Application of 'waste' wood-shaving bottom ash for adsorption of azo reactive dye

The utilization of wood-shaving bottom ash (WBA) for the removal of Red Reactive 141 (RR141), an azo reactive dye, was investigated. WBA/H(2)O and WBA/H(2)SO(4) were made by treating WBA with water and 0.1M H(2)SO(4), respectively, to increase adsorption capacity. Adsorption of RR141 from reactive dye solution (RDS) and reactive dye wastewater (RDW) by WBA/H(2)O and WBA/H(2)SO(4) involved the BET surface area and pore size diameter. Properties of adsorbents, effect of contact time, initial pH of solution, dissolved metals and elution studies indicated that the decolorisation mechanism involved both chemical adsorption and precipitation with calcium ions. In addition, the WBA/H(2)SO(4) surface might contain sulphate-cation complexes that were specific to enhancing dye adsorption from RDW. The adsorption isotherm had a best fit by the Freundlich model. Freundlich parameters showed that WBA/H(2)O used more heterogeneous surface than WBA/H(2)SO(4) and activated carbon for RDW adsorption. A thermodynamic study indicated that RDW adsorption was an endothermic process. The maximum dye adsorption capacities of WBA/H(2)O, WBA/H(2)SO(4) and activated carbon obtained from a Langmuir model at 30 degrees C were 24.3, 29.9, and 41.5mgl(-1), respectively. In addition, WBA/H(2)O and WBA/H(2)SO(4) could reduce colour and high chemical oxygen demand (COD) of real textile wastewater. According to the difficulty in the elution study, it was an environmentally safe disposal of this waste. Therefore, WBA, a waste from combustion of wood shavings, was suitable to be used as an effective adsorbent for azo reactive dye removal.     

Use of an activated carbon from antibiotic waste for the removal of Hg(II) from aqueous solution

Porous carbon has been prepared from waste antibiotic material by a chemical activation method using K(2)CO(3) as an activating reagent. Carbon was studied systematically by the adsorption of nitrogen and iodine. It was found that the process parameters such as activation temperature and activation time are crucial for preparing high-quality activated carbon. The proper choice of the preparation conditions allows to produce microporous activated carbon with a micropore volume up to 0.492 cm(3)/g and a BET surface area of 1260 m(2)/g. Adsorption of mercury(II) from an aqueous solution on antibiotic carbon was investigated under the varying conditions of agitation time, metal ion concentration and pH. The adsorption capacity of the carbon is 129 mg/g.     

利用粉煤灰处理采油废水的研究

利用电厂粉煤灰及灰场氧化塘对现河首站采油废水中的污染物进行吸附和生化处理试验。试验结果表明:粉煤灰具有类似活性炭的结构和比表面积,对废水中的石油类、COD、氨氮、挥发酚等污染物具有较强的吸附、沉降和过滤作用。     

炼油污水的处理

采用接触氧化—曝气生物滤池—加氯氧化—砂滤—活性炭吸附的工艺对某炼油厂污水进行处理,运行结果显示:出水中石油类和SS均小于5mg/L,达到了设计回用指标;而对COD和氨氮的降解则存在不稳定现象,针对此问题作了进一步的工艺整改后此工艺最终出水可以达到该厂制定的回用水质标准。     

粉末活性炭处理焦化废水酚的研究

通过试验研究比较粉末活性炭和柱状活性炭对焦化废水中酚的去除效率,并重点研究了粉末活性炭粒度和投加量等因素对焦化废水酚的去除效率的影响。研究结果表明：与柱状活性炭相比,粉末活性炭对焦化废水酚的去除率有明显提高;同时,粉末活性炭对焦化废水中酚的去除率受粒度大小、曝气与否,以及投加量等因素的影响。并找出最佳粉末活性炭粒度、投加量和吸附处理时间。     

