EXPERIMENTAL INVESTIGATION ON ADSORPTION OF AMIDO BLACK 10B DYE ONTO ZEOLITE SYNTHESIZED FROM FLY ASH

This work presents experimental studies on adsorptive removal of Amido black 10B dye using a low-cost zeolite synthesized from fly ash to study the effect of various parameters, namely pH, temperature, agitation speed, adsorption time, zeolite loading, and dye concentration, on dye removal efficiency. Dye removal efficiency increased with increase in adsorbent dosage, adsorption time, and stirrer speed, and the optimal values of zeolite dose, adsorption time, and stirrer speed were found to be 10 g/L, 6 h, and 300 rpm respectively. On the other hand, dye removal efficiency decreased with increase in the initial dye concentration as well as temperature, indicating that the adsorption process is exothermic and is effective at low concentrations of adsorbate. Maximum dye removal was obtained at low pH values (between 2 and 5), indicating the fact that the zeolite surface is positively charged. Experimental data matched well with the pseudo-first-order kinetic model and the Freundlich equilibrium isotherm. The most important observation in this work is that zeolite synthesized from fly ash could act as a very effective adsorbent for the removal of amido black dye from its aqueous solutions.     

PRODUCTION OF LOW-COST CARBON ADSORBENTS FROM AGRICULTURAL WASTES AND THEIR IMPACT ON DYE ADSORPTION

This study concerns utilizing commonly available agricultural wastes like mustard stalk, jute stalk, sesame stalk, wheat straw, bagasse, and rice husk in a proper and efficient way. As a part of this research, activated carbon has been prepared from these wastes by a two-stage activation process with a carbonization stage up to 325°C as a first stage followed by chemical activation using zinc chloride as an activation agent. The effects of temperature, time, and impregnation ratio on activation have been studied. The batch adsorption technique has been utilized to obtain information for treating effluents from the dye industry. Methylene blue dye has been chosen as the standard. Adsorption data have been modeled using the Freundlich and Langmuir adsorption isotherms and first- and second-order kinetic equations and intraparticle diffusion model. Specific surface area was determined by the methylene blue spot test. The results indicate that such carbons can be employed as low-cost alternatives to expensive commercial activated carbon in wastewater treatment to remove water-soluble dyes.     

PRODUCTION OF LOW-COST CARBON ADSORBENTS FROM AGRICULTURAL WASTES AND THEIR IMPACT ON DYE ADSORPTION

This study concerns utilizing commonly available agricultural wastes like mustard stalk, jute stalk, sesame stalk, wheat straw, bagasse, and rice husk in a proper and efficient way. As a part of this research, activated carbon has been prepared from these wastes by a two-stage activation process with a carbonization stage up to 325°C as a first stage followed by chemical activation using zinc chloride as an activation agent. The effects of temperature, time, and impregnation ratio on activation have been studied. The batch adsorption technique has been utilized to obtain information for treating effluents from the dye industry. Methylene blue dye has been chosen as the standard. Adsorption data have been modeled using the Freundlich and Langmuir adsorption isotherms and first- and second-order kinetic equations and intraparticle diffusion model. Specific surface area was determined by the methylene blue spot test. The results indicate that such carbons can be employed as low-cost alternatives to expensive commercial activated carbon in wastewater treatment to remove water-soluble dyes.     

零价铁/MCM-48介孔分子筛协同处理染料废水的研究

以活性艳兰染料废水为目标降解物,研究废铁屑投加量、MCM-48介孔分子筛投加量、和反应接触时间等影响因素。结果表明:在最优条件铁屑投加量100 g/L、介孔分子筛投加量1g/L、振荡时间30min下,废水脱色率可达到85%,COD去除率也可达到65%。该降解反应动力学方程基本符合准一级动力学反应。     

羟基铁交联累托石吸附重金属离子Cr6+的研究

研究羟基铁交联累托石的制备及其对Cr6+的吸附性能.当溶液pH值为3左右,羟基铁交联累托石(以下简称CLR)～的用量为13.2g/LH20时,常温振荡吸附60min,Cr6+的去除率可达到98%,残留Cr6+浓度可降至0.5mg/L以下.     

ADSORPTION OF AUTOMOTIVE PAINT SOLVENTS ON ACTIVATED CARBON: III. EQUILIBRIUM ADSORPTION OF BINARY MIXTURES

The use of activated carbon adsorption systems to remove volatile organic compounds released during automobile paint spray operations has received considerable attention in the past few years. In this paper, adsorption equilibria of eight automotive paint solvent pairs on activated carbon are presented. The data were obtained at total vapor concentrations of 365 ppm by volume, typical of those found in automobile assembly plant spraybooth exhaust air. Correlations of the data using two different modifications of the Polanyi adsorption potential theory in order to accommodate multicomponent equilibria are also presented and discussed. The correlations evaluated predict equilibrium compositions reasonably well for some binary mixtures. However, neither of the methods evaluated appeared to be satisfactory to correlate the equilibrium composition of all of the vapor pairs studied. A possible explanation for this behavior is that very small errors in the data available for the adsorption of pure components result in substantial changes in the predicted binary mixture compositions.     

