of non-ionic surfactants on activated carbons indicated the effectiveness of the latter in the removal of these pollutants from secondary effluents. The removal efficiencies were found to be improved when the secondary effluent was first flocculated with ferric chloride. This effectively removed some 80% of the non-ionic surfactant in the effluent. Batch adsorption experiments with powdered activated carbon removed 97% of the surfactant at low carbon dosage. A granular carbon with the best adsorption capacity was selected for continuous-flow operation in which non-ionic surfactants, COD and anionic surfactant alkyl benzene sulphonate were monitored. The breakthrough capacity for the non-ionic surfactants was in excess of 6000 bed volumes throughput of flocculated, sand-filtered effluent in a laboratory scale carbon column. Such a procedure is suggested for the complete removal of such pollutants from effluents.     

TiO2纳米管催化活性再生处理技术

采用H2O2、Fe2（SO4）3和Fenton溶液对失活的TiO2纳米管进行再生处理,重点考察了3种溶液的浓度和处理时间等对再生效果的影响,初步分析了经处理后TiO2纳米管催化活性得到再生或增强的机理。结果表明,经H2O2溶液处理后TiO2催化活性能得到有效再生,经Fe2（SO4）3,和Fenton溶液处理后其催化活性不仅得到再生,还能显著增强,这与H2O2和Fenton的强氧化作用,及进入TiO2纳米管的Fe3＋的阻止电子．空穴对再复合作用有关。     

Biosorption of heavy metals using rice milling by-products. Characterisation and application for removal of metals from aqueous effluents

The morphological characteristics as well as chemical composition of rice husks were evaluated by different techniques such as spectroscopy and thermogravimetry. The material, which is considered a by-product obtained from rice milling, was then investigated as a potential decontaminant of toxic heavy metals present in laboratory effluents. Studies using glass columns were carried out at room temperature employing 100 ml of synthetic solutions containing Cd(II) and Pb(II) at 100 mg l(-1) in order to study the effects of pH, flow rate and particle size on Cd(II) and Pb(II) adsorption. After establishing the optimised conditions, the potentiality of rice husks for removing Cd(II) and Pb(II) ions from 100 ml of laboratory effluent, presenting concentrations before treatment of 22 and 12 mg l(-1), respectively, was evaluated. The ability to take up other metals species, such as Al(III), Cu(II) and Zn(II), present in this effluent was also studied. According to the data obtained, under the optimised conditions (pH=4.0, flow rate of 8.0 ml min(-1) and < or =355 microm rice husk particle size), 30 g of husks were necessary to attain the permissible limits for effluent release, as recommend by the EPA, for those species evolved in this work (Al, Cd, Cu, Pb and Zn).     

A tubular ceramic membrane coated with TiO2-P25 for radial addition of H2O2 towards AMX removal from synthetic solutions and secondary urban wastewater

Environmental Science and Pollution Research - This work aims to integrate several hydrogen peroxide (H2O2) activation mechanisms, photolysis (UVC irradiation), chemical electron transfer (TiO2-P25...     

LED irradiated photo-Fenton for the removal of estrogenic activity and endocrine disruptors from wastewater treatment plant effluent

Environmental Science and Pollution Research - The goal of this work was to evaluate the performance of the LED irradiated photo-Fenton process on the removal of (i) estrogenic activity and (ii)...     

Utilization of TiO2 deposited on glass plates for removal of metals from aqueous wastes

Glass plates coated with TiO2 were used in a photocatalytic process to collect mercury, lead, copper and cadmium from aqueous solutions containing individual metals and mixtures. Stripping voltammetry, verified to achieve 1-10 ppb detection limits, was used to show that individual metals at concentrations of 1000 to 5200 ppb were reduced to undetectable levels in 3 to 55 min. Capillary electrophoresis (CE) with 8-hydroxyquinoline-5-sulfonic acid as complexing agent was used when appropriate, since it could quantitate all four metals under study in one run although it was less sensitive. It was demonstrated that 100 mL solutions containing 10 ppm of each of the four metals could be treated with a 10 cm2 TiO2-coated plate to leave undetectable metal concentrations in one hour. Stripping voltammetry using carbon electrodes coated with mercury films was estimated to generate daily about 1.1 L of aqueous waste containing 0.1 ppm of each metal. The results indicate the feasibility of assembling an apparatus capable of treating the waste generated by stripping voltammetry to render the latter suitable for routine on-site analyses without environmental concern. Data were also obtained to show the effectiveness in treating silver containing solutions, indicating suitability of the photocatalytic process in treating photographic processing wastes.     

