不同水体生物膜中各化学组分对铅的吸附作用研究

水中的底泥、悬浮物和生物膜等固相物质对重金属在水中的迁移和转化有重要影响 [1,2 ] ,而固相物质中起主要作用的是吸附能力强的铁、锰氧化物和有机质 [3,4 ] .对生物膜与重金属相互作用的研究已经有报道 [5,6] .Nelson等[3] 用吸附加和模型模拟生物膜上各组分对铅吸附 ;Dong等 [7] 用选择性萃取的方法研究生物膜各组分对铅、镉的吸附情况 ,但他们的研究均局限于单一水体 ,本文采用萃取 -吸附-统计分析的方法研究多个自然水体生物膜中铁、锰氧化物和有机质对铅吸附的相对贡献 .1　实验部分1 .1　生物膜的培养及组分测定　选吉林省境内的净…     

采集的生物膜中痕量重金属的形态分布特征

采用改进的Tessier连续萃取方法对从松花江中采集的生物膜中锰、 铁、 铜、 铅、 锌及镉的化学形态进行分析, 考察了生物膜上铁、 锰氧化物和有机质吸附重金属的相对作用, 同时讨论了在研究培养的生物膜吸附痕量重金属时所建立的选择性萃取方法对于采集的生物膜组分分离的适用性.  研究结果表明, 在采集的生物膜上痕量重金属以铁、 锰的氧化物为主要结合形态存在, 以此种形态存在的铜、 锌、 铅和镉分别占其总含量的62.9%， 58.3%， 53.8%和32.6%, 而以有机结合态存在的铜、 锌、 铅和镉, 分别占其总含量的1.1%， 0.6%， 9.9%和1.8%, 表明采集的生物膜上铁、 锰氧化物在吸附重金属的过程中起主要的控制作用, 而有机质的作用相对较小, 与以往利用选择性萃取技术研究培养的生物膜吸附重金属的规律一致.  进一步分析表明, 如扣除生物膜上铁的残渣态部分, 则选择性萃取分离技术可以有效地将采集的生物膜上的铁、 锰氧化物及有机质分离开.      

自然水体生物膜吸附Co,Ni和Cu的特征研究

研究了在自然水体中培养的生物膜吸附Co,Ni和Cu等3种重金属的热力学和动力学特征,并对生物膜吸附各重金属的热力学数据进行了非线性拟合.结果表明,3种重金属的吸附过程均符合Langmuir吸附等温曲线.在溶液中重金属浓度<0.5μmol/L时,生物膜对3种重金属元素的吸附能力顺序是Co>Cu>Ni;在重金属浓度>0.5μmol/L时,顺序是Cu>Co>Ni.对动力学数据进行非线性拟合的结果表明,生物膜对Co,Ni和Cu的吸附均在数小时内达到平衡,吸附过程符合Langmuir等动力学曲线.     

自然水体中生物膜不同化学组分与铅、镉最大吸附量的关系

生物膜存在于河流、湖泊和湿地环境中岩石和表层沉积物表面上 ,并由地球上不同种类的微生物组成 [1,2 ] .大量证据表明 ,生物膜在决定水环境中痕量金属的迁移、最终归宿、生物地球化学特性、生物可利用性和毒性过程中起着非常重要的作用 .因此 ,研究生物膜对痕量金属的吸附、预测重金属在水环境中的迁移转化规律具有重要的理论意义 .从环境化学角度看 ,生物膜上的主要成分铁氧化物、锰氧化物和有机质一直被认为是影响痕量金属在固体表面吸附的 3个最重要的因素[3] .有的文献认为 ,金属氧化物是痕量金属吸附唯一最重要的决定因素 [4 ,5] ,有…     

