乙草胺在四种不同土壤中吸附行为研究

通过平衡振荡法测定了乙草胺在四种土壤中的吸附等温线,从影响因素、能量变化等方面研究了乙草胺在4种土壤中的吸附。结果表明:乙草胺易于被各种土壤吸附,土壤的吸附规律能够较好的符合Freundlich方程,拟合方程均有良好的线性关系。微生物的作用并没有显著改变乙草胺的吸附规律,乙草胺的吸附受到土壤有机质和矿物组成的显著影响。

Biosorption of Cd2+, Cu2+, Ni2+ and Zn2+ ions from aqueous solutions by pretreated biomass of brown algae

In this paper, marine brown algae Laminaria japonica was chemically modified by crosslinking with epichlorohydrin (EC1 and EC2), or oxidizing by potassium permanganate (PC), or crosslinking with glutaraldehyde (GA), or only washed by distilled water (DW). They were used for equilibrium sorption uptake studies with Cd2+, Cu2+, Ni2+ and Zn2+. The experimental data have been analyzed using Langmuir, Freundlich and Redlich-Peterson isotherms. The results showed that the biosorption equilibrium was well described by both the Langmuir and Redlich-Peterson isotherms.

Adsorption Behavior of Exogenous Thorium on Soil Contaminated by Rare Earth Industries

The adsorption behavior of exogenous thorium on soil was studied to evaluate the contaminated risk on soil. The adsorption capacity, equilibrium time, distribution coefficient and desorption ability were investigated by the experiments of static adsorption. The strong adsorption ability of exogenous thorium on soil samples was observed by high adsorption ratio (> 92%) and low desorption ratio (< 5%) in equilibrium, and the biggest distribution coefficient was over 10(4). The adsorption capacity and equilibrium time were related to soil properties. According to the results of adsorption, Freundlich equation (r >= 0.916 7) and Elovich equation (R-2 >= 0. 898 0) were primely fit for describing the thermodynamics and kinetics of the adsorption of exogenous thorium on soil samples, respectively, which indicated that the adsorption was belonged to the nonlinear adsorption, and was affected by the diffusion of thorium on soil surface and in mineral interbed. Sequential extraction procedure was employed to evaluate the bound fractions of exogenous thorium adsorbed on soil samples.

Adsorption of heavy rare earth(III) with extraction resin containing bis(2,4,4-trimethylpentyl) monothiophosphinic acid

In the present paper, the adsorption of thulium(Ill) from chloride medium on an extraction resin containing bis(2,4,4-trimethylpentyl) monothiophosphinic acid (CL302, HL) has been studied. The results show that 1.5 h is enough for the adsorption equilibrium. The distribution coefficients are determined as a function of the acidity of the aqueous phase and the data are analyzed both graphically and numerically. The plots of log D versus pH give a straight line with a slope of about 3, indicating that 3 protons are released in the adsorption reaction of thulium(III). The content of Cyanex302 in the resin is determined to be 48.21%. The total amount of Tm3+ adsorbed up to resin saturation is determined to be 82.46 mg Tm3+/g resin. Therefore, the sorption reactions of Tm3+ from chloride medium with CL302 can be described as: Tm3+ + 3HL((r)) <----> TmL3(r) + 3H(+) The Freundlich's isothermal adsorption equation is also determined as: log Q = 0.73 log C + 3.05 The amounts (Q) of Tm3+ adsorbed with the resin have been studied at different temperatures (15-40degreesC) at fixed concentrations of Tm3+, amounts of extraction resin, ion strength and acidities in the aqueous phase.

Adsorption studies of divalent metal ions with extraction resin containing 1-hexyl-4-ethyloctyl isopropylphosphonic acid

Equilibrium distributions of cobalt(II), nickel(II), zinc(II), cadmium(II), and copper(II) have been studied in the adsorption with extraction resin containing 1-hexyl-4-ethyloctyl isopropylphosphonic acid (HEOPPA) as an extractant from chloride medium. The distribution coefficients are determined as a function of pH. The data are analyzed both graphically and numerically. The extraction of the metal ions can be explained assuming the formation of metal complexes in the resin phase with a general composition ML2(HL)(q). The adsorbed species of the metal ions are proposed to be ML2 and the equilibrium constants are calculated. The efficiency of the resin in the separation of the metal ions is provided according to the separation factors values. The separation of Zn from Ni, Cd, Cu, Co, and Co from Ni, Cd, Cu with the resin is determined to be available. Furthermore, Freundlich's isothermal adsorption equations and thermodynamic quantities, i.e., DeltaG, DeltaH, and DeltaS are determined.