氧化-吸附法联合处理油田酸化废水

实验采用双氧水氧化与活性炭吸附联合作用的方法处理酸化废水,并确定最佳工艺条件。结果表明,该法能有效降低酸化废水中污染物含量,CODＣr去除率可达82.8％。与先用双氧水氧化,然后用活性炭吸附分步法处理比较,该法操作简单,节省费用,而且可提高处理效果。     

RD吸附氧化法处理富营养化水源水的中试研究

采用RD吸附氧化法处理富营养化水源水的中试研究表明，该法可有效去除原水中的氨氮及COD，去除率可分别达到并保持在99％和75％，且运行费用远低于活性炭吸附法，是一种经济、有效的处理富营养化水源水的方法。     

Adsorption of eosin dye on activated carbon and its surfactant based desorption

The performance of activated carbon has been investigated for the adsorption of eosin dye dissolved in water. Eosin is anionic in nature and highly toxic. The effects of initial dye concentration, contact time, pH and temperature on adsorption of eosin by a fixed amount of activated carbon (1.0 g/L) have been studied in batch and column mode. The equilibrium data are successfully fitted to the Freundlich adsorption isotherm. The adsorption rate data are successfully explained by a pseudo second-order kinetic model. Breakthrough curves for column adsorption have also been studied. The regeneration of spent carbon by desorbing the dye has been experimentally investigated applying a surfactant enhanced carbon regeneration (SECR) technique using both cationic and anionic surfactants. An empirical kinetic model for dye desorption from the commercial activated carbon (CAC) using different surfactant and desorption techniques, viz. change in pH, has been proposed. The comparison between the model and the experimental results is found to be satisfactory.     

臭氧-活性炭工艺在炼化循环排污水处理中的应用＊

针对炼化企业循环排污水中有机污染物浓度不能满足脱盐处理工艺进水水质要求的问题,开展了臭氧氧化-活性炭吸附工艺去除循环排污水中有机污染物的研究。通过对两种处理工艺进行不同组合的实验结果得知:当反应时间控制在最佳值,臭氧氧化和活性炭吸附单独处理循环排污水时,COD去除率分别约为27%和20%,处理效率偏低;当两种工艺组合后,在臭氧浓度为12 mg/L、氧化时间20 min、吸附时间为10 min时,COD去除率则达到52%,组合工艺协同作用效果明显。     

活性炭的吸附机理及其在水处理方面的应用

本文从活性炭表面的物理性质和化学性质,介绍了活性炭吸附的一般机理。综述了活性炭在城市给水、工业废水及城市污水深度处理中的研究进展;混凝—活性炭吸附工艺在净水工程中的应用;臭氧—生物活性炭技术去除水中有机污染物的工艺;MBR/PAC组合工艺及工业上使用石灰石与活性炭联合去除污染物的技术;从活性炭吸附性能指标的选择、有机物分子量的分布、活性炭的改性等方面,提出了活性炭在水处理应用上的问题和展望。     

Removal of the hazardous dye rhodamine B through photocatalytic and adsorption treatments

This paper reports on photocatalytic and adsorptive treatment of a hazardous xanthene dye, Rohdamine B, in wastewater. The photocatalytic degradation was carried out in the presence of the catalyst TiO(2) and the effects of pH, concentration of the dye, amount of TiO(2), temperature and electron acceptor H(2)O(2) on the degradation process were observed. It was found that photocatalytic degradation by TiO(2) is an effective, economical and faster mode of removing Rohdamine B from aqueous solutions. Attempts were also made to utilize activated carbon and rice husk as potential adsorbents to remove Rhodamine B from wastewater. The adsorption studies were carried out at 40, 50 and 60 degrees C, and the effects of pH, temperature, amount of adsorbents, concentration of adsorbate, etc., on the adsorption were measured. On the basis of adsorption data the Langmuir and Freundlich adsorption isotherm models were also confirmed. The adsorption isotherm constants thus obtained were employed to calculate thermodynamic parameters like Gibb's free energy, change in enthalpy and entropy. In order to observe the quality of wastewater COD measurements were also carried out before and after the treatments. A significant decrease in the COD values was observed, which clearly indicates that both photocatalytic and adsorption methods offer good potential to remove Rhodamine B from industrial effluents.     