表层沉积物(生物膜)非残渣态组分的选择性萃取分离及其吸附铜/锌的特性

采用化学萃取技术对表层沉积物(生物膜)的非残渣态组分(铁、锰氧化物及有机质)进行了分离, 并研究了表层沉积物(生物膜)非残渣态和残渣态组分吸附铜、锌的特性. 结果表明, 0.1 mol/L NH2OH·HCl+0.1 mol/L HNO3, (NH4)2C2O4-H2C2O4缓冲溶液和体积分数为30%的H2O2可选择性地萃取分离表层沉积物(生物膜)非残渣态的锰氧化物、铁锰氧化物和有机质, 萃取率为63.15%～97.59%, 同时对非目的组分影响较小; 表层沉积物(生物膜)及其各组分对铜的吸附能力均大于对锌的吸附能力, 且生物膜及其各组分对铜、锌的吸附能力均高于表层沉积物及其相应组分对铜、锌的吸附能力; 表层沉积物(生物膜)非残渣态组分对铜、锌的吸附能力均大于残渣态组分, 且非残渣态组分中锰氧化物的单位吸附能力最强, 其次是铁氧化物, 而有机质的单位吸附能力较弱, 比锰氧化物低2个数量级, 说明生物膜对水体中痕量重金属的迁移转化作用强于表层沉积物, 而表层沉积物(生物膜)中金属(铁、锰)氧化物对水中痕量重金属起主要控制作用.     

聚丙烯酸对自然水体生物膜吸附镉的影响

选择聚丙烯酸(PAA)为水中溶解态高分子天然有机质的代表, 研究了PAA对自然水体生物膜吸附重金属Cd的影响, 包括不同浓度的PAA对吸附的影响, PAA对特定pH下吸附等温线的影响以及不同pH下按不同顺序添加PAA时对吸附的影响. 研究结果表明, PAA的存在一般会降低生物膜对Cd的吸附, 其影响程度与PAA的浓度、 溶液pH、 吸附顺序及生物膜厚度等有关. PAA与Cd的浓度比越高, 其对吸附的影响越显著. 吸附溶液pH越高, PAA的影响越显著. 吸附顺序对吸附的影响在pH较低时不明显, 当pH较高时, 先加PAA后加Cd及两者同时吸附时对吸附的降低作用接近且较大, 先加Cd后加PAA时对吸附的降低作用相对较小. 生物膜较薄时PAA的影响更显著. PAA对生物膜吸附Cd的影响主要由PAA与生物膜之间对Cd的竞争以及三元表面配合物的生成与吸附2种因素共同决定. 高pH会促进PAA与Cd的配合而不利于带负电的配合物在生物膜上的吸附.     

湖水中的颗粒物对水体生物膜吸附铅、镉的影响

采用逐级过滤的方式对湖水进行过滤,并用含有不同粒径颗粒物的湖水进行生物膜的培养,以研究水中颗粒物对生物膜吸附痕量重金属的影响.研究结果表明,生物膜上铁、锰氧化物含量与水中总铁、总锰含量呈明显的线性关系,锰氧化物的含量受水中颗粒物粒径分布的影响很大.生物膜吸附铅、镉的热力学过程符合Langmuir方程,且膜上铁、锰氧化物吸附铅、镉的能力随着湖水中颗粒物粒径的减小呈增强的趋势.     

自然水体生物膜胞外蛋白质吸附铅和镉的研究

本文通过长春市南湖水中生物膜优势菌种胞外蛋白吸附Pb2+和Cd2+的实验, 研究了胞外蛋白吸附重金属的规律.     

