花生壳粉作为生物吸附剂去除水溶液中偶氮染料的研究

用低值的花生壳粉作为生物吸附剂对苋菜红、日落黄两种偶氮染料进行了吸附研究,目的是寻求经济的染料废水处理方法。考察了PH、染料浓度、吸附剂量、吸附剂粒径、离子强度和吸附时间等因素对染料吸附的影响,确定了最佳吸附条件。结果显示,初始pH2,两种偶氮染料的去除率较高。吸附等温线符合Langmuir和Freondlich模式,吸附过程符合准一级反应动力学方程。研究结果表明,花生壳是一种很有前途的偶氮染料废水处理生物材料。     

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。     

啤酒废酵母对镉离子的吸附研究

以啤酒酿造厂的啤酒废酵母为生物吸附剂,研究啤酒废酵母对Cd2 的生物吸附行为。利用原子吸收光谱法测定Cd2 含量。结果表明,啤酒废酵母吸附Cd2 受吸附时间、吸附温度、溶液pH值、酵母添加量和Cd2 起始浓度等因素的影响。实验确定了啤酒废酵母对Cd2 的最佳吸附条件。即:pH值6,Cd2 浓度为50mg/L,酵母添加量为1.0g/L,吸附温度25℃,吸附时间30min,此时啤酒废酵母对Cd2 的吸附量可达42.92mg/g干酵母。吸附Cd2 的啤酒废酵母用1.0mol/L的HCl解吸,解吸率达75.46%。对未吸附Cd2 的空白酵母和吸附Cd2 的酵母进行红外光谱分析,结果显示啤酒废酵母吸附Cd2 后羟基和羧基吸收峰发生明显变化,因此认为羟基和羧基在生物吸附中起着重要作用。     

两种大型真菌子实体对Cd2+的生物吸附特性

对两种多孔菌科大型真菌槐栓菌(Trametes robiniophila)和木蹄层孔菌(Fomes fomentarius)子实体生物吸附Cd²⁺的影响因素(包括吸附剂用量、初始pH、吸附时间、初始Cd²⁺浓度)和吸附特性进行分析。结果表明,槐栓菌和木蹄层孔菌对低浓度的Cd²⁺(10 mg/L)吸附的最适pH为6;Cd²⁺的去除率随吸附剂用量和吸附时间的增加而增大,槐栓菌和木蹄层孔菌均在吸附剂用量为2g/L时达到吸附平衡,槐栓菌在吸附时间为30 min时达到吸附平衡,而木蹄层孔菌在吸附时间为60 min时达到吸附平衡;槐栓菌和木蹄层孔菌对10 mg/L Cd²⁺的最大去除率分别为98%和94%。Langmuir等温吸附平衡模型比Freundlich等温吸附平衡模型能更好的拟合两种大型真菌对Cd²⁺的吸附过程;槐栓菌和木蹄层孔菌对10 mg/L Cd²⁺的最大吸附量分别为17.40 mg/g和8.91 mg/g。对实验数据进行动力学模型拟合可知,两种大型真菌对Cd²⁺的生物吸附过程均符合准二阶动力学模型。槐栓菌和木蹄层孔菌生物吸附低浓度Cd²⁺的化学反应机理可能为离子交换。     

铜离子和亚甲蓝在柠檬酸酯化麦草上的吸附行为

以固相酯化法制备一种具有羧基的柠檬酸改性麦草阳离子吸附剂.用批次实验法研究了不同实验条件下(pH值、吸附剂量、吸附质浓度和吸附时间)水溶液中铜离子和亚甲蓝在酯化麦草上的吸附行为.结果表明：溶液初始pH≥40时,铜离子和亚甲蓝达到最大吸附值.≥2.0 g·L^-1的酯化麦草能去除铜浓度为100 mg·L^-1溶液中96%的铜及亚甲蓝浓度为250 mg·L^-1溶液中99%的亚甲蓝.酯化麦草对铜离子和亚甲蓝的吸附符合Langmuir等温模型,其最大吸附能力分别为79.37 mg·g^-1和312.50 mg·g^-1.铜离子和亚甲蓝达到吸附平衡的时间分别为75 min和5 h,准一级和准二级反应动力学方程可分别描述酯化麦草对铜离子和亚甲蓝的吸附过程.     