Performance evaluation of waste activated carbon on atrazine removal from contaminated water

In this study, the potential of spent activated carbon from water purifier (Aqua Guard, India) for the removal of atrazine (2 chloro-4 ethylamino-6-isopropylamino-1, 3, 5 triazine) from wastewaters was evaluated. Different grades of spent activated carbon were prepared by various pretreatments. Based on kinetic and equilibrium study results, spent activated carbon with a grain size of 0.3-0.5 mm and washed with distilled water (designated as WAC) was selected for fixed column studies. Batch adsorption equilibrium data followed both Freundlich and Langmuir isotherm. Fixed bed adsorption column with spent activated carbon as adsorbent was used as a polishing unit for the removal of atrazine from the effluent of an upflow anaerobic sludge blanket (UASB) reactor treating atrazine bearing domestic wastewater. Growth of bacteria on the surface of WAC was observed during column study and bacterial activity enhanced the effectiveness of adsorbent on atrazine removal from wastewater.     

Oxidized multiwalled carbon nanotubes as adsorbent for the removal of manganese from aqueous solution

A batch adsorption process was applied to investigate the removal of manganese from aqueous solution by oxidized multiwalled carbon nanotubes (MWCNTs). In doing so, the thermodynamic, adsorption isotherm, and kinetic studies were also carried out. MWCNT with 5–10-nm outer diameter, surface area of 40–600 m²/g, and purity above 95 % was used as an adsorbent. A systematic study of the adsorption process was performed by varying pH, ionic strength, and temperature. Manganese-adsorbed MWCNT was characterized by Raman, FTIR, X-ray diffraction, XPS, SEM, and TEM. The adsorption efficiency could reach 96.82 %, suggesting that MWCNT is an excellent adsorbent for manganese removal from water. The results indicate that second-order kinetics model was well suitable to model the kinetic adsorption of manganese. Equilibrium data were well described by the typical Langmuir adsorption isotherm. Thermodynamic studies revealed that the adsorption reaction was spontaneous and endothermic process. The experimental results showed that MWCNT is an excellent manganese adsorbent. The MWCNTs removed the manganese present in the water and reduced it to a permissible level making it drinkable.     

Phosphorus removal from piggery effluents of varying quality using lime and physico-chemical treatment methods

The choice of management practices for the treatment of piggery effluent prior to its disposal to waterways or land is governed by the desire to simultaneously minimise the cost of treatment whilst minimising pollution of the environment. Laboratory experiments were conducted to compare the removal of total and total filterable phosphorus (P) (<0.45 microm) from ortho-phosphate solutions or piggery effluent by hydrated lime or lime kiln dust alone, or from recycled piggery effluent by lime and physico-chemical treatment methods. In addition, the ability of lime to remove P from recycled piggery effluent at an intensive piggery was assessed. Most P in lime treated effluent was present in the >0.45 microm fraction because of the presence of unsettled flocs of P impregnated lime. The efficiency of total P removal by hydrated lime and lime kiln dust decreased as effluent quality declined. The efficiency of removal of total filterable P by hydrated lime or lime kiln dust was not affected by effluent quality. Hydrated lime was more efficient in removing P from effluent or ortho-phosphate solutions, but lime kiln dust was more cost effective. More than 95% of total P was removed from recycled piggery effluent when physico-chemical treatment followed settling with or without lime. The physico-chemical treatment decreased total P mainly by decreasing the number of suspended particles in the effluent and by precipitating some total filterable P as iron, aluminium or calcium compounds.     