硅胶自溶液中吸附胆固醇和卵磷脂

卵磷脂和胆固醇是细胞膜的主要组成,它们在不同界面上的定向排列方式对细胞膜的结构与功能起着重要的作用。用固体物质自非水溶剂中吸附类脂化合物形成类脂单层,再自水溶液中吸附蛋白质,可制成固体载体上的模拟生物膜。在固体表面上的类脂单层膜中类     

铁、锰氧化物在自然水体生物膜上的分布

在自然水体中 ,生物膜是一个开放的动力学系统 ,生物膜的形成及其组分处于动态的变化中——水环境中的各种成分在生物膜上发生着合成、聚结、转化、降解等作用 ,从而成为生物膜的一部分 ,还会随着生物膜的脱落重新进入水相中 ,所有这些变化 ,与生物膜本身的性质是分不开的 [1～ 3] 。从环境化学角度看 ,自然水体中生物膜主要化学组分包括金属氧化物 (铁氧化物、锰氧化物和铝氧化物等 )、有机质及少量的矿物质 ,其中 ,铁、锰氧化物在影响痕量重金属在水环境中的迁移、最终归宿、生物地球化学特性、生物可利用性和毒性过程中起着非常重要的作…     

Biosorption of copper(II) and zinc(II) from aqueous solution by Pseudomonas putida CZ1

To study Pseudomonas putida CZ1, having high tolerance to copper and zinc on the removal of toxic metals from aqueous solutions, the biosorption of Cu(II) and Zn(II) by living and nonliving P. putida CZ1 were studied as functions of reaction time, initial pH of the solution and metal concentration. It was found that the optimum pH for Zn(II) removal by living and nonliving cells was 5.0, while it was 5.0 and 4.5, respectively, for Cu(II) removal. At the optimal conditions, metal ion biosorption was increased as the initial metal concentration increased. The adsorption data with respect to both metals provide an excellent fit to the Langmuir isotherm. The binding capacity of living cells is significantly higher than that of nonliving cells at tested conditions. It demonstrated that about 40-50% of the metals were actively taken up by P. putida CZ1, with the remainder being passively bound to the bacterium. Moreover, desorption efficiency of Cu(II) and Zn(II) by living cells was 72.5 and 45.6% under 0.1M HCl and it was 95.3 and 83.8% by nonliving cells, respectively. It may be due to Cu(II) and Zn(II) uptake by the living cells enhanced by intracellular accumulation.     

Heavy-metal extraction capability of chalcogenoic aminophosphines derived from 1-amino-4-methylpiperazine

Aminophosphine of the type (Ph₂PNHR) derived from 1-amino-4-methylpiperazine and its chalcogen derivatives (Ph₂P(X)NHR X = S, Se) were used as ligands in solvent extraction of metal picrates such as Cu²⁺, Ni²⁺, and Pb²⁺ from the aqueous to the organic phase. Influence of parameters such as pH of the aqueous phase, ligand concentration in the organic phase, and concentration of the extractant extracted from the aqueous to the organic phase was investigated to determine the ligands’ ability to extract metal ions. Metal picrate extraction was investigated at 25°C using UV-VIS spectrophotometry in dichloromethane in the absence and in the presence of Ph₂PNHR and chalcogenides. The extraction results revealed that the extraction percentage of Cu²⁺, Ni²⁺, and Pb²⁺ metals was much higher at lower pH values, indicating an acidity dependent complexation equilibrium.     

Biosorption of Pb(II) and Cd(II) ions by Agave sisalana (sisal fiber)

The present work proposes the use of Agave sisalana (sisal fiber) as an natural adsorbent for ions Pb(II) and Cd(II) biosorption from natural waters. The flame atomic absorption spectrometry was used for quantitative determination and study of the ions Pb(II) and Cd(II) adsorption on the solid phase. The Fourier transform infrared spectroscopy (FT IR) was used to investigate the sisal structure and the specific BET surface area was analyzed. The biosorption potential of sisal as biosorbent for the removal of the ions Pb(II) and Cd(II) from aqueous solution was investigate considering the followings parameters: pH, biomass amount and contact time. Langmuir and Freundlich isotherms were used to evaluate adsorption behavior of the ions on this solid phase. The results showed that sisal has a surface area to adsorption of 0.0233 m² g^{− 1}, and the OH and CO functional groups are the main involved in the biosorption. The best interpretation for the experimental data was given by Freundlich isotherm that proposes a monolayer sorption with a heterogeneous energetic distribution of active sites, accompanied by interactions between sorbed molecules. The maximum monolayer biosorption capacity was found to be 1.85 mg g^{− 1} for Cd (II) and 1.34 mg g^{− 1} for Pb (II) at pH 7 and 296 K. This phase solid can be used for biosorption of cadmium and lead in polluted natural waters.     