根霉吸附水体中重金属铬与吸附机理的研究

以根霉RhizopusLH2死菌体为吸附剂进行水体中六价铬的吸附研究.结果表明,Cr(VI)的生物吸附最优条件为:温度28℃,pH为2;线性回归相关系数为0.98,符合Langmuir吸附等温线模型;傅立叶红外变换光谱分析推断吸附机理为质子化氨基在Cr(VI)的生物吸附中起主要作用.     

废啤酒酵母吸附水溶液中Cu2+的性能及机理研究

用废啤酒酵母吸附水溶液中Cu2+,考察了溶液pH值、Cu2+浓度和吸附时间对Cu2+吸附的影响。结果表明：废啤酒酵母吸附Cu2+在4-6个小时内达到吸附平衡,酸性条件利于吸附,以pH为5时最佳,吸附等温曲线符合Langmuir模式。用电位滴定及FTIR分析的方法确定生物吸附剂主要含有磺酸基、羧基及氨基等功能团。生物吸附剂对Cu2+的吸附以单分子层的化学吸附为主,功能团在不同的pH条件下呈现不同的电离性能,在吸附过程中发挥重要作用。     

胶质芽孢杆菌对Zn2+、Cd2+的生物吸附

目的:考察胶质芽孢杆菌对Cd2 、Zn2 的耐受能力.方法:通过改变培养条件及吸附条件研究胶质芽孢杆菌对Cd2 、Zn2 的生物吸附性能.在此实验基础上,在含有Cd2 、Zn2 的培养基中对胶质芽孢杆菌进行不同浓度梯度驯化,提高其对Cd2 Zn2 的生物富集能力.结果:胶质芽孢杆菌最大Cd2 耐受浓度在100mg·L-1左右,最大Zn2 耐受浓度在100～110mg·L-1.通过改变吸附条件,考察吸附时间、吸附pH值、菌体投加量对其生物吸附性能的影响,结果表明:当Cd2 、Zn2 浓度均为5mmol·L-1,菌投量分别为40.0gdry cell·L-1、29.8gdry cell·L-1时,胶质芽孢杆菌对Cd2 、zn2 的吸附率分别可达87.45%、97.50%.胶质芽孢杆菌经重金属离子浓度梯度驯化培养数代,经过8、9代的驯化,对Cd2 、Zn2 吸附性能均有改善.结论:胶质芽孢杆菌经过驯化,在适宜的吸附条件下可以对Cd2 、Zn2 进行有效的生物吸附,在处理重金属离子废水方面有潜在的应用前景.     

海水中主要无机阴离子对针铁矿吸附镉的影响

采用人工合成针铁矿作为吸附剂,通过序批式试验,研究了pH值以及海水中主要无机阴离子Cl-、SO42-卜、NO3-和HCO3-对Cd吸附的影响.结果表明:随pH值升高,针铁矿对Cd的吸附量显著增加;Cl-、SO42-和NO3-在pH8时抑制针铁矿对Cd的吸附;Cl-和SO42-在低pH值条件下促进Cd的吸附;HCO3-在pH 4～10范围内促进Cd吸附;pH8时,SO42-与Cd加入顺序的不同对吸附结果具有显著影响,先加入Cd时,Cd的吸附量明显大于先加入SO42-和Cd-、SO42-同时加入时Cd的吸附量.     

蛋白核小球藻对Pb(Ⅱ)和Cd(Ⅱ)的生物吸附及其影响因素

藻类吸附作用影响重金属在水生生态系统中的迁移过程及其环境行为。同时,利用藻类吸附能力是修复重金属污染水体和重金属废水处理的一项清洁、廉价和高效的技术。测定了蛋白核小球藻对Pb2+和Cd2+的吸附和脱附动力学,表明吸附是快速表面过程,吸附4 h后基本达到平衡,不易脱附。研究了蛋白核小球藻对Pb2+和Cd2+的吸附热力学,绘制了吸附等温线,并用Langmuir模型进行拟合,相关系数R2分别为0.9906和0.9827,计算得到最大吸附量分别为0.373 mmol Pb/g和0.249 mmolCd/g。考察了pH值、离子强度和温度等环境因素对蛋白核小球藻吸附Pb2+和Cd2+的影响。结果表明,蛋白核小球藻对Pb2+和Cd2+的吸附量在pH值5.0—6.0之间达到最大值,并随着溶液离子强度的增加而降低,随着溶液温度的升高而增加。温度的影响还表明,蛋白核小球藻对Pb2+和Cd2+的吸附是吸热过程。实验还考察了水体环境中普遍存在的溶解性有机质主要成分-富里酸的影响,表明富里酸会抑制蛋白核小球藻对Pb2+和Cd2+的吸附,重金属离子浓度较低时的抑制效果更明显,最大抑制率分别达到了34.2%和34.9%。由于其对重金属的较高吸附量和吸附本身快速完成的特性,蛋白核小球藻有望成为较理想的生物吸附剂,在重金属污染水体的生物修复及废水处理中发挥重要作用。     