Conversion of leather wastes to useful products

The main objective of the present study is to investigate the production of useful materials from different kinds of leather waste. Three different types of tannery wastes (chromium- and vegetable-tanned shavings, and buffing dust) were pyrolyzed in a fixed bed reactor at temperatures of 450 and 600 °C under N₂ atmosphere. Gas, oil, ammonium carbonate and carboneous residue were obtained by pyrolysis. The effect of temperature and type of leather waste on product distribution of pyrolysis was investigated. Buffing dust gave the highest yield of oil (ca. 23%), while other wastes recorded yields of ca. 9%. Results of elemental analysis and column chromatography showed that pyrolysis oils could be used as fuel or chemical feedstock after re-treatment. The yields of carboneous residue (chars) were between 37.5% and 48.5% and their calorific value was between 4300 and 6000 kcal kg⁻¹, suitable for use as solid fuel. In addition, these chars were activated by CO₂ to obtain the activated carbon. The activated carbon having highest surface area (799.5 m² g⁻¹) was obtained from chromium-tanned shavings. Activated carbons prepared from chromium-tanned leather were presented as an adsorbant for the adsorption of dyes from aqueous solution.     

生物活性炭技术在水处理中的研究进展与应用

总结了生物活性炭（BAC）技术在净水处理、废水处理和污水再生利用处理中的应用;阐述了生物活性炭对污染物的去除机理;介绍了生物活性炭技术在水处理中（包括给水深度处理、多种工业废水及生活污水处理）的最新应用研究成果及该技术的发展方向。     

制药废水生化处理后的深度处理方法比较研究

随着制药废水排放标准的提高,对制药废水进行深度处理是实现其达标排放的有效途径之一。试验比较了絮凝、高级氧化、吸附、超滤等方法对生化处理后的高浓度制药废水深度处理效果,结果表明:4种方法中,只有活性炭吸附对废水COD、浊度、色度、氨氮等都具有较好的去除效果,COD去除率最高能达到62%,可实现达标排放。     

Determination of model parameters for zinc (II) ion biosorption onto powdered waste sludge (PWS) in a fed-batch system

Biosorption of zinc (II) ions onto pre-treated powdered waste sludge (PWS) was investigated using a completely mixed tank operating in fed-batch mode instead of an adsorption column. Experiments with variable feed flow rate (0.05-0.5 L h(-1)), feed Zn(II) ion concentrations (37.5-275 mg L(-1)) and amount of adsorbent (1-6 g PWS) were performed using fed-batch operation at pH 5 and room temperature (20-25 degrees C). Break-through curves describing variations of aqueous (effluent) zinc ion concentrations with time were determined for different operating conditions. Percent zinc removal from the aqueous phase decreased, but the biosorbed (solid phase) zinc ion concentration increased with increasing feed flow rate and zinc concentration. A modified Bohart-Adams equation was used to determine the biosorption capacity of PWS (q'(s)) and the rate constant (K) for zinc ion biosorption. Biosorption capacity (q'(s)=57.7 g Zn kg(-1) PWS) of PWS in fed-batch operation was found to be comparable with powdered activated carbon (PAC) in column operations. However, the adsorption rate constant (K=9.17 m(3) kg(-1) h(-1)) in fed-batch operation was an order of magnitude larger than those obtained in adsorption columns because of elimination of mass transfer limitations encountered in the column operations. Therefore, a completely mixed tank operated in fed-batch mode was proven to be more advantageous as compared to adsorption columns due to better contact between the phases yielding faster adsorption rates.     

