泥炭对溶液中铬的吸附及其在制革废水处理中的应用

经初步处理的泥炭可通过吸附去除制革废水中的Cr(Ⅲ ) ,在不同的振荡时间、Cr(Ⅲ )浓度、吸附剂用量和不同的pH条件下 ,泥炭吸附和去除Cr(Ⅲ )的效果有很大差异 .Cr(Ⅲ )在 1 0— 40mg·l- 1 范围内 ,最大去除率为 73 5 %— 88 2 % ,对应的吸附剂用量为 6 6—8 0g·l- 1 .铬液的初始pH <4 5时 ,Cr(Ⅲ )的去除为吸附过程 ,pH3 6时达到最高值 ;pH >4 5后 ,为沉淀过程 .废铬液中的杂质成分与Cr(Ⅲ )产生竞争吸附 ,使去除率略有降低 .经二次吸附后 ,废水可达到排放标准 .但Cr(Ⅲ )吸附的复杂性 ,使泥炭解吸率较低 .     

掷孢酵母吸附去除铬的性能研究

通过菌种培养、分离与筛选 ,获得一株对铬具有很强还原与吸附性能的掷孢酵母(Sporobolomycetaceaesp ) .该菌株适宜的吸附pH值是 6— 9,1g培养 60h的菌体在 2 0mlpH 7的 1 5mg·l- 1 铬液中 ,吸附 8h后 ,对铬的去除率最高达到 1 0 0 % .在浓度分别为 1 5 ,30 ,5 0 ,1 0 0 ,30 0mg·l- 1 的铬液中 ,每克菌体对铬的吸附量与对数曲线y=1 72 5 8ln(x) - 2 0 9 49相吻合 ,相关系数为 0 9889,对吸附后菌体破壁测得细胞质内含铬量最高 ,达 65 5 % .通过扫描电子显微镜发现 ,处理 1 5mg·l- 1 铬液 8h后 ,菌体细胞壁的表面结构不发生形态变化     

改性竹炭颗粒对水溶液中孔雀绿的吸附动力学研究

用不同的酸碱溶液处理竹炭,研究改性竹炭颗粒对水溶液中孔雀绿的吸附效果,再对筛选出的竹炭颗粒进行吸附动力学试验,并用准二级动力学模型和颗粒扩散模型对试验数据进行拟合,在此基础上进一步探讨影响吸附过程的因素。试验结果表明,用0.5 mol.L-1NaOH溶液处理过的竹炭颗粒吸附效果最佳,最大吸附量可达9.96 mg.g-1。颗粒扩散模型能更好地描述吸附动力学过程。竹炭颗粒的质量增加会降低孔雀绿分子的扩散速率;孔雀绿溶液的初始浓度增加则提高孔雀绿分子的扩散速率;颗粒直径、搅拌速度以及溶液的初始pH值也会影响吸附过程。     

改性活性炭对有机物的吸附性能

研究了表面改性对活性炭吸附各种有机物性能的影响,研究发现,硝酸氧化可显著增加活性炭表面酸性基团的含量,提高了活性炭的表面亲水性,降低pHpzc值,并造成活性炭的结构塌陷和比表面积的减少,因而对活性炭吸附水中的苯酚、苯胺、腐殖酸、氯仿、四氯化碳等有机物的性能产生明显影响,以去除水中有机污染物为目的的活性炭表面改性的方向应为：减少表面内酯基及竣基等含氧官能团的含量,增加活性炭表面的疏水性。     

市售绿茶自混合水溶液中吸附除去铬（Ⅵ）的研究

本文探讨了国产茶叶（市售云南产绿茶）的结构、成份和溶解，以及在不同浓度、时间、ｐＨ、温度的条件下，自混合溶液中大量吸附铬（Ⅵ）的特性。结果表明，浸泡过的茶叶对Ｃｒ（Ⅵ）的吸附率略低于未泡茶样，在一定条件下，Ｃｒ（Ⅵ）的吸附量可达到４．９６ｍｇ／ｇ。我们建议在这复杂体系中，用离子交换吸附过程形成表面配合物，以及发生化学作用的综合吸附机理来解释。     

硝化褐煤对铬离子溶液的吸附研究

利用硝酸与龙口褐煤反应制得硝化褐煤,使其有效吸附质腐植酸含量提高。用该湖化褐煤对铬离子进行吸附试验,研究吸附剂的吸附量、吸附动力学、吸附模型和溶液的pH值对吸附的影响。结果表明：硝化褐煤对铬离子具有良好的吸附特性,其静态等温吸附符合Langmuir等温议程。     