Bioremediation of cadmium-contaminated water systems using intact and alkaline-treated alga (Hydrodictyon reticulatum) naturally grown in an ecosystem

Cadmium can enter water, soil, and food chain in amounts harmful to human health by industrial wastes. The use of intact and NaOH-treated dried algal tissues (Hydrodictyon reticulatum), a major ecosystem bio-component, for Cd removal from aqueous solutions was characterized. Cadmium biosorption was found to be dependent on solution pH, bioadsorbent dose, the interaction between pH and dose, contact time, and initial Cd concentration. The experimental results indicated that the biosorption performance of alkaline-treated algal tissues was better than that of intact tissues. The maximum biosorption capacities were 7.40 and 12.74 mg g^?1 for intact and alkaline-treated bioadsorbents, respectively, at optimum operating conditions. Biosorption reaches equilibrium after 24 and 240 minutes of contact, respectively, for alkaline-treated and intact bioadsorbents. Cadmium biosorption was best fitted to Langmuir isotherm model (R² ≈ 0.99) and the kinetic study obeyed the pseudo-second-order kinetic model, which suggests chemisorption as the rate-limiting step in the biosorption process. Alkaline-treated algal tissues can be used as a new material of low-cost bioadsorbent for continuous flow rate treatment systems.     

耐铅镉菌株的分离鉴定及其吸附能力

堆肥中添加生物钝化剂是当前降低粪便中重金属生物毒性最为有效的方式之一,为了进一步提高其钝化重金属的能力,文中获得了复合重金属高耐性的钝化剂菌株,并探究其生物学特性和吸附特征。采集猪粪堆肥样品并在改良的牛肉膏培养基中分离和筛选耐铅又耐镉的高耐性菌株,通过形态结合分子生物学鉴定该菌株。该菌株分别在不同pH、温度和盐浓度条件下培养获得其最适的生长条件,进而在该条件下分析其对铅镉吸附的特性。结果获得一株耐铅浓度为600 mg/L、镉浓度为120 mg/L的铅镉复合耐性菌株SC19,该菌株为西地西菌属,其最适生长环境为pH值7.0、温度37℃、盐浓度0.5%。培养36 h的稳定期SC19菌株在吸附时间30min时铅的去除率最高,对铅的最大去除率和吸附量分别为60.7%和329.13mg/g;培养8h的对数期在吸附时间30min时镉的去除率最高,对镉的最大去除率和吸附量分别为51.0%和126.19 mg/g。红外光谱分析显示,SC19菌株对铅镉离子的吸附主要是细胞表面的多种活性基团与金属离子发生络合作用。该研究揭示了SC19菌株有较好的二价态铅镉离子吸附能力,可为生物钝化重金属提供重要的微生物种质资源。     

Equilibrium and kinetics of biosorption of cadmium(II) and copper(II) ions by wheat straw

Biosorption equilibrium and kinetics of Cd(2+) and Cu(2+) ions on wheat straw, Triticum aestivum, in an aqueous system were investigated. Among the models tested, namely the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherms, the biosorption equilibrium for both Cd(2+) and Cu(2+) was best described by the Langmuir model. The Langmuir biosorption capacity for Cd(2+) was about 27% higher than that for Cu(2+). It was also found that biosorption of Cd(2+) and Cu(2+) by wheat straw followed second-order kinetics. The equilibrium amount of metal ions adsorbed onto the wheat straw increased with increasing of pH from 4.0 to 7.0, and the effect was more pronounced for Cd(2+) than for Cu(2+). The equilibrium adsorbed amount also increased with the initial concentration of the metal ions, as expected. On the other hand, an increase of temperature from 25 to 30 degrees C only enhanced the biosorption of Cd(2+) and Cu(2+) slightly. The apparent temperature independence and the strong pH dependence of the amount of metal ions adsorbed along with moderate mean free energies of biosorption (between 8.0 and 12.9 kJ mol(-1)) altogether indicate that biosorption of Cd(2+) and Cu(2+) by wheat straw might follow a chemisorption mechanism.     

