石油焦基高比表面积活性炭对废水中CODCr的吸附能力

探讨了高比表面积活性炭(HSAAC)吸附水中COD_Cr时,活性炭用量、pH值和吸附时间等因素对COD_Cr吸附量和去除率的影响。实验结果表明,HSAAC用量越大,去除COD_Cr效果越好。当HSAAC用量为2.0g·L^-1,pH=3时,去除率达到78%以上;在酸性条件下HSAAC对COD_Cr的去除效果较好;HSAAC对废水中COD_Cr的吸附发生在前30min;COD_Cr浓度低于60mg·L^-1时,处理后COD_Cr的残余质量浓度低于地表水环境质量Ⅰ类标准(15mg·L^-1)。用碱再生HSAAC,一次再生率达94.22%,二次再生率达到了86.90%。说明高比表面积活性炭在适宜条件下对COD_Cr具有较好的吸附性能和良好的再生效果。     

活性小球藻对铅离子的吸附与解吸特征研究

研究了活性小球藻对Pb^2＋的生物吸附、解吸及其机理。结果表明,培养至指数生长期的小球藻对Pb^2＋的吸附能力最强,吸附率可达75％。吸附液的pH值在7左右,小球藻对Pb^2＋有较好的吸附作用,吸附率可达80％。吸附的动力学实验表明,在小球藻对Pb^2＋吸附的起始阶段,吸附速度较快,10min即可达到平衡。研究还表明,加强光照可以促进小球藻对Pb^2＋的吸附在一定的浓度范围内,小球藻对Pb^2＋的吸附符合Freundlich等温吸附模型。在解吸实验中,用EDTA和HCI作为解吸剂的解吸率可分别达到近80％和60％,可以有效解吸被吸附的Pb^2＋。     

新月藻生物吸附Pb2+影响因素的研究

对新月藻生物吸附Pb^2 的影响因素作了初步研究,实验表明,在新月藻的指数生长期和静止期加入Pb^2 时,Pb^2 的去除率较高;当藻细胞密度一定时,随着Pb^2 浓度的增加,其去除率增大,当Pb^2 浓度一定时,随着藻细胞密度的增加,新月藻对Pb^2 的去除率增大;pH对Pb^2 吸附影响不大,在pH5-9的范围内,Pb^2 去除率在60%以上。     

再力花残体活性炭的制备及对结晶紫的吸附

以多年生水生植物再力花残体为原料,磷酸为活化剂制备活性炭,其BET比表面积达1174.13 m2·g-1,微孔面积为426.99 m2·g-1,平均孔径为3.23 nm.考察了不同pH、结晶紫初始浓度、吸附时间和吸附温度下,活性炭对结晶紫的吸附性能.结果表明:吸附量基本不随pH变化;吸附过程主要分为快速吸附和慢速吸附2个阶段,符合伪二级动力学方程;在温度为293、303、313 K条件下,吸附过程更符合Langmuir等温吸附方程,最大吸附量分别为409.83、425.53和438.59 mg.g-1,且吸附是一个熵增的自发吸热过程.     

皂化麦麸对锌的吸附性能

以麦麸制备生物吸附剂研究其对重金属Zn~(2+)的吸附作用。利用DPS软件进行回归正交试验,分析pH、麦麸生物吸附剂加入量、温度、初始Zn~(2+)浓度和吸附时间对吸附率影响,得出最佳吸附条件,与活性炭、麦麸纤维吸附效果作比较,对皂化麦麸进行解吸;同时研究等温吸附和吸附动力学,电镜和傅立叶红外光谱图研究吸附机理。吸附时间3 h、加入量0.2 g、pH值9、70℃、Zn~(2+)溶液浓度为80 mg/L时,吸附率达最大值,且低浓度时,麦麸生物吸附剂吸附效果优于活性炭与麦麸纤维,至少可以进行四次重复利用。麦麸生物吸附剂对Zn~(2+)吸附符合Freundich等温式,更适合拟二级动力学模型,即符合多分子层多位点物理化学混合吸附。SEM知皂化麦麸有明显褶皱,疏松多孔,表面积增大;FTIR分析出,麦麸生物吸附剂含-OH、-NH-、-C≡C-、-C≡N等多个官能团,对吸附过程起到很大的作用。     

