Evaluation of the Efficiency of a Combined Adsorption–Ultrafiltration System for the Removal of Heavy Metals,Color, and Organic Matter from Textile Wastewater

In this work an ultrafiltration (UF) membrane system was investigated for the treatment of textile wastewater. UF membranes were assisted by activated sludge and minerals, which were employed as sorbents, to remove Cu(II), Pb(II), Zn(II), Ni(II), color, and organics. Significant variations were observed in metal removal efficiencies among the textile wastewater samples of different origin, even at the same pH (= 6) due to the presence of different compounds in wastewater. At the examined pH range (5.63–9.21), the dominant mechanism for copper and lead removal was the formation of insoluble metals due to precipitation and complexation of metal ions with wastewater compounds, including adsorption of metals on suspended solids and colloidal matter. The adsorption process of metals on minerals and activated sludge was the dominant process for nickel and zinc removal at low pH, while precipitation/complexation prevailed at higher pH. The examined adsorption-UF system could produce a treated effluent having low metal concentrations that could be safely discharged into municipal sewers. COD removal ranged from 76%–92% for the five textile wastewater samples. The color removal accomplished was significant (45%–70%), and depended on the type of dye.     

壳聚糖及其衍生物吸附电镀废水中重金属离子的研究进展

壳聚糖是一种来源广泛、无毒、易降解的天然高分子材料,其分子中的羟基和氨基等官能团能与重金属离子进行螯合吸附。介绍了近几年壳聚糖对电镀废水中Cu2+、Zn2+及Cd2+等离子的吸附处理,并综述了壳聚糖的几种不同形式的衍生物吸附电镀废水中重金属离子的研究进展。     

Mathematical Modelling for Removal of Mixture of Heavy Metal Ions from Waste-Water Using Micellar Enhanced Ultrafiltration (MEUF) Process

The micellar enhanced ultrafiltration (MEUF) was studied for the removal of heavy metals using a mixture of non-ionic surfactant TWEEN-80 and anionic surfactant sodium dodecyl sulphate (SDS). The gel polarization model and resistance-in-series model were used to estimate the mass transfer coefficient (3 x 10-6 m/s) and the permeate flux. The total metal ion concentration was varied from 1 mM-4 mM and the corresponding effect of the trans-membrane pressure and limiting fluxes were studied. The modified resistance-in-series model was applied to these experimental data to correlate the flux with the feed concentration and applied pressure.     

Ultrafiltration of Wastewater from Isolated Soy Protein Production: Fouling Tendencies and Mechanisms

Membrane separation processes appear to be a good alternative in wastewater treatment systems. One of the biggest limitations is the decrease in permeate flux, which is caused mostly by concentration polarization and fouling phenomena. The extent of these phenomena are dependent on the interactions between the different solution compounds, membrane-solution interactions, and the operating conditions. The fouling tendencies of three different commercial tubular ceramic membranes (5, 20, and 50 kDa) during the ultrafiltration of an isolated soy protein (ISP) wastewater were evaluated through determination of the water permeate flux before and after the wastewater ultrafiltration and using Hermia's Model. The wastewater from ISP production is a complex solution characterized by a very high organic load: reaches COD values greater than 18,000 mg · L^?1. The wastewater proteins are small molecules (8 to 50 kDa) that could not be removed during the industrial processing. The recovery of these small proteins and their return to the ISP production process would result in both economical and environmental benefits by increasing the final product yield and reducing significantly the wastewater organic load. All the membranes tested presented a large fouling tendency: 65% (5 kDa membrane), 69% (20 kDa membrane) and 76% (50 kDa membrane). The best fit to Hermia's Model for all of the UF membranes was obtained by the complete blocking model.     

Fenton氧化-沸石吸附联合处理化学镀镍废水

以Ni~(2+)、总磷和氨氮为考察对象,采用Fenton氧化和沸石吸附联合处理化学镀镍废水。探讨了Fenton破络及协同氧化非正磷酸盐时,H_2O_2的质量浓度、m(Fe~(2+))∶m(H_2O_2)、初始pH值对Ni~(2+)和总磷去除率的影响。另外,研究了沸石吸附氨氮时,沸石量、吸附时间、吸附pH值对氨氮去除率的影响。结果表明:当H_2O_2的质量浓度为6.66g/L、m(Fe~(2+))∶m(H_2O_2)为0.06、初始pH值为3时,破络完全,非正磷酸盐转化率为99.45%;同时,Ni~(2+)和总磷的去除率分别达到99.72%和91.88%。当沸石量为8g/100mL、pH值为7、反应时间为60min时,氨氮的去除率为86.30%。     

改性壳聚糖处理重金属废水研究现状

介绍了壳聚糖处理重金属废水时常用的改性方法,即化学改性(包括交联改性和接枝改性)和物理改性.综述了改性壳聚糖在重金属废水及电镀废水处理中的应用,重点介绍了交联改性壳聚糖与接枝改性壳聚糖对废水中重金属吸附的研究现状.探讨了改性壳聚糖处理重金属及电镀废水的发展方向.     