阳离子表面活性剂用量对改性沸石吸附铬酸根的影响

用不同量阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)对天然沸石改性,并制备不同改性程度的改性沸石,测定沸石对CTAB的吸附量,比较几种沸石对铬酸根的吸附性能及其与改性沸石胶体Zeta电位的关系,探讨沸石对铬酸根的吸附机制及沸石再生后对铬酸根的吸附能力.结果表明,随着CTAB加入量的增加,它在沸石表面的吸附量显著增加,制备的改性沸石对铬酸根吸附性能显著提高.改性后沸石胶体的Zeta电位由负变正,而且随着CTAB用量的增加,Zeta电位正值增加.铬酸根在改性沸石表面的吸附量随离子强度增加而减小,而且改性沸石吸附的铬酸根大部分可以被中性盐解吸,说明铬酸根的吸附以静电作用机制为主.改性剂用量在0.15～0.3 mol·kg-1范围内,改性沸石再生后仍对铬酸根有很好的吸附性能,可以循环使用.     

生物吸附剂的制备及其对铬的吸附性能

通过对吸附时间、吸附液pH值、溶液含铬浓度与菌丝球投加量的效应值与极值进行正交分析 ,确定出影响生物吸附效果的各因素依次是 :吸附时间→吸附液pH值→菌丝球投加量→铬浓度 .实验筛选出了两个对铬具有良好吸附性能的菌种 :黄曲霉 (Aspergillusflavus)、曲霉属 (Aspergillussp .) .在吸附 8h的条件下 ,它们对含铬 1 5mg·l- 1的吸附液除铬率分别达 6 7 1 %和 71 2 % ,两者的最佳吸附条件是 :pH =5 ,铬菌投加比为 5mg·g- 1.以这两种霉菌为主 ,通过吸附性能实验 ,探讨了多种因素对生物吸附剂除铬性能的影响 .     

粘土改性条件的研究Ⅱ.沸石的改性

考察了改性沸石的CTMAB加入量、CTMAB溶液浓度和吸附时间对CTMAB吸附量的影响 .测得沸石对CTMAB的饱和吸附容量为 6 5 0 0± 1 0 0mg·1 0 0g- 1沸石 ,明显高于改性膨润土的饱和吸附量 ,吸附符合Langmuir吸附特征 . 2 5℃时 ,当CTMAB的加入量为沸石饱和吸附容量的 1 1— 1 2倍 ,CTMAB溶液浓度≥ 1 6mg·ml- 1,吸附时间超过 6h时 ,沸石基本达到饱和吸附 .考察了有机沸石对于水中BTEX的去除效果 .并对沸石和膨润土的性质进行了比较 .     

The Adsorption of Lead and Copper from Aqueous Solution on Modified Peat–Resin Particles

Raw peat was modified with sulfuric acid, then mixed modified with resin to prepare the modified peat–resin particles. Using the batch experimental systems, the removal of heavy metals (copper and lead) on the modified peat–resin particles was investigated. The data of the adsorption isotherm could be fitted by the Langmuir equation well. The adsorption rate of heavy metals on modified peat–resin particles was very swift. The removal processes of heavy metals on modified peat–resin particles could be well described by pseudo-second order model. The adsorption rate of lead was affected by the initial heavy metal concentration, initial pH, particle size, agitation speed and particle mass. In the adsorption of heavy metals (lead and copper) on the modified peat–resin particles, ion exchange was the major reaction mechanism. Desorption data showed that the lead adsorbed by modified peat–resin particle could be desorbed by 0.5 N or 1.0 N HNO₃. The desorption rate was swift. The experiments indicated that the modified peat–resin particles have great potential for the removal of heavy metals from wastewater.     

改性活性氧化铝除磷性能的试验

为提高活性氧化铝对废水中磷的去除效果,以硫酸铝为改性剂,采用浸渍法对其进行改性;测定了改性前后活性氧化铝的比表面积及孔容孔径;考察了吸附时间、pH、废水初始浓度、改性剂投加量等因素对去除废水中磷的影响;探讨了改性活性氧化铝对磷的吸附机理.结果表明,改性后活性氧化铝的比表面积为398.364 m2/g,提高了14.22%...     

泥炭和褐煤对Zn^2＋,Cu^2＋,Pb^2＋等重金属离子的吸附特征

利用天然有机吸附剂泥炭和褐煤对重金属离子Ｚｎ＾２＋，Ｃｕ＾２＋，Ｐｂ＾２＋的单组分水溶液进行吸附研究。对吸附模型，吸附时间，不同吸附剂投放量，金属离子种类等给予表征，基本符合Ｌａｎｇｍｕｉｒ吸附等温线。     

Removal of sulfadiazine from aqueous solution on kaolinite

The adsorption of sulfadiazine onto kaolinite clay as an alternative adsorbent was examined in aqueous solution, hnpacts of the contact time, pH, temperature, ionic strength and coexistent surfactants on the adsorption process were evaluated. The pH significantly influenced the adsorption process, with adsorption being promoted at lower pH due to the cation exchange mechanism. Decreasing ionic strength in the solution was favorable for adsorption, and the addition of cationic and anionic surfactants had negative effects on the adsorption capacity of sulfadiazine on kaolinite. Kinetic experiments showed that the adsorption followed the pseudo-second-order model. The equilibrium adsorption was well described by both Freundlich and Dubinin-Radushkevich （DR） models. According to the DR model, the adsorption mechanism was determined by cationic exchange and weak physical forces. The thermodynamic study showed that sulfadiazine adsorption onto kaolinite was a sponta- neous and endothermic reaction.     