电絮凝法去除水中四环素的效能及机理

为了探讨电絮凝法去除水中四环素的效能及机理,分别研究了电极材料、电流强度、电导率和四环素初始浓度等参数对电絮凝去除四环素的影响;并通过氧化性能评估实验、UV-vis光谱分析、X射线衍射(XRD)等方法探究电絮凝去除四环素的性能。结果表明：使用铁电极(面积300 mm × 80 mm,厚2 mm),对初始浓度0.05 mmol·L-1的四环素模拟废水进行处理,在电流强度为0.3 A、电导率为1 000 μS·cm-1、电解15 min时,四环素和总有机碳(TOC)的去除率分别可达99.6%和79.8%,并且约41.9%的四环素通过氧化降解作用从水中被去除。使用铁电极电絮凝技术能够快速高效地去除四环素,具有高氧化率、低成本的特点。     

生物滴滤塔处理H_2S臭气

目前,环保政策极其关注污水处理厂的臭气排放并制定了排放标准。本实验依托3个并联的中试生物滴滤塔对污水提升泵站的H2S臭气展开研究,考察不同H2S进气负荷、停留时间、压降和填料填装方式(竹炭-陶粒分层填装、完全混合及全竹炭填装)等因素对H2S去除率的影响。对生物滴滤塔的出气浓度、滤出液p H、SO2-4离子等进行测试分析,建立传质、降解动力学模型,并分析。在停留时间为25 s连续进气条件下,考察进气负荷在0.59~5.00 g H2S/(m3·h)范围内生物滴滤塔对H2S臭气的去除表现效果。研究结果表明,各生物滴滤塔的去除率(RE)都维持在98%以上,而且出气浓度达到厂界废气排放三级标准;相较于完全混合填装方式,分层填装在去除H2S臭气时略显优势。采用Michaelis-Menten方程描述生物滴滤塔的去除表现,表观半饱和常数Ks和最大表观去除速率Vm分别为5.92 m L/m3和5.84 g H2S/(m3·h)。     

微孔TiO2负载Pt吸附强化矿化甲苯的性能

矿化效率不足是光催化技术应用于挥发性有机化合物（VOCs）净化的关键限制因素之一。为了提高VOCs的矿化效率,制备了高比表面（736 m2·g-1）微孔TiO2材料,以其为载体构建了微孔TiO2与Pt的吸附强化光催化二元结构体系。采用比表面积（BET）、透射电镜（TEM）、X射线光电子能谱（XPS）等方法考察材料结构,并以甲苯为VOCs代表研究材料的吸附-光催化特性。结果表明,Pt修饰微孔TiO2表现出特异的吸附和催化能力,甲苯平衡吸附量和矿化效率分别是P25的3.8~4.1倍和2.6~2.9倍。微孔TiO2载体除了吸附强化作用外,其表面通过Pt修饰可产生大量表面羟基,从而利于Pt-TiO2的常温催化过程。     

CuCoOx／TiO2催化氧化NO性能研究

采用浸渍法制备了CuCoOx／TiO2催化剂,考察了焙烧温度、反应温度、氧含量、NO浓度和空间速度对催化剂催化氧化NO性能的影响,并考察了催化剂的抗硫抗水性能。XRD、TPR和BET分析表明,350℃焙烧的催化剂具有CuCo2O4尖晶石结构,比表面积大,对NO的氧化效果好。在空速为5000h^-1,NO进口浓度500mg／m^3,含氧量10％的条件下,反应温度300℃时NO转化率可达79．5％,250℃时NO转化率接近50％。该催化剂具有良好的单独抗SO2、抗H2O毒化性能,H2O和SO2同时存在时很快失活。该催化剂可用于不同时含H2O和SO2的含NO气体催化氧化后再吸收处理。     

The efficiency of the multi-walled carbon nanotubes used for antibiotics removal from wastewaters generated by animal farms

Environmental Science and Pollution Research - In the recent years, residual antibiotics are considered to be emerging environmental pollutants due to their continuous input and persistence into...     