连续砂滤—超滤组合工艺的除污染效能与优化

构建了连续砂滤-超滤中试组合工艺,研究了其的除污染效能。结果表明,增加滤层厚度、降低滤速及延长洗砂周期均有助于提高连续砂滤的除污染效果。加氯反冲洗对超滤的除浊效果无影响,可以更有效地洗脱类腐殖质、类蛋白质以及微生物代谢产物等污染物,洗脱率比水力反冲洗的分别提高了57.9%、99.7%和107.3%,有效缓解了超滤的不可逆膜污染,超滤系统可以长期稳定运行,不需进行化学清洗。组合工艺的浊度去除效果极佳,出水浊度始终低于0.1 NTU;CODMn和UV254的去除率分别达34.2%和21.8%。连续砂滤有效控制了微污染原水的浊度和有机物含量,确保超滤系统可以稳定运行。研究成果可为微污染水源水的物化处理工艺提供技术支持。     

含氰含铜镍电镀废水处理技术研究

以宜昌某电镀企业产生的废水为研究对象,对其处理方法进行了探索,通过实验研究发现,用漂白粉处理含氰废水时,当漂白粉∶CN-质量比约11∶1,对CN-去除效果好;用多硫化钙法处理铜、镍电镀重金属废水效果好,上层清液不用再到中和池即可排放,且显碱性的上清液可以回用到除氰装置中,克服了传统电镀废水处理工艺的不足。     

电镀废水有机污染物去除方法研究进展

电镀废水中有机污染物来源主要有4个方面：电镀前处理、电镀处理、电镀后处理和退镀工序,讨论了有机污染物的去除方法（强化混凝法、吸附法、微电解法、Fenton氧化法、生化法和组合工艺）、处理现状,并对电镀废水中有机物处理前景进行了展望.     

Amidoximation of Cyano Group for Chelating Ion Exchange of Some Heavy Metal Ions from Wastewater

Ion exchange behavior of some heavy metal ions, Pb²⁺, Ni²⁺, and Cd²⁺, onto amidoximated polyacrylonitrile based Ce(IV) phosphate was investigated. Polyacrylonitrile based Ce(IV) phosphate was prepared and followed by functionalization of the cyano group to amidoxime group with hydroxylamine. The amidoximated resin was characterized using FT-IR and SEM. Removal of Pb²⁺, Ni²⁺, and Cd²⁺ ions from aqueous solution was examined by studying some factors using the batch technique such as effect of pH, contact time, initial metal ion concentration, and temperature. Some kinetic and isotherm models had been applied. The calculated amount of the sorbed values in case of the pseudo-second-order model are closer to the experimental data than that of the pseudo-first-order model, and with a correlation coefficients R² > 0.99. Therefore, the sorption of the three metal ions can be approximated more favorably by the pseudo-second-order model. The sorption process obeys the Freundlich isotherm model. The sorption has an endothermic nature which is indicated by the positive value of the enthalpy change, ΔH, the high positive values of the entropy change, and ΔS show the increased randomness at the solid/solution interface. The obtained negative values of free energy change, ΔG, indicate the feasibility and the spontaneous nature of the sorption process.     

超滤技术在废水回用处理中的应用

超滤具有分离效率高、工艺设备简单、操作管理方便、无相变和节约能源等特点,在废水回用处理领域具有广泛的应用。本文对超滤技术作了简要的描述并对超滤在废水处理领域的各种不同应用形式展开了分析讨论,最后介绍了超滤技术在目前的实际应用中存在的主要问题。     

超滤分离技术在污水处理中的研究与应用

综述了2000年来超滤膜分离技术在污水处理中的最新研究动态与应用情况,重点阐述了适于污水处理的超滤膜的制备和改性、超滤分离动力学过程模拟、膜组合工艺、分离操作条件的最优化设计、超滤膜污染机理以及防治技术等方面的研究近况,并对超滤技术在水污染防治中的研究与应用前景进行了展望。     

工业废水中重金属离子的常见处理方法

根据工业废水中重金属的性质,采取科学合理的方法分离重金属,提升工业废水处理水平,是水环境污染防治领域的主要课题。本文以工业废水中重金属离子种类不同、在溶液中存在形态各异为基础,重点介绍了如何利用化学法、物理化学法和生物化学法等常见方法来分离重金属,有效处理工业废水。     

