含铬污泥资源化方法研究进展

电镀、印染、制革等行业在生产过程中产生大量的固体废物，因为固体废物中含有重金属铬，并且易转化为剧毒的六价铬，致使整个行业的发展都受到了制约。本文对各行业含铬污泥的产生原因、物质组成等进行了简单叙述，并介绍了之前对含铬污泥的常规处理方法，但这些方法对环境有所影响，已经不符合可持续发展的观念。含铬污泥组成复杂，有潜在的利用价值，文中对一些含铬污泥的资源化利用方法进行了介绍，指出无论是常规处理方法或是资源化利用方法，如何避免含铬污泥中的重金属铬转化为剧毒的六价铬是其中的重点。因此介绍了行业内对三价铬转化为六价铬机理进行的探究，并找到了适合的处理方法，即将重金属铬固定封装不仅抑制了三价铬转化为六价铬，还能同时进行固体废物的资源化利用。     

厌氧污泥处理含铬废物的研究

利用城市污水处理厂的厌氧污泥对含铬废物进行解毒研究,结果表明,在厌氧条件下,厌氧污泥对重铬酸钾溶液和铬渣进行解毒后,滤液中的Cr6+质量浓度极低,大大低于《污水综合排放标准》的0.5 mg/L。厌氧污泥的解毒效果与含铬物料的量、解毒时间等因素有关。     

含铬污泥处理及其资源化利用技术研究进展

对我国含铬污泥的处理与利用的现状,从含铬污泥处置、有价值资源的提取和资源化利用三方面的研究进展进行了综合的阐述。介绍了传统的含铬污泥处理方法,重点论述了近年来含铬污泥的建材利用与铬的回收利用的发展方向,分析了各种方法的利弊与可行性。并对绿色环保的铬泥处理方式和新兴的铬泥资源化利用的方法进行了展望。     

从含铬废液中制取铬绿

含铬废水的治理方法很多,如:逆流漂洗法、蒸发浓缩法、离子交换法等等,在废水的治理和回收利用资源方面许多单位已取得了显著的效果。用电解法和亚铁还原法处理后的污泥尚需另行处置,用此种方法处理的污泥,其中的铬难以回收利用。昆明市采用的化学法处理含铬废水后的氢氧化铬污泥制取三氧化二铬——铬绿,作为建筑材料用的颜料,这样既达到了治理的目的,又符合了化害为利,变废为宝     

含铬污泥中铬的氧化处理研究

考察了含铬污泥的氧化方法。采用硫酸溶液将污泥中的三价铬浸出后,在碱性条件下,以过氧化氢为氧化剂将浸出液中的三价铬氧化成六价铬。当过氧化氢计量比为3.9,反应pH值为11.0,反应温度为50℃时,三价铬氧化率可以达到96.5%。该方法用于污泥处理可实现铬铁的分离和铬的回收利用。     

铬在线监测数据超标原因及对策

针对某含铬废水处理站铬在线监测数据出现非连续性超标现象,对废水处理工艺、废水排放规律、在线监测系统工艺过程、在线监测设备失准等可能造成铬数据出现非连续性超标的因素进行了分析.研究结果表明:铬酸根还原不彻底,与加入的混凝剂中的铝离子形成铬酸铝沉淀,存在于污泥和悬浮物中;由于含铬废水处理系统中无过滤装置,导致排水悬浮物浓度...     

微波消解-火焰原子吸收法测定制革污泥中总铬

采用硝酸-盐酸-氢氟酸三元混合酸体系对制革污泥进行微波消解前处理,将各种形态的铬转化为水溶态铬,然后通过火焰原子吸收分光光度法测定污泥样品中总铬的含量。结果表明:样品加标回收率为86%～102%,相对标准偏差为14.3%,准确度和精密度较为理想。本方法适用于制革污泥以及其它含铬污泥的分析测定,为污泥处理和资源化利用提供依据。     

电镀含铬废水及其沉淀污泥中铬的回收工艺

采用NaOH和Na2CO3饱和溶液调节电镀含铬废水pH,分离废水中Cr（Ⅵ）与Cr（Ⅲ）及杂质,在氧化分离后的含铬滤渣和含铬污泥回收其中的铬。含铬废渣氧化回收铬的最佳工艺条件为反应时间90min,温度70℃,pH8．5-9．0,含铬废渣中铬的回收率达到95％;预处理和废渣氧化回收两部分的含Cr（Ⅳ）溶液合并,加入Pb（NO3）2溶液作为沉淀剂生成中铬黄颜料,铬的回收率在99．9％以上,产品符合国标GB／T3184-93的质量标准;处理后的排放水中Cr（Ⅳ）的浓度小于0．3mg／L,总Cr含量小于0．8mg／L,达到《污水综合排放标准》（GB8978—1996）的要求;处理后的废渣中的铬低于0．5％（干样）,主要为难氧化难浸出的Cr（Ⅲ）铬盐,可以安全填埋。处理工艺达到了对含铬废水和含铬污泥无害化处理和资源化利用的目的,环境效益和经济效益显著。     