Equilibrium isotherm studies for the uptake of cadmium and lead ions onto sugar beet pulp

The adsorption of Cd2+ and Pb2+ on sugar beet pulp (SBP), a low-cost material, has been studied. In the present work, the abilities of native (SBP) to remove cadmium (Cd2+) and lead (Pb2+) ions from aqueous solutions were compared. The (SBP) an industrial by product and solid waste of sugar industry were used for the removal of Cd2+ and Pb2+ ions from aqueous water. Batch adsorption studies were carried out to examine the influence of various parameters such as initial pH, adsorbent dose, initial metal ion concentration, and time on uptake. The sorption process was relatively fast and equilibrium was reached after about 70 min of contact. As much as 70-75% removal of Cd2+ and Pb2+ ions for (SBP) are possible in about 70 min, respectively, under the batch test conditions. Uptake of Cd2+ and Pb2+ ions on (SBP) showed a pH-dependent profile. The overall uptake for the (SBP) is at a maximum at pH 5.3 and gives up to 46.1 mg g(-1) for Cd2+ and at pH 5.0 and gives 43.5 mg g(-1) for Pb2+ for (SBP), which seems to be removed exclusively by ion exchange, physical sorption and chelation. A dose of 8 gL(-1) was sufficient for the optimum removal of both the metal ions. The Freundlich represented the sorption data for (SBP). In the presence of 0.1M NaNO3 the level of metal ion uptake was found to reach its maximum value very rapidly with the speed increasing both with the (SPB) concentration and with increasing initial pH of the suspension. The reversibility of the process was investigated. The desorption of Cd2+ and Pb2+ ions which were previously deposited on the (SBP) back into the deionised water was observed only in acidic pH values during one day study period and was generally rather low. The extent of adsorption for both metals increased along with an increase of the (SBP) dosage. (SBP), which is cheap and highly selective, therefore seems to be a promising substrate to entrap heavy metals in aqueous solutions.     

A general model for biosorption of Cd2+, Cu2+ and Zn2+ by aerobic granules

Aerobic granules are microbial aggregates with a strong and compact structure. This study looked into the feasibility of aerobic granules as a novel type of biosorbent for the removal of individual Cd(2+), Cu(2+) and Zn(2+) from aqueous solution. Based on the thermodynamics of biosorption reaction, a general model was developed to describe the equilibrium biosorption of individual Cd(2+), Cu(2+) and Zn(2+) by aerobic granules. This model provides good insights into the thermodynamic mechanisms of biosorption of heavy metals. The model prediction was in good agreement with the experimental data obtained. It was further demonstrated that the Langmuir, Freundlich and Sips or Hill equations were particular cases of the proposed model. The biosorption capacity of individual Cd(2+), Cu(2+) and Zn(2+) on aerobic granules was 172.7, 59.6 and 164.5 mgg(-1), respectively. These values may imply that aerobic granules are effective biosorbent for the removal of Cd(2+), Cu(2+) and Zn(2+) from industrial wastewater.     

Potential capacity of Beauveria bassiana and Metarhizium anisopliae in the biosorption of Cd2+ and Pb2+

In this study Beauveria bassiana and Metarhizium anisopliae were used as inexpensive and efficient biosorbents for Pb(II) and Cd(II) from aqueous metal solutions. The effects of various physicochemical factors on Pb(II) and Cd(II) biosorption by B. bassiana and M. anisopliae were studied. The optimum pH for Cd(II) and Pb(II) biosorption by two fungal species was achieved at pH 6.0 for Pb(II) and 5.0 Cd(II) at a constant time of 30 min. The nature of fungal biomass and metal ion interactions was evaluated by Fourier transform infrared. The maximum adsorption capacities (q(max)) calculated from Langmuir isotherms for Pb(II), and Cd(II) uptake by B. bassiana were 83.33±0.85, and 46.27±0.12 mg/g, respectively. However, the q(max) obtained for Pb(II) uptake by M. anisopliae was 66.66±0.28 mg/g, and 44.22±0.13 mg/g for Cd(II). B. bassiana showed higher adsorption capacity compared to M. anisopliae. The data obtained imply the potential role of B. bassiana and M. anisopliae for heavy metal removal from aqueous solutions.     