Preparation of silica-supported porous sorbent for heavy metal ions removal in wastewater treatment by organic-inorganic hybridization combined with sucrose and polyethylene glycol imprinting

A new porous sorbent for wastewater treatment of metal ions was synthesized by covalent grafting of molecularly imprinted organic-inorganic hybrid on silica gel. With sucrose and polyethylene glycol 4000 (PEG 4000) being synergic imprinting molecules, covalent surface coating on silica gel was achieved by using polysaccharide-incorporated sol-gel process starting from the functional biopolymer, chitosan and an inorganic epoxy-precursor, gamma-glycidoxypropyltrimethoxysiloxane (GPTMS) at room temperature. The prepared porous sorbent was characterized by using simultaneous thermogravimetry and differential scanning calorimeter (TG/DSC), scanning electron microscopy (SEM), nitrogen adsorption porosimetry measurement and X-ray diffraction (XRD). Copper ion, Cu²⁺, was chosen as the model metal ion to evaluate the effectiveness of the new biosorbent in wastewater treatment. The influence of epoxy-siloxane dose, buffer pH and co-existed ions on Cu²⁺ adsorption was assessed through batch experiments. The imprinted composite sorbent offered a fast kinetics for the adsorption of Cu²⁺. The uptake capacity of the sorbent imprinted by two pore-building components was higher than those imprinted with only a single component. The dynamic adsorption in column underwent a good elimination of Cu²⁺ in treating electric plating wastewater. The prepared composite sorbent exhibited high reusability. Easy preparation of the described porous composite sorbent, absence of organic solvents, cost-effectiveness and high stability make this approach attractive in biosorption.     

Removal and recovery of copper (II) ions by bacterial biosorption

Studies were conducted toinvestigate the removal and recovery of copper (II) ions from aqueous solutions by Micrococcus sp., which was isolated from a local activated sludge process. The equilibrium of copper biosorption followed the Langmuir isotherm model very well with a maximum biosorption capacity (q_max) of 36.5 mg of Cu²⁺/gofdry cell at pH 5.0 and 52.1 mg of Cu²⁺/g of dry cell at pH 6.0. Cells harvested at exponential growth phase and stationary phase showed similar biosorption characteristics for copper, Copper uptake by cells was negligible at pH 2.0 and then increased rapidly with increasing pH un til 6.0. In multim etal systems, Micrococcus sp. exhibited a preferential biosorption order: Cu−Pb>Ni−Zn. There is virtually no interference with copper uptake by Micrococcus sp. from solutions bearing high concentrations of Cl⁻, SO ₄ ²⁻ , and NO3/− (0–500 mg/L). Sulfuric acid (0.05 M) was the most efficient desorption medium, recovering >90% of the initial copper sorbed. The copper capacity of Micrococcus sp. remained unchanged after five successive sorption and desorption cycles. Immobilization of Micrococcus sp. in 2% calcium alginate and 10% polyacrylamide gel beads increased copper uptake by 61%. Biomass of Micrococcus sp. may be applicable to the development of potentially cost-effective biosorbent for removing and recovering copper from effluents.     