活性氧化铝吸附-超滤组合工艺除氟的实验研究

试验旨在为设计一套农村小型集中式或分散式除氟供水设备提供参考。采用了活性氧化铝吸附-超滤组合除氟工艺进行地下水除氟的试验,研究了该系统原水的pH、回流量、膜通量对于除氟效果和膜污染情况的影响。结果表明,在恒流条件下,原水氟浓度2 mg/L,反冲周期6 h,反冲时间2 min,反冲强度150 mL/min,投加粒径200～300目的活性氧化铝0.2 g/L,保持原水pH=6.5左右,膜通量=45 L/m~2·h,沉淀池与反应池间的回流比=0.5,能使该系统的出水氟浓度1.2 mg/L,总铝含量0.1 mg/L,浊度0.05,并且能有效地缓解膜污染,使反应器长期运行。     

Insights into the Adsorption of Heavy Metals from Wastewater using Diatomaceous Earth

The release of large quantities of heavy metals (e.g., Zn, Cu, Pb, Ni, Cd, etc.) into the natural environment has resulted in a significant number of environmental problems, disorderliness in human physiology, and other biological systems due to their high toxicity to plant, animal, and human life. This review paper explores the feasibility of diatomaceous earth for the adsorption of heavy metals from wastewater, its application in metal adsorption, and wastewater purification. Impregnating the diatomite surface with 0.38 g/g of manganese oxide gave a 2.4-fold increase in the adsorbent surface area. A number of equilibrium studies demonstrated that treated diatomite has a higher removal capacity for heavy metals from water than untreated diatomite. The future challenges and prospect of diatomite were also addressed. Conclusively, it was established that the use of diatomaceous earth is a promising technology in the removal of heavy metals from wastewaters and environment     

聚乙烯亚胺辅助超滤法处理含锶含钴废水

研究了聚乙烯亚胺（PEI）辅助超滤处理含重金属离子锶（sr2＋）和钴（Coz＋）的废水。重点考察了PEI与重金属离子的质量浓度比（P／M）,溶液pH以及离子强度对sr^2＋和Co“截留率的影响。结果显示PEI去除sr^2＋和Co^2＋的最适pH为5和9,去除两种金属离子的最佳P／M值均为10。在最佳P／M值和最适pH时,对锶和钴的截留率分别为59％和100％。试验结果表明使用PEI辅助可以大大提高超滤膜对重金属废水中Sr^2＋和C0^2＋（尤其是con）的去除效率。     

化学沉淀法处理化学镀镍废水的研究

采用化学沉淀法从含镍废水中回收镍,通过实验确定了氢氧化钠处理废水的最佳工艺参数,回收得到镍盐,并对沉渣处理进行了初步探讨。结果表明:以双氧水为破络剂,氢氧化钠为沉淀剂,双氧水用量为50ml/L,氢氧化钠用量为25g/L,温度为60℃时沉淀效果最佳。     

电镀废水处理的研究进展

电镀废水含有大量重金属元素,如果不加处理,任意排放,势必对环境造成巨大的影响。文章概述了电镀废水的来源和组分,阐述了电镀废水的危害,对电镀废水的处理方法做了介绍,最后预测了电镀废水处理技术的发展趋势。     

腐植酸树脂处理含重金属离子废水可行性探讨

利用泥炭为原料制备腐植酸树脂。在动态条件下,研究了腐植酸树脂对重金属离子Zn2+、Ni2+的吸附效果及吸附条件并探讨了吸附与解吸再生机理:主要吸附形式为离子交换吸附和络合吸附。实验结果表明,在20℃,流速为4mL/min,pH值为5.0～7.0条件下,含Zn2+、Ni2+质量浓度均为70mg/L的废水,经腐植酸树脂处理后,Zn2+、Ni2+去除率可达98%以上,且处理后废水近中性。含Zn2+、Ni2+质量浓度分别为32.5mg/L和29.4mg/L,pH值为5.9的电镀废水,经腐植酸树脂处理后,废水中Zn2+、Ni2+含量显著低于国家排放标准允许值。     

一种处理含重金属离子电镀废水的新工艺

研究了用微电解-生物膜法复合工艺处理含重金属离子和氰离子的工业电镀废水,并与单一生物膜法处理进行了比较。结果表明,单一生物膜法对废水中的Zn2+、Cr6+和CN-的去除率分别为 50 5%、99 99%和95 8%。以不锈钢材料作阴、阳极,复合工艺相对于单一生物膜工艺对Zn2+、Cr6+和CN-的去除率均有不同程度的提高,最显著的是Zn2+的去除率由 50 5%提高到 72%;复合工艺最佳反应循环量和压缩空气用量分别为15~30mL/min和 0 3m3 /h。