铅离子的生物吸附动力学及吸附热力学研究

目的：研究非活性深红酵母（Rhodotorula rubra）对重金属离子Pb^2＋的生物吸附热力学和动力学特性。方法：采用恒温摇床振荡吸附的实验方法,研究Pb^2＋生物吸附的动力学和热力学,并以适当的数学模型对实验数据进行拟合;对吸附前后的酵母进行红外光谱及X射线光电子能谱分析。结果：在20℃～45℃温度范围内,吸附5min时即达到了饱和吸附量的80%以上,2h左右达到平衡;深红酵母对Pb^2＋的生物吸附过程适宜用Elovich方程来描述;由二级动力学方程计算的生物吸附活化能为21.56kJ/mol;生物吸附平衡可用Langmuir等温式、Freundlich等温式及Dubinin-Radushkevich等温式来描述,拟合相关系数均接近0.99;Langmuir方程计算所得ΔH^0为13.93kJ/mol。结论：深红酵母对Pb^2＋的生物吸附是非均相的扩散过程,由快速吸附和慢速吸附两个阶段组成,以物理吸附为主,并伴随有化学吸附。     

巴旦木壳基活性炭的制备及其对亚甲基蓝吸附的研究

以巴旦木壳为原材料，采用KOH活化法制备出了比表面积为1 763 m²/g的活性碳，通过SEM对样品结构进行表征，并研究了活性炭对亚甲基蓝的吸附效果。结果表明，KOH活化法制备的活性炭具有丰富的微孔结构，其对亚甲基蓝的最大平衡吸附量为524 mg/g，最佳吸附p H为6.0，吸附过程符合Langmiur方程描述的单分子吸附过程，其吸附动力学可用准二级动力学模型来表述。     

赣南油茶壳活性炭制备及对重金属元素铅和锰的吸附性分析

油茶壳因含有大量的纤维素而用于制备活性炭。本研究以油茶壳为原料,使用碳酸钾活化,在马弗炉中制备活性炭,并以亚甲基兰和碘吸附量作为评价指标考察了制备的活性炭产品吸附能力并优化了油茶壳活性炭的制备工艺。以重金属元素铅和锰为吸附元素,分别考察了制备的油茶壳活性炭对重金属元素铅和锰单一元素和混合元素的吸附能力。实验结果表明,油茶壳活性炭具有良好的吸附性能,对水中单一元素铅的吸附量为1 100μg/g,对单一元素锰的吸附量为250μg/g,对这两种混合元素吸附作用时,铅会竞争性地占据吸附位点,致使锰元素吸附量非常少。通过对比实验证明,油茶壳活性炭对亚甲基兰的吸附和碘吸附量均大与椰壳活性炭,对水中铅元素的吸附作用大于锰元素的吸附作用,作为新型吸附剂,该活性炭能用于水中重金属元素特别是铅元素的吸附。     

活性炭对抗毒素中防腐剂含量的影响

为了解使用活性炭去除抗毒素原液的不可溶性杂质试验中对防腐剂含量所产生的影响。方法比较不同用量活性炭吸附抗毒素原液中防腐剂的损失情况;按最低活性炭使用量,观察整个实验过程中防腐剂含量的变化。结果分别以20 g/L、30 g/L、50 g/L活性炭经2 h吸附后,防腐剂量的损失均达到98%;在20 g/L活性炭使用量吸附4 h的试验中,防腐剂量的损失主要发生在最初的1 h。结论使用活性炭去除抗毒素原液中的不可溶性杂质试验中,由于活性炭较强的吸附作用,从而对防腐剂含量产生了很大的影响。     

柠檬渣吸附磷的研究

为了研究柠檬渣对磷的吸附,利用H_2SO_4和CaCl_2溶液对柠檬渣进行了改性,并采用L_(16)(4~5)正交实验进行了优化。测试了吸附剂的比表面积、孔容与孔径等性能,并利用电镜和能谱(SEM/EDS)对吸附剂进行了表征。实验结果表明吸附影响因素的最优组合为CaCl_2溶液的质量浓度为20%、溶液pH值为8.5、吸附时间为120min和吸附温度为25℃,在此最优条件下柠檬渣吸附磷的吸附率可达到93.6%,因素的主次关系依次为CaCl_2质量浓度吸附时间吸附温度pH值,且CaCl_2溶液的质量浓度具有显著性。柠檬渣经改性后比表面积增加了近4倍,孔容、孔径和碘吸附值变化不大,灰分率减少了近70%;吸附后柠檬渣中含有P元素,但形成的峰都不高。     

水鳖叶片对不同浓度Pb2+胁迫的生理和结构响应

研究了不同浓度Pb~(2+)胁迫(0、10、20、30和50 mg·L~(-1))对水鳖叶绿素含量、可溶性蛋白含量、抗氧化系统、活性氧产生速率和细胞超微结构的影响。结果表明:随着Pb~(2+)浓度的增加,水鳖叶片总叶绿素、叶绿素a/b值、可溶性蛋白含量和CAT活性逐渐下降;SOD、POD、APX、GR活性、抗坏血酸(AsA)和谷胱甘肽(GSH)含量先升后降;O_2~-·产生速率、H_2O_2、丙二醛(MDA)和可溶性糖含量呈上升趋势;不连续聚丙烯酰胺凝胶电泳(SDS-PAGE)显示,Pb~(2+)处理后,分子量为1 6.3kDa、55.0kDa的多肽含量减少,高浓度处理下分子量为23.1kDa、75.8kDa、94.0kDa的多肽条带消失;电镜观察发现,Pb~(2+)对水鳖叶片细胞的叶绿体、线粒体和细胞核造成严重损伤。Pb~(2+)破坏了水鳖正常代谢所需的生理和结构基础,打乱了代谢平衡,最终导致植物的衰亡。     