含多聚甲醛类化合物高浓度COD废水处理方法研究

目标废水来自郴州某制药厂,具有COD高、可生化处理能力差的特点。本实验针对废水特点,提出了Fenton氧化、次氯酸钠氧化等高级氧化为主,活性炭吸附为辅的处理方案,同时探讨了加热回流时间、pH、Fe2＋投加量、H2O2投加量、次氯酸钠投加量分别对COD降解率的影响,得出最佳处理条件。     

酸催化氧化法处理含对苯二酚废水的方法

本文主要研究用硫酸作催化剂，30％过氧化氢作氧化剂，再经过pH值的调节和活性炭吸附，使对苯二酚化学需氧量值从3615mg／L降至260mg/L。化学需氧量的去除率高达93．3％。     

Optimization of Fenton's oxidation of chemical laboratory wastewaters using the response surface methodology

Establishing a treatment process for practical and economic disposal of laboratory wastewaters has become an urgent environmental concern of the Department of Chemical Engineering of the Universidade Estadual de Maringá (State University of Maringá), Brazil. Fenton and related reactions are potentially useful oxidation processes for destroying toxic organic compounds in water. In these reactions, hydrogen peroxide is combined with ferrous or ferric iron in the presence or absence of light to generate hydroxyl radicals (.OH). The feasibility of Fenton's reagent to treat waste chemicals from an academic research laboratory was investigated in this study. A response surface methodology was applied to optimize the Fenton oxidation process conditions using chemical oxygen demand (COD) removal as the target parameter to optimize, and the reagent concentrations, as related to the initial concentration of organic matter in the effluent, and pH as the control factors to be optimized. Maximal COD removal (92.3%) was achieved when wastewater samples were treated at pH 4 in the presence of hydrogen peroxide and iron in the ratios [COD]:[H2O2]=1:9 and [H2O2]:[Fe2+]=4.5:1. Under these conditions, it was possible to obtain simultaneously maximal COD removal and minimal chemical sludge after treatment, which is a residue that needs further processing.     

Removal of mercury from aqueous solutions using activated carbon prepared from agricultural by-product/waste

Removal of mercury from aqueous solutions using activated carbon prepared from Ceiba pentandra hulls, Phaseolus aureus hulls and Cicer arietinum waste was investigated. The influence of various parameters such as effect of pH, contact time, initial metal ion concentration and adsorbent dose for the removal of mercury was studied using a batch process. The experiments demonstrated that the adsorption process corresponds to the pseudo-second-order-kinetic models and the equilibrium adsorption data fit the Freundlich isotherm model well. The prepared adsorbents ACCPH, ACPAH and ACCAW had removal capacities of 25.88 mg/g, 23.66 mg/g and 22.88 mg/g, respectively, at an initial Hg(II) concentration of 40 mg/L. The order of Hg(II) removal capacities of these three adsorbents was ACCPH > ACPAH > ACCAW. The adsorption behavior of the activated carbon is explained on the basis of its chemical nature. The feasibility of regeneration of spent activated carbon adsorbents for recovery of Hg(II) and reuse of the adsorbent was determined using HCl solution.     

Waste materials for activated carbon preparation and its use in aqueous-phase treatment: a review

Commercial activated carbon is a preferred adsorbent for the removal of micropollutants from the aqueous phase; however, its widespread use is restricted due to high associated costs. To decrease treatment costs, attempts have been made to find inexpensive alternative activated carbon (AC) precursors, such as waste materials. Some reviews report the use of waste materials for the preparation of AC; however, these studies are restricted to either type of wastes, preparation procedures, or specific aqueous-phase applications. The present work reviews and evaluates literature dedicated both to the preparation of AC by recycling different types of waste materials and also to its application in various aqueous-phase treatments. It is clear that conventional (from agriculture and wood industry) and non-conventional (from municipal and industrial activities) wastes can be used to prepare AC, that can be applied in various aqueous treatment processes, namely to remove organic pollutants, dyes, volatile organic compounds, and heavy metals. Moreover, high surface areas can be obtained using either physical or chemical activation; however, combined treatments might enhance the surface properties of the adsorbent, therefore increasing its adsorption capacity. It is evident from the revision made that AC prepared from both conventional and non-conventional wastes might effectively compete with the commercial ones. This happens mostly when the activation procedures are optimized considering both the raw material used to produce the carbons and the contaminants to be removed.