Biosorption of copper(II) and cadmium(II) by a novel exopolysaccharide secreted from deep-sea mesophilic bacterium

The biosorption behaviors and mechanisms of a novel exopolysaccharide (EPS), which is secreted by a mesophilic bacterium (namely Wangia profunda (SM-A87)) isolated from deep-sea sediment, for heavy metals Cu(II) and Cd(II) have been studied in this paper. The effects of SM-A87 EPS concentration, solution pH and ionic strength on the metal uptake were investigated by employing batch adsorption techniques, respectively. The optimum biosorption capacities were observed at pH 5.0 for Cu(II) with 48.0 mg/g and pH 6.0 for Cd(II) with 39.75 mg/g, respectively. Addition of salts decreased Cu(II) or Cd(II) uptake in the order of K⁺ < Na⁺ < Ca²⁺. Langmuir and Freundlich models were employed to describe the biosorption equilibrium data, indicating the favorable biosorption occurs and larger biosorption capacity and intensity for Cu(II) than for Cd(II). The biosorption kinetics for both metals can be well described by pseudo-second-order kinetic model, compared with pseudo-first-order and intraparticle diffusion kinetic models. The competitive biosorption was also studied, indicating that in two-component solution with different metal ratios, the selective biosorption of SM-A87 EPS for Cu(II) was much higher than for Cd(II). The Fourier transform infrared spectroscopy (FT-IR) analysis indicated possible functional groups (e.g., OH, COO and COC) of SM-A87 EPS involved in metal biosorption process, which indicated the potential of using SM-A87 EPS as an effective sorbent for Cu(II) or Cd(II) removal from water.     

Removal of Th(IV) ions from aqueous solution using bi-functionalized algae-yeast biosorbent

Composites could be more effective adsorbents than inorganic and organic components individually. In the present study, the red macro marine algae, Jania Rubens and yeast, Saccharomyces cerevisiae immobilized on silica gel were used as a constituent of bi-functionalized biosorbent to remove thorium ions from aqueous solution. Optimum biosorption conditions were determined as a function of pH, initial Th(IV) concentration, contact time, temperature, volume/mass ratio and co-ion effect. The morphological analysis of the biocomposite was performed by the scanning electron microscopy and functional groups in the biosorbent were determined by FT-IR spectroscopy. In order to find the adsorption characteristics, Langmuir, Freundlich, and Dubinin–Radushkevich adsorption isotherms were applied to the adsorption data. The data were well described by Langmuir adsorption isotherms while the fit of Freundlich adsorption isotherms and Dubinin–Radushkevich equation to adsorption data was poor. Using the equilibrium constant value obtained at different temperature, the thermodynamics properties of the biosorption (ΔG°, ΔH° and ΔS°) were also determined. The results show that biosorption of Th(IV) ions onto biocomposite was exothermic nature, spontaneous and more favorable at lower temperature under examined conditions.     

Biosorption of Heavy Metal Ions (Cu2+, Mn2+, Zn2+, and Fe3+) from Aqueous Solutions Using Activated Sludge: Comparison of Aerobic Activated Sludge with Anaerobic Activated Sludge

The potential of using two different kinds of air drying of activated sludge (aerobic activated sludge and anaerobic activated sludge) for the removal of Cu²⁺, Mn²⁺, Zn²⁺, and Fe³⁺ from aqueous solutions was assessed. Results indicated that the maximum biosorption occurred at pH?=?5.0 for Cu²⁺, Zn²⁺, and Mn²⁺ and pH?=?3.0 for Fe³⁺. The kinetic parameters of biosorption data were found to be best fitted to the second-order equation. Also, it was found that the best dosage for biosorption was 0.2?g for both aerobic activated sludge and anaerobic activated sludge. The experimental results were fitted well to the Langmuir, Freundlich, and Dubinin?CRadushkevich (D-R) isotherms. The maximum biosorption capacities of Cu²⁺, Mn²⁺, Zn²⁺, and Fe³⁺ for aerobic activated sludge were 65.789, 44.843, 64.935, and 75.756?mg/g, respectively, while they were 59.880, 49.020, 62.500, and 69.444?mg/g for anaerobic activated sludge, respectively. The mean free energy values evaluated from the D-R model indicated that the biosorptions of studied heavy metal ions onto activated sludge were taken place by chemical interaction. The results of this study provided valuable information on the biosorption of heavy metals by activated sludge that may contribute in wastewater treatment.