溶液中菁染料的状态对其在AgBr表面吸附效应的量热研究

用半导体精密量热计测得25±0.01℃时溴化银从DMF-H_2O溶液中吸附噻碳菁染料(Ⅰ)的吸附热。发现由于溶液中染料聚集状态的不同导致吸附热明显不同,但吸附于溴化银表面的染料的聚集态则基本相     

CORROSION INHIBITION AND ADSORPTION BEHAVIOR OF MALACHITE GREEN DYE ON ALUMINUM CORROSION

Malachite green dye (MG) was studied as a corrosion inhibitor for aluminum in 1.0 mol dm^?3 HCl and 0.5 mol dm^?3 KOH using the gravimetric technique. The results revealed an inhibiting effect of MG, which was highly restrained in 0.5 M KOH and pronounced in 1.0 M HCl. MG inhibited the corrosion reaction in the acidic medium by adsorption on the metal/solution interface following the Flory-Huggins isotherm. Inhibition efficiency increased with MG concentration and synergistically increased in the presence of iodide ions, but decreased with a rise in temperature. The local reactivity of the MG molecule was analyzed theoretically using the density functional theory to explain the adsorption characteristics, while molecular dynamics simulations were performed to illustrate the adsorption structure of MG at a molecular level. The theoretical predictions showed good agreement with experimental results.     

多级介孔炭对刚果红染料吸附性能的研究

以商业硅胶为模板,采用硬模板法制备了多级介孔炭,并研究了其对水溶液中刚果红染料的吸附性能.研究结果表明制备的多级介孔炭具有高比表面,大孔容和集中孔径分布以及高效吸附脱除刚果红染料的性能.多级介孔炭对水溶液中刚果红的吸附等温线符合Langmuir吸附模型,且在45℃具有最大吸附量,为446.89mg·g-1.吸附动力学研究表明动力学数据遵循拟二级动力学模型.热力学研究发现,在25～45℃内,刚果红在多级介孔炭上的吸附行为时吸热过程,且是自发进行的.     

印染废水混凝脱色与染料结构及混凝剂种类间的关系

在四种无机混凝剂对六大类十二种典型染料混凝脱色实验的基础上,分析了染料分子结构与混凝剂种类对印染废水混凝脱色效果的影响的一般规律,并探讨部分混凝脱色机理。     

沸石吸附去除污水中磷的研究

研究了沸石对水溶液中磷素的等温吸附特征,考察了初始溶液浓度、沸石粒径和温度三种因素对吸附作用的影响,分析了不同条件下沸石磷素吸附动力学过程。结果表明：Langmuir方程能很好地描述沸石对磷素的等温吸附特征,其磷素最大饱和吸附量为101mg／kg。初始溶液浓度越高,沸石对磷素的吸附量越大,吸附平衡时间越长。随着沸石粒径的减小,对磷素的吸附量增大,吸附平衡时间缩短。升高温度,沸石对磷素的吸附量增大,吸附平衡时间增长。沸石对水溶液中磷素的吸附动力学过程符合准二级动力学模型,由该模型可以估算出沸石磷素平衡吸附量,误差小于5％。     

THE INFLUENCE OF PROCESS PARAMETERS ON STRUVITE CONTINUOUS CRYSTALLIZATION KINETICS

Experimental data concerning the kinetics of mass crystallization of struvite during the process of magnesium ion removal from water with the use of ammonium dihydrogenphosphate, NH₄H₂PO₄, addition under alkaline conditions are presented. The tests were carried out in a continuous laboratory DTM MSMPR crystallizer with internal circulation of suspension (T = 298 K). The influence of concentration of Mg^2 +  ions in the raw material, pH of the process environment, and residence time of suspension on the nucleation and growth rates of struvite crystals was established. Kinetic parameters were evaluated from the crystal size distributions using selected size-dependent growth (SDG) models.     

吸附法处理含氟水

以活性氧化铝为吸附剂,测定了ＮａＦ溶液的平衡吸附量和透过曲线。考察了停留时间、吸附质浓度对透过曲线的影响,获得了较佳的吸附过程操作条件,为工业设计放大提供了必要的基础数据。     

中孔炭材料的制备及吸附性能的研究

以正硅酸乙酯为模板硅源，酚醛树脂为炭前驱体，运用模板法制备了中孔炭材料。并用红外光谱（FT—IR）、扫描电镜（SEM）、低温N2自动吸附、甲醛和VB12饱和吸附等对样品形貌、孔结构和吸附性能进行了研究。结果表明：制备的炭材料孔径集中分布在2-7nm左右，且中孔孔隙率达到74．6％，比表面积达到1012m^2／g；材料对VB12大分子有较好的吸附性能。表明通过控制正硅酸乙酯的水解条件能制备孔径集中的中孔炭材料。     