Adsorption of cadmium from aqueous solution using Rooibos shoots as adsorbent

The use of Rooibos shoots, a natural adsorbent, for cadmium removal from wastewater is proposed. The effects of initial pH, adsorbent dosage, contact time, and initial concentration were investigated in the batch adsorption mode. The optimum pH was found to be 5.5. Isotherm and kinetic data were modeled; the data fitted best to the Freundlich model, and, kinetically, the adsorption was of pseudo-second order as shown by the high R² value of 0.9928 along with close agreement between the experimental q_e (13.9 mg g^?1) and calculated q_e (14.24 mg g^?1) values. The studied biomass material was found to be effectively used for removal of cadmium from contaminated mine wastewater.     

Adsorption of methylene blue onto activated carbon derived from periwinkle shells: kinetics and equilibrium studies

Periwinkle shell, an abundant and inexpensive natural resource, was used to prepare activated carbon by physicochemical activation with potassium hydroxide (KOH) and carbon dioxide (CO₂) as the activating agents at 850 °C for 2 h. The adsorption equilibrium and kinetics of methylene blue dye on such carbon were then examined at 25 °C. Adsorption isotherm of the methylene blue (MB) on the activated carbon was determined and correlated with common isotherm equations. The equilibrium data for methylene blue adsorption well fitted to the Langmuir equation, with maximum monolayer adsorption capacity of 500.00 mg/g. Two simplified kinetic models including pseudo-first-order and pseudo-second-order equation were selected to follow the adsorption processes. The adsorption of methylene blue on activated carbon derived from periwinkle shell could best be described by the pseudo-second-order equation. The kinetic parameters of this best-fit model were calculated and discussed.     

The Effects of Acidity on Carbon Fluxes from Ombrotrophic Peat

Replicate intact peat/vegetation monoliths were collected along a pollution gradient in the UK and subjected over one year to 1200 mm of simulated rainfall of the same chemical composition as they received in the field. Drainage water was analysed periodically for DOC and pH, and the decomposition rates of Calluna vulgaris and Eriophorum angustifolium leaves were measured, as well as soil atmosphere CO₂ contents and peat matric potentials. the chemical characteristics of the peats as initially sampled from the field also were determined. the results suggest that acidic precipitation has induced chemical changes in ombrotrophic peats, lowering their pH and base status, when due account is taken of calcium deposition or any mineral content. Greater DOC fluxes were observed from the more acid peats, and litter decomposition rates from these peats were reduced.     

Retention characteristics of Cu2+, Pb2+, and Zn2+ from aqueous solutions by two types of low lime fly ashes

The technical feasibility of utilization of fly ash as a low-cost adsorbent for the removal of metals from water has been studied. For two types of fly ashes, the retention capacities of copper, lead, and zinc metal ions have been studied. Contact time, initial concentration, and pH have been varied and their effect on retention mechanism has been studied. The dominant mechanisms responsible for retention are found to be precipitation due to the presence of calcium hydroxide, and adsorption due to the presence of silica and alumina oxide surfaces in the fly ash. First-order kinetic plots have revealed that the rate constant increases with increase in the initial concentration and pH. Langmuir adsorption isotherms have been plotted to study the maximum adsorption capacities for metal ions considered under different conditions. X-ray diffraction studies revealed the formation of new peaks corresponding to respective metal ions precipitates under alkaline conditions.     

天然沸石对溶液中氨氮吸附特性的研究

为了探讨天然沸石对NH4 的吸附规律,以浙江缙云出产的粒径为2~3.2mm的天然斜发沸石为实验材料,进行吸附等温线实验和吸附动力学实验。结果表明,实验沸石对NH4 的吸附等温线符合Langmuir公式,且对氨氮吸附量的极限值为1.624mol·kg-1;实验沸石对NH4 的吸附反应符合一级动力学方程,反应速率常数为0.1882h-1。通过监测溶液中各阳离子浓度的变化,可确定沸石晶体内与NH4 进行交换的主要离子为Ca2 和Na ,二者占交换总量的96%以上;在交换反应初期,出现了由于沸石晶体中的离子在固液两相中的再分配所造成的离子交换的不等量现象。