Biosorption of hexavalent chromium using biofilm of <Emphasis Type="Italic">E. coli</Emphasis> supported on granulated activated carbon

The optimization of hexavalent chromium biosorption has been studied by using three different biosorbents; biofilm of E. coli ASU 7 supported on granulated activated carbon (GAC), lyophilized cells of E. coli ASU 7 and granulated activated carbon. Supporting of bacteria on activated carbon decreased both the porosity and surface area of the GAC. Significant decrement of surface area was correlated to the blocking of microspores as a result of the various additional loads. The experimental data of adsorption was fitted towards the models postulated by Langmuir and Freundlich and their corresponding equations. The maximum biosorption capacity for hexavalent chromium using biofilm, GAC and E. coli ASU 7 were 97.70, 90.70, 64.36 mg metal/g at pH 2.0, respectively. Biosorption mechanism was related mainly to the ionic interaction and complex formation. Based on the experimental conditions, the presence of bacteria could be enhanced the capacity of activated carbon to adsorb hexavalent chromium ions from aqueous solutions.     

ZnCl2-Modified Activated Carbon from Biomass Coir Pith for the Removal of 2-Chlorophenol by Adsorption Process

Coir pith, a waste biomass, from coconut coir industry was used to prepare activated carbon with ZnCl₂ and employed for the removal of 2-chlorophenol (2-CP) from aqueous solution and wastewater. Zinc chloride–activated coir pith carbon (ZnCPC) was prepared by mixing coir pith with ZnCl₂ in the ratio 2:1 and carbonized at 700°C for 1 h. ZnCPC was characterized using standard physicochemical methods, Brunaver, Emmett, and Teller (BET) surface area, and scanning electron microscopy (SEM) studies. Batch mode adsorption studies were carried out to evaluate the effect of contact time, initial concentration, adsorbent dose, pH, and temperature. The Langmuir adsorption capacity Q ₀ was found to be 149.3 mg g^?1. Kinetic studies showed that the adsorption obeyed second-order and Bangham's model. Equilibrium adsorption data fit better into Langmuir, Freundlich, and D-R isotherms. pH effect and desorption studies showed that ion-exchange mechanism was involved in the adsorption process. Effect of temperature was not significant. Quantitative removal of 2-CP from synthetic wastewater was also achieved. ZnCPC is economically effective compared to commercial activated carbon, because the raw material is abundantly and freely available and it can be used effectively in the treatment of water contaminated with 2-CP.     

Charcoal and activated carbon as adsorbate of phytotoxic compounds – a comparative study

This study compares the potential of natural charcoal from Scots pine ( Pinus sylvestris L.) and activated carbon to improve germination under the hypothesis that natural charcoal adsorbs phytotoxins produced by dwarf-shrubs, but due to it's chemical properties to a lesser extent than activated carbon. Activated carbon has been used in many bioassays as an adsorbate to clean aqueous solutions.
We used aqueous extracts from young leaves of Calluna vulgaris (L.) Hull and Vaccinium myrtillus (L.) as phytotoxin sources in two different concentrations (10 and 14 gr. of dried leaves in 100 ml distilled water). Germination of pine seeds was prevented by the higher concentration of both species, while the lower ones did not show significantly reduced germination. Both ericaceous species showed a very similar potential to prevent germination of Scots pine seeds.
Supplemented carbon (activated carbon, powdered or granulated pine charcoal) restored germination in strong extracts. Adding activated carbon resulted in germination of almost 100%. With pine charcoals added, lower germination percentages were observed. The charcoal powder was more effective (60% for C. vulgaris ; 28% for V. myrtillus ) than the charcoal granulate (30% and 16%, respectively) in restoring germination.
Chemical and surface analysis of the three carbon supplements revealed that activated carbon had by far the biggest active surface area (641 m² g⁻¹), and thus many more cavities to bind phytotoxins than natural charcoal (total surface area of 142 m² g⁻¹).
We conclude, that charcoal produced by forest fires can have a positive effect on seed germination, but to a much lesser extent than activated carbon. Previous studies, which used activated carbon as an equivalent for charcoal, overestimated the effect of charcoal on germination.     