电镀污泥铬回收工艺研究

本研究提出了在碱性条件下直接氧化浸出电镀污泥、净化除杂后制备中铬黄的新工艺。试验重点考察了氧化剂用量、浸出时间及反应温度对铬浸出率的影响,结果表明,控制氧化剂用量及浸出反应时间,能使铬的浸出率达到75.0%以上;含铬浸出液经净化除杂后,可以制得合格的中铬黄产品。     

废水中的铬处理及铬吸附热力学研究现状

含铬废水污染通过食物链或环境危害人们的健康,含铬废水无害化处理及污染控制至关重要。介绍了含铬废水中铬处理的萃取法、生物还原法、离子交换法、化学还原法、光催化、吸附法等的进展以及优缺点,铬吸附量测定方法近期进展。含铬废水中的铬吸附过程热力学分析对吸附处理效率的提高有帮助。利用铬吸附等温线有关文献,综述有关炭材料吸附处理铬以及铬吸附数据的热力学研究现状。     

Environmental and technical aspects of the utilisation of tannery sludge as a raw material for clay products

This paper is a report on the results of a feasibility study on the immobilisation of tannery sludge by producing a ceramic product. The main purpose of this work was to test the clays used in the manufacture of a ceramic that could incorporate tannery sludge. The raw materials, tannery sludge and clay, were mixed together in different proportions. The ceramic specimens were characterised with respect to water absorption, porosity, linear shrinkage and transverse rupture strength. Leaching tests, in accord with the Brazilian and German regulations, were done on ceramic bodies made with different additions of sludge. In order to evaluate the possibility of air contamination during the firing process, preliminary studies of air emissions were carried out The mechanical properties of the samples evaluated were similar to those specified for ceramic bricks. All the leaching tests have shown that the main sludge contaminant i.e. chromium, could be immobilised within a finished ceramic product. The studies of air emissions have shown that zinc and chlorine are mainly collected from gas emissions and hence are not immobilised by the ceramic system. The study shows that the properties of the ceramic materials produced are acceptable for applications such as bricks for the building industry.     

制革污泥的资源化利用研究进展

制革污泥的资源化利用已日益引起人们的重视,系统综述了制革污泥资源化技术的研究现状和趋势,认为制革污泥的资源化利用是制革污泥处置与利用的有效途径。     

热重-红外联用分析制革污泥的燃烧特性

利用TG-FTIR对制革污泥的燃烧特性和燃烧过程气体释放情况进行了研究。研究发现,制革污泥挥发分和灰分含量较高,固定碳含量低、热值低。不同升温速率下,制革污泥的燃烧在800℃时已经比较充分,随着升温速率的增加,制革污泥碳燃烧的失重速率和峰值温度有所增加。运用Ozawa法进行活化能计算表明,制革污泥燃烧所需活化能随着反应程度的深入而增加。制革污泥的挥发分燃烧阶段符合三维扩散的Z-L-T方程反应模型,固定碳燃烧阶段符合自催化反应的P-T方程反应模型,且制革污泥在不同升温速率下燃烧动力学参数存在动力学补偿效应。TG-FTIR分析表明,不同升温速率对气体析出基本特征没有影响,在低温阶段,制革污泥的燃烧产物中有少量的有机酸组分析出。     

污泥堆肥及其复合肥对草坪生物效应和环境效应的影响

研究了污泥堆肥及复合肥对草坪草的生物效应、土壤效应的影响.试验结果表明,污泥堆肥及草坪专用复合肥对草坪草的生长具有良好的生物效应.污泥堆肥及复合肥的施用使草坪草的叶绿素含量增加,污泥堆肥施用量高的叶绿素含量明显高于其它处理,达到了一级水平.试验结果还表明,污泥堆肥及复合肥的施用促进了草坪草叶片对氮素的吸收,使草坪草在成坪期获得了充足的养分.并保持了肥料的持续性.污泥堆肥及复合肥对草坪草具有较好的培肥效应,污泥堆肥及复合肥处理可提高土壤全量及有效N,P和K含量,且明显高于对照组.     