Co,Mo在Al_2O_3和K在Co-Mo催化剂上的吸附和分布

钴离子在γ-Al_2O_3上的吸附速度比钼酸根离子的慢,但钴离子的视扩散系数比钼酸根的大(25℃下D_(Co)=1.2×10~(-5)cm~2/s,D_(Mo)=4.4×10~(-6)cm~2/s)。钴的吸附等温线符合Langmuir等温式,而钼的符合Freundlich等温式。在等孔容积共浸法制备催化剂时,低pH值下由于Al_2O_3吸附Mo较多而导致Co、Mo在颗粒中分布不均;在高pH值下由于Mo的吸附量锐减,可用共浸法得到分布均匀的催化剂。K_2CO_3在均匀型Co-Mo/Al_2O_3催化剂上的吸附等温线符合Langmuir等温式,虽然吸附量较大,但在浸渍液中含量足够时也可得到均匀分布的结果。

海藻对水体中重金属的吸附研究

本文研究了三种大型藻及五种微藻的死藻体对水体中重金属离子的吸附。从藻细胞的形态学和光谱学以及咐附动力学和热力学等角度，探讨了海藻对金属离子的吸附机理。获得了吸附的适宜条件，为生物吸附剂在实际生产中的开发利用提供了生理基础。实验主要结果为：通过藻体死细胞与活细胞吸附研究比较，得出：藻体细胞的死亡不但不影响其吸附能力，而且可以解决用活体细胞作生物吸附剂进行工业废水处理的许多困难（如藻的营养问题、藻细胞对金属的耐受力等问题）。以死亡藻细胞作为生物吸附剂的细胞固定化技术有很大的工业应用前景。从藻细胞形态学和荧光发射光谱的研究得出，海藻对重金属的吸附不仅靠细胞壁成分对金属离子进行作用，细胞的内部物质也积极地参与吸附。吸附前后的细胞不仅表面强烈变形（变得凹凸不平），而且细胞的深层结构也发生了变化，使细胞的荧光发射光谱发生改变；未经吸附的藻细胞在紫光外激发下发出清晰的荧光，吸附之后荧光削弱甚至消失。吸附的热力学研究得出，吸附过程符合Freundlich吸附等温方程q = kc~b，可以认为该方程是少洋藻类－尤其是单胞藻吸咐金属的普遍模式。海藻对金属离子的吸附过程是多个一级反应并行的反应。藻体细胞存在着多个吸附官能团，这些官能团大致可以总括为快速吸附位点、中速吸附位点和慢速吸附位点三大类，实验模拟得出藻细胞吸附金属离子的动力学公式：C_e = Σ_(c_i) = C_(01)e~(-k1t) + C_(02)e~(-k2t) + C_(03)e~(-k3t)， 式中 k_1，k_2及k_3 代表三类吸附位点的反应速率常数。吸附的条件研究表明，吸附反应有一个最佳吸附温度和酸度，温度和酸度值过高或过低都不利于反应的进行；对于所实验的藻种，最佳吸附温度约为40 ℃，最佳吸附pH值在6.4左右。离子强度低利于吸附的进行。离子强度越高，藻对金属子的吸附量越低。当其它条件相同、离子强度由0.0016增至0.047，吸附容量减小了9倍。原因是各离子之间对吸附位点的竞争吸附，这种竞争关系决定了离子强度高时吸附空量较低。藻类对金属的吸附能力和金属离子的化学本质有密切的关系。各官能团对离子进行选择吸附，多种离子共存时，相互之间是竞争关系，这种竞争关系从侧面解释了低离子强度利于吸附进行的现象。各共存离子的吸附量及优先选择性主要决定于离子的软硬酸度。