微孔-P25复合二氧化钛矿化挥发性有机物的性能

矿化效率不足是光催化净化VOCs技术应用的主要瓶颈之一。为提升矿化效率,以十二胺为模板剂,在P25表面构建微孔二氧化钛同质吸附层。利用表面光电压谱、氮气等温吸附-脱附、X射线衍射等研究其结构特性和对甲苯的光催化降解,并探讨微孔TiO2和P25复合比例对催化剂性能的影响。结果发现,随着微孔复合比例增加,比表面积和甲苯平衡吸附量均显著提高。微孔复合比例小导致吸附对甲苯矿化的强化作用不明显,而微孔复合比例过高则造成材料光生载流子分离效率下降。微孔TiO2和P25复合比例为8∶5时,催化剂对甲苯的矿化效率最高,分别是P25和微孔TiO2的3.14和1.85倍。     

二氧化钛颗粒制备及其对水中三价砷的去除

以硫酸氧钛和聚乙烯醇(PVA)为原料,通过冰水浴法制备了二氧化钛(TiO2)颗粒,并研究了其对砷的吸附性能。利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对TiO2颗粒进行了表征,结果表明,吸附剂为锐钛矿结构,比表面积246 m2/g。TiO2颗粒对模拟地下水中砷(Ⅲ)的吸附动力学研究表明,吸附过程符合准二级动力学。采用Langmuir和Freundlich方程对吸附平衡数据进行了拟合,结果表明,吸附等温线符合Langmuir模型,最大吸附量为22.3 mg/g。TiO2颗粒对三价砷的吸附在pH为9.1时吸附量最大,吸附受CO23-影响较大。将110 g TiO2颗粒装备成过滤滤壶,对山西地下水(总砷含量190μg/L)进行了除砷实验,经过3 600柱体积后,滤液中砷浓度低于10μg/L,符合国家饮用水标准。     

Performance evaluation of intermediate cover soil barrier for removal of heavy metals in landfill leachate

This pilot-scale study evaluated the use of intermediate cover soil barriers for removing heavy metals in leachate generated from test cells for co-disposed fly ash from municipal solid waste incinerators, ash melting plants, and shredder residue. Cover soil barriers were mixtures of Andisol (volcanic ash soil), waste iron powder, (grinder dust waste from iron foundries), and slag fragments. The cover soil barriers were installed in the test cells' bottom layer. Sorption/desorption is an important process in cover soil bottom barrier for removal of heavy metals in landfill leachate. Salt concentrations such as those of Na, K, and Ca in leachate were extremely high (often greater than 30 gL(-1)) because of high salt content in fly ash from ash melting plants. Concentrations of all heavy metals (nickel, manganese, copper, zinc, lead, and cadmium) in test cell leachates with a cover soil barrier were lower than those of the test cell without a cover soil barrier and were mostly below the discharge limit, probably because of dilution caused by the amount of leachate and heavy metal removal by the cover soil barrier. The cover soil barriers' heavy metal removal efficiency was calculated. About 50% of copper, nickel, and manganese were removed. About 20% of the zinc and boron were removed, but lead and cadmium were removed only slightly. Based on results of calculation of the Langelier saturation index and analyses of core samples, the reactivity of the cover soil barrier apparently decreases because of calcium carbonate precipitation on the cover soil barriers' surfaces.     

铁盐和铝盐混凝对印染废水生化出水中溶解性有机污染物的去除特性

以三氯化铁和硫酸铝为混凝剂,印染废水二级生化出水为研究对象,并利用XAD-8/XAD-4吸附树脂联用技术将印染废水生化出水中溶解性有机物分为疏水酸、非酸疏水物质、弱疏水物质及亲水物质4类有机物,通过小试实验探讨了2种混凝剂对生化出水中各类溶解性有机物的去除效果及特点。实验结果表明,对于该印染废水的生化出水,溶解性有机物的主要成分是疏水性物质,以DOC表征时占总DOC的75%,其中疏水酸约占41%,疏水性物质也是引起色度的主要物质,所占比例以ADMI7.6表征时为89%,其中以非酸疏水物质的贡献最大,达到52%,并且非酸疏水物质中不饱和双键或芳香环有机物的含量较高。在三氯化铁和硫酸铝各自最佳的混凝条件下,均能够有效去除由疏水性物质（疏水酸和非酸疏水物质）引起的色度,但三氯化铁对弱疏水性物质以及亲水物质的去除率高于硫酸铝,这使得三氯化铁对印染废水生化出水中的溶解性有机物的去除效果优于硫酸铝。并且三氯化铁和硫酸铝混凝工艺均能明显降低生化出水的毒性。