STUDIES ON THE ADSORPTION OF FURFURAL FROM AQUEOUS SOLUTION ONTO LOW-COST BAGASSE FLY ASH

The present study deals with the sorptive removal of furfural from aqueous solution by carbon-rich bagasse fly ash (BFA). Batch studies were performed to evaluate the influence of various experimental parameters, namely, initial pH (pH₀), adsorbent dose, contact time, initial concentration, and temperature on the removal of furfural. Optimum conditions for furfural removal were found to be pH₀ ≈ 5.5, adsorbent dose ≈4 g/L of solution, and equilibrium time ≈4 h. The adsorption followed pseudo-second-order kinetics. The effective diffusion coefficient of furfural is of the order of 10^-13 m²/s. Equilibrium adsorption data on BFA was analyzed by Freundlich, Langmuir, Dubnin-Radushkevich, Redlich-Peterson, and Temkin isotherm equations using regression and error analysis. The Redlich-Peterson isotherm was found to best represent the data for furfural adsorption onto BFA. Adsorption of furfural on BFA is favorably influenced by a decrease in the temperature of the operation. Values of the change in entropy (ΔS⁰) and heat of adsorption (ΔH⁰) for furfural adsorption on BFA were negative. The high negative value of change in Gibbs free energy (ΔG⁰) indicates the feasible and spontaneous adsorption of furfural on BFA.     

STUDIES ON THE ADSORPTION OF FURFURAL FROM AQUEOUS SOLUTION ONTO LOW-COST BAGASSE FLY ASH

The present study deals with the sorptive removal of furfural from aqueous solution by carbon-rich bagasse fly ash (BFA). Batch studies were performed to evaluate the influence of various experimental parameters, namely, initial pH (p H ₀), adsorbent dose, contact time, initial concentration, and temperature on the removal of furfural. Optimum conditions for furfural removal were found to be p H ₀ ≈ 5.5, adsorbent dose ≈4 g/L of solution, and equilibrium time ≈4 h. The adsorption followed pseudo-second-order kinetics. The effective diffusion coefficient of furfural is of the order of 10^?13 m²/s. Equilibrium adsorption data on BFA was analyzed by Freundlich, Langmuir, Dubnin-Radushkevich, Redlich-Peterson, and Temkin isotherm equations using regression and error analysis. The Redlich-Peterson isotherm was found to best represent the data for furfural adsorption onto BFA. Adsorption of furfural on BFA is favorably influenced by a decrease in the temperature of the operation. Values of the change in entropy (ΔS ⁰) and heat of adsorption (ΔH ⁰) for furfural adsorption on BFA were negative. The high negative value of change in Gibbs free energy (ΔG ⁰) indicates the feasible and spontaneous adsorption of furfural on BFA.     

染料聚集态中空穴传递的顺磁共振研究

本文应用了顺磁共振波谱技术,研究了染料J-聚集体对染料正空穴俘获电子的影响。 实验所用乳剂是未经化学增感的溴化银(AgBr),染料用量2.5×10~(-4)摩尔染料/摩尔银。涂片厚度为3微米左右。     

预处理对染料生产模拟废水可生化性的影响

本试验采用臭氧氧化法、Fenton法和微电解法对染料模拟废水进行预处理,用经过驯化的微生物和瓦勃呼吸仪检测染料的可生化性,分析预处理对染料可生化性的影响,并通过紫外-可见吸收光谱分析染料结构变化与可生化性的关系。实验结果表明：实验染料结构中的偶氮基和苯环对染料的可生化性有显著的影响;三种预处理方法均可不同程度地破坏染料的结构,提高染料的可生化性;臭氧预处理时,溶液pH、处理时间对预处理结果有显著影响。     

铁炭微电解—亚铁还原氧化法处理花菁废水的研究

研究了微电解 亚铁还原氧化法在处理花菁废水上的应用 ,结果显示 ,经过处理 ,废水色度的去除率 >97% ,化学需氧量 (COD)的去除率 >90 % .研究了影响处理效果的因素 ,对于废水中有机物的去除、脱色以及废水可生化性的提高进行了探讨 ,并通过紫外 可见光谱和色质联用 (GC/MS)对处理前后的废水组分进行了分析     

电Fenton方法在甲基橙染料废水中的试验研究

考察了均相EF-Feox法(牺牲阳极法)、均相EF-Fere法和非均相电Fenton(Fe2(MoO4)3-kaolin-450)法3种电Fenton法对甲基橙偶氮染料废水的降解效果,对比了各反应体系的优缺点。与均相EF-Feox体系和均相EF-Fere体系相比,非均相电Fenton-Fe2(MoO4)3-kaolin-450体系对甲基橙的降解效果最好。当电流密度为65 mA/cm2、Fe2(MoO4)3-kaolin-450催化剂的加入量为6.6 g/L、初始pH为4.34、50 mmol/L的Na2SO4作为电解质、甲基橙的初始质量浓度为100 mg/L,甲基橙的COD去除率和脱色率分别可以达到92.48%和99.3%。将此方法应用于铬蓝黑R、橙黄Ⅱ、以及吩噻嗪类物质亚甲基蓝等染料废水体系中,同样条件下电解10 min,3者的脱色率均可以达到93%以上,说明此方法在染料废水处理中具有普遍适用性。