藻体对水环境中N、P及重金属Cu2+、Pb2+、Cd2+、Cr6+的吸附特征研究

随着全球生态环境的恶化，各国日益重视对水体中各种污染物的治理。利用藻类的吸收、富集和降解作用，可以去除污水中的营养物质、重金属离子和有机污染物，与其他物理、化学及工程的方法相比，该技术具有以下优点：成本低、能耗小、治理效果较好，对环境污染小，有利于资源化，有利于整体生态环境的改善，是治理水质污染的新途径。 本文利用几种大型海藻对富营养化海水进行处理，结果发现孔石莼、刚毛藻均有很强的吸收N、P的能力，吸收能力依次为褶曲刚毛藻>束生刚毛藻>孔石莼。水体中褶曲刚毛藻3 g/L含量，在3～5小时之内，可把中等以上富营养化海水中的N、P降低至一类海水水平。利用刚毛藻处理富营养化地下海水和养殖废水，进行海参和大菱鲆养殖试验，探索藻类净化水质和废水循环利用的新模式，使水体保持较低的营养盐状态，减轻养殖废水对环境的影响，实现了海水养殖业与环境的可持续发展。 刚毛藻在我国近海滩涂分布广泛，利用它来处理富营养化水体，并和水产养殖业相结合，既净化水体，使养殖废水能循环利用，满足水产养殖的需求，又改善水产业生态环境。同时，将回收藻体生产优质饲料、食品和药物等，实现藻类资源的高值利用。刚毛藻营养丰富，用其替代鼠尾藻作海参饲料，资源丰富，成本低，效果好，是一种值得加以开发利用的宝贵资源，具有广泛的应用前景。 生物吸附法是一种经济有效的移除废水中有害重金属离子的方法。由于藻类细胞壁中的多聚糖可提供吸附重金属的位点，廉价而蕴藏丰富的海藻对多种重金属表现出很强的吸附能力。所以本文通过分批实验，研究了非活体刚毛藻对水体中重金属Cu2+、Pb2+和Cd2+的吸附影响因子、吸附热力学、吸附动力学及吸附机理，得到了平衡等温线及动力学数据。吸附过程的最佳pH值为5.0，吸附量随温度的升高而增加，水体中常见的Na+、K+、Ca2+、Mg2+阳离子及Cl-、NO3-、SO42-、C2O42-等阴离子的存在对吸附的影响并不显著。EDTA存在时，吸附百分率大大降低。吸附等温线符合Langmuir和Freundlich方程。刚毛藻对重金属Cu2+、Pb2+和Cd2+的吸附容量很高，25℃时，对Cu2+、Pb2+和Cd2+的最大吸附容量分别为1.61 mmol/g、0.96 mmol/g和0.98 mmol/g，且吸附过程为吸热反应。刚毛藻对重金属Cu2+、Pb2+和Cd2+的吸附过程为化学吸附，在吸附过程中藻体表面的官能团可能与金属离子发生了螯合作用。吸附动力学过程符合pseudo-二级动力学模型，在初始的30min内，吸附速率很快，随后速率逐渐降低。解吸试验表明，用EDTA可以对重金属进行回收，刚毛藻可以循环利用。实验结果表明刚毛藻是一种高效、经济实用的生物吸附材料，可用来吸附回收水体中的重金属Cu2+、Pb2+和Cd2+等。 通过非活体刚毛藻对重金属Cr6+的吸附影响因子、吸附动力学、吸附机理的研究发现，刚毛藻对Cr6+具有很强的还原能力，对电镀废水中的Cr6+的还原去除提供了非常好的方法。吸附过程的最佳pH值为2～3，实际电镀废水通常在此pH范围，因此处理实际废水时，首先在原酸性条件下，对Cr6+进行还原去除，然后调废水pH至5.0，继续进行吸附，去除其他二价离子及被还原的三价Cr离子，实现了利用同一材料还原Cr6+为Cr3+，并将Cr3+和其他重金属离子同时去除。通过对机理的讨论，认为刚毛藻对Cr6+的生物吸附过程不是一个简单的“离子交换过程”，而是一个“吸附还原过程”。在海藻量足够的前提下，只要时间足够长，Cr6+可被彻底还原去除。 利用工业废弃物褐藻渣，对水体中重金属离子Cu2+、Pb2+、Cd2+及Cr6+的生物吸附特性分别进行了讨论，结果表明褐藻渣对重金属离子的吸附特性与刚毛藻一致，吸附等温线符合Langmuir和Freundlich方程，在25℃时，pH为5.0时，由Langmuir方程求出褐藻渣对Cu2+、Pb2+和Cd2+的最大吸附容量分别为4.20 mmol/g、3.13 mmol/g和2.97 mmol/g。褐藻渣对低、高浓度的重金属Cr6+都具有很强的吸附能力，且移除效果比较彻底。实际应用结果表明，褐藻渣是一种高效、经济实用的生物吸附材料，可用来吸附回收水体中的重金属离子，具有广泛的应用前景。

Sorption and desorption of Cu and Cd by macroalgae and microalgae

The sorption and desorption of Cu and Cd by two species of brown macroalgae and five species of microalgae were studied. The two brown macroalgae, Laminaria japonica and Sargassum kjellmanianum, were found to have high capacities at pHs between 4.0 and 5.0 while for microalgae, optimum pH lay at 6.7. The presence of other cations in solution was found to reduce the sorption of the target cation, suggesting a competition for sorption sites on organisms. Sorption isotherms obeyed the Freundlich equation, suggesting involvement of a multiplicity of mechanisms and sorption sites. For the microalgae tested, Spirulina platensis had the highest capacity for Cd, followed by Nannochloropsis oculata, Phaeodactylum tricornutum, Platymonas cordifolia and Chaetoceros minutissimus. The reversibility of metal sorption by macroalgae was examined and the results show that both HCl and EDTA solutions were very effective in desorbing sorbed metal ions from macroalgae, with up to 99.5% of metals being recovered. The regenerated biomass showed undiminished sorption performance for the two metals studied, suggesting the potential of such material for use in water and wastewater treatment. (C) 1998 Elsevier Science Ltd. All rights reserved.

Sorption and desorption of lead (II) from wastewater by green algae Cladophora fascicularis

Biosorption is an effective method to remove heavy metals from wastewater. In this work, adsorption features