Solidification/stabilization of thermally‐treated toxic tannery sludge

The high concentration of trivalent chromium along with organic/inorganic compounds in tannery sludge causes severe ground‐water contamination in the case of land disposal and chronic air pollution during incineration. In the present investigation the sludge was subjected to starved‐air combustion at 800 °C, which prevented the conversion of Cr³⁺ to Cr⁶⁺. The efficiency of starved‐air combustion was confirmed through differential thermo‐gravimetric analysis (DTG), electron spin resonance (ESR) and Fourier transform infrared (FTIR) analysis. The calcined sludge was solidified/stabilized using fly ash, clay, lime and Portland cement as mixture constituents. The solidified specimens were tested for compressive strength and heavy metal fixation. The compressive strength and metal fixation of the calcined sludge (Cs)–fly ash (F)–cement (C) mortar at a ratio of 41.66% Cs, 41.66% F, 16.66% C were 185 kg cm^?2 and 93.84%, respectively. The stabilization of chromium(III) in the cement gel matrix was confirmed with scanning electron microscopy. Leachability studies were carried out to determine the percentage of metal fixation and chemical oxygen demand in the leachate. Copyright © 2006 Society of Chemical Industry     

Treatment of tannery wastewater by chemical coagulation

The objective of this study was to develop a treatment system that can effectively reduce the concentration of pollutants in tannery wastewater to environmentally acceptable levels and that can greatly reduce the cost of discharging the effluents. Aluminium sulphate and ferric chloride were used as a coagulant in the process. The influence of pH and coagulant dosages on the coagulation process was studied and conditions were optimised corresponding to the best removal of organic matters, suspended solids as well as chromium. The COD and chromium were removed mainly through coagulation: 38-46% removal of suspended solids, 30-37% removal of total COD from settled tannery wastewaters and 74-99% removal of chromium at an initial concentration of 12 mg/l can be achieved by using the optimum coagulant dosage (800 mg/l) in the optimum pH range (around 7.5). Ferric chloride produced better results than aluminium sulphate. The initial chromium concentrations and pH values of the wastewater had a great effect on chromium removal efficiency. Low chromium concentrations and high pH produced a more effective result on chromium removal than high chromium concentrations and low pH. Higher dosages did not significantly increase pollutant removal and were not economical. Coagulation combined with centrifugation improved the removal efficiency of suspended solids (70%). A high degree of clarification is attained as indicated by an excess of 85-86% colour removal. The results provide useful information for tannery wastewater treatment.     

高浓度制革废水污泥减量化实验研究

实验主要研究制革废水厌氧最佳条件、COD去除率和污泥减量,根据制革废水的特点以及实验目的要求,在不经絮凝剂处理的情况下,加入中性酶经过2～3h的处理后,在不同外界环境下进行多组厌氧处理,使废水能够迅速的处理到一定浓度,解决制革废水厌氧处理上的难题.     

Performance evaluation of saponin over other organic acid and tap water for removal of chromium in tannery sludge by electrokinetic enhancement

The performance of Saponin over different electrolyte-mediated electrokinetic (EK) process for removal of Cr(III) from tannery sludge was assessed. Saponin exhibited maximum Cr(III) removal efficiency, i.e. 67.6–80.75% as compared to other groups of processing fluids. The possible mechanistic approach for the highest removal efficiency of saponin over other electrolytes may be attributed to synchronized effect of micelle formation and subsequent complexation and sorption of chromium ions. The highest electroosmotic flow rate of saponin indicated low electroosmotic resistance during EK process, which validates the observed trend. Therefore, saponin can be considered as a promising electrolyte for EK treatment of tannery sludge.

Abbreviation: CA: Citric acid; LA: lactic acid; OA: oxalic acid; BOD: biochemical oxygen demand; COD: chemical oxygen demand; EK: electokinetic.     

含铬制革废弃物处理的研究现状和研究思路

含铬制革废弃物经过适当处理可以回收其中的能量、重金属铬和胶原蛋白,但目前不合理的处置造成了环境污染及资源浪费。本文简述了含铬制革废弃物的来源和处置现状,综合国内外最新的含铬制革废弃物处理的文献,系统总结了含铬制革废弃物处理方式的相关研究,将处置方式分为直接处理和间接处理两大类分别进行阐述,详细介绍了吸附剂、热解、焚烧这3种直接处理方式及氧化法、酸水解法、碱水解法、酶水解法这4种间接处理方式,分析了每种处置方式的原理、存在的优缺点和应用前景,简述了各种处置方式的主要作用以及优缺点对比。最后提出了含铬制革废弃物处置的研究思路,特别是开展含铬制革废弃物热解和焚烧过程中燃烧和污染物排放机理研究。