Production and comparison of high surface area bamboo derived active carbons

High surface area activated carbons have been produced from the natural biomaterial bamboo, using phosphoric acid as the activating agent. The effects of phosphoric acid impregnation ratio, activation temperature, heating rate on the carbon surface area, porosity and mass yield are presented. Three of these bamboo derived active carbons, surface areas 1337, 1628 and 2123m(2)/g were assessed for their ability to adsorb Acid Red 18 dye from aqueous solution; these results were compared with three conventional adsorbents: activated carbon F400, bone char and peat. Isotherm data were analysed using Langmuir, Freundlich, Redlich-Peterson and Langmuir-Freundlich isotherms. Different isotherms provided the best fit correlations to the adsorption experimental data but the Langmuir-Freundlich equation provided the best overall correlation of data. The adsorption capacities of two of the selected bamboo derived carbons were much greater than the capacities of the other three adsorbents.     

Adsorption of Cd(II) ions from aqueous solutions using activated carbon prepared from olive stone by ZnCl2 activation

This study is aimed to remove Cd(II) ions from aqueous solutions by adsorption. As adsorbent, activated carbon prepared from olive stone, an agricultural solid by-product was used. Different activating agent (ZnCl(2)) amounts and adsorbent particle size were studied to optimize adsorbent surface area. The adsorption experiments were conducted at different parameters such as, adsorbent dose, temperature, equilibrium time and pH. According to the experiments results, the equilibrium time, optimum pH, adsorbent dosage were found 60 min, pH > 6 and 1.0 g/50 ml respectively. The kinetic data supports pseudo-second order model and intra-particle model but shows very poor fit for pseudo-first order model. Adsorption isotherms were obtained from three different temperatures. These adsorption data were fitted with the Langmuir and Freundlich isotherms. In addition, the thermodynamic parameters, standard free energy (DeltaG(0)), standard enthalpy (DeltaH(0)), standard entropy (DeltaS(0)) of the adsorption process were calculated. To reveal the adsorptive characteristics of the produced active carbon, BET surface area measurements were made. Structural analysis was performed using SEM-EDS. The resulting activated carbons with 20% ZnCl(2) solution was the best sample of the produced activated carbons from olive stone with the specific surface area of 790.25 m(2)g(-1). The results show that the produced activated carbon from olive stone is an alternative low-cost adsorbent for removing Cd(II).     

Removal of molybdate from water by adsorption onto ZnCl2 activated coir pith carbon

Removal and recovery of molybdate from aqueous solution was investigated using ZnCl2 activated carbon developed from coir pith. Studies were conducted to delineate the effects of contact time, adsorbent dose, molybdate concentration, pH and temperature. Two theoretical adsorption isotherms, namely, Langmuir and Freundlich were used to describe the experimental results. The Langmuir adsorption capacity (Q0) was found to be 18.9 mg molybdate/g of the adsorbent. Adsorption followed second order kinetics. Studies were performed at different pH values to find out the pH at which maximum adsorption occurred. The pH effect and desorption studies showed that ion exchange and chemisorption mechanism were involved in the adsorption process. Thermodynamic parameters such as DeltaG0, DeltaH0 and DeltaS0 for the adsorption were evaluated. Effect of foreign ions on adsorption of molybdate has been examined. The results showed that ZnCl2 activated coir pith carbon was effective for the removal and recovery of molybdate from water.     

Removal of Cr(VI) from aqueous solutions by adsorption onto hazelnut shell activated carbon: kinetic and equilibrium studies

The adsorption Cr(VI) from aqueous solutions onto hazelnut shell activated carbon was carried out by varying the parameters such as pH, initial Cr(VI) concentration and temperature. The experimental data fitted well to the pseudo first-order kinetic model and then the rate constants were evaluated. The Langmuir isotherm provided the best correlation for Cr(VI) onto the activated carbon. Adsorption capacity was calculated from the Langmuir isotherm as 170 mg/g at an initial pH of 1.0 for the 1000 mg/l Cr(VI) solution. Thermodynamic parameters were evaluated and the adsorption is endothermic showing monolayer adsorption of Cr(VI).     

Surface esterification of corn starch films: Reaction with dodecenyl succinic anhydride

Surface of corn starch films was modified through esterification using dodecenyl succinic anhydride (DDSA) as reactant. The effects of reaction temperature and time, concentration of alkaline aqueous solution for activating starch, concentration of ethanol diluted DDSA, and time of alkaline aqueous solution treatment on the physical properties related to material’s hydrophilic nature, such as moisture absorption and surface water contact angle, were investigated. It was found that the surface esterification modification significantly reduced the moisture sensitivity and surface hydrophilic character of starch film. Due to the hydroxyl groups in the film surface layer were reacted with DDSA, the equilibrium moisture content of the starch film under 95% RH declined 22% and the surface water contact angle increased up to 82% after surface esterification modification.