Biosorption of pentachlorophenol from aqueous solutions by a fungal biomass

This study focuses on the use of non-viable Aspergillus niger biomass, for the biosorption of pentachlorophenol (PCP) from aqueous solutions. Various forms of the biomass-autoclaved and chemically conditioned, were tested for their potential in the removal of PCP from aqueous solutions. It was found that PCP removal was pH dependent; PCP removal decreased with the increase in pH for all type of biomass, except for cetyltrimethylammonium bromide (CTAB) biomass. For CTAB biomass, a near complete removal of PCP was observed at all pHs. Therefore, CTAB biomass was used in further studies. PCP removal was rapid, with an equilibrium time of 2h. The rate of adsorption kinetics was well described by a pseudo-second order model. Isotherm models of the type one and two parameter models were found to fit the isotherm data. PCP biosorption was found to be exothermic in nature; the amount of PCP sorbed decreased with an increase in temperature. Desorption was carried out using deionized water, dilute HCl and dilute NaOH, and it was found that most of the PCP was irreversibly bound to the biomass. The addition of inorganic salts did not affect the removal of PCP from aqueous solutions. Among the surface functional groups present on the biomass, carboxyl, amide and hydroxyl groups seem to have played a role in PCP biosorption. It was concluded that CTAB treated biomass was an excellent adsorbent for the removal of PCP from aqueous solutions.     

Biosorption of cadmium and lead ions by ethanol treated waste baker's yeast biomass

The biosorption of cadmium and lead ions from artificial aqueous solutions using waste baker's yeast biomass was investigated. The yeast cells were treated with caustic, ethanol and heat for increasing their biosorption capacity and the highest metal uptake values (15.63 and 17.49 mg g(-1) for Cd(2+) and Pb(2+), respectively) were obtained by ethanol treated yeast cells. The effect of initial metal concentration and pH on biosorption by ethanol treated yeast was studied. The Langmuir model and Freundlich equation were applied to the experimental data and the Langmuir model was found to be in better correlation with the experimental data. The maximum metal uptake values (qmax, mg g(-1)) were found as 31.75 and 60.24 for Cd(2+) and Pb(2+), respectively. Competitive biosorption experiments were performed with Cd(2+) and Pb(2+) together with Cu(2+) and the competitive biosorption capacities of the yeast biomass for all metal ions were found to be lower than in non-competitive conditions.     

活体微藻吸附水体中Cd2+的性能特征

【目的】藻类对重金属吸附和吸收是重金属进入食物链的重要渠道之一。研究活体微藻对水体中Cd~(2+)的吸附性能和吸附机理,旨在为Cd~(2+)等重金属离子进入水体后的去向及去除提供理论依据。【方法】选取地表水普遍存在的4种微藻:钝顶螺旋藻(Spirulina platensis)、铜绿微囊藻(Microcystis aeruginosa)、四尾栅藻(Scenedesmus quadricauda)和小球衣藻(Chlamydomonas microsphaera)作为试验材料,通过室内模拟实验,利用Langmuir、Freundlich和Dubinin-Radushkevich(D-R)3种等温吸附模型,研究4种活体微藻对Cd~(2+)的吸附规律及吸附参数。【结果】4种微藻对水体Cd~(2+)吸附均可以用Langmuir、Freundlich和D-R模型描述,其中用Langmuir模型拟合钝顶螺旋藻、Freundlich模型拟合小球衣藻、D-R模型拟合铜绿微囊藻和四尾栅藻的吸附效果最佳。四尾栅藻对Cd~(2+)的吸附量最高,而钝顶螺旋藻对Cd~(2+)的吸附量最低,但与Cd~(2+)的亲和力最强,4种微藻吸附Cd~(2+)主要是以离子代换为主的化学吸附。【结论】微藻对Cd~(2+)均有较强的吸附能力,会引起以微藻为食的水生动物Cd~(2+)富集;微藻也是去除水体Cd~(2+)的潜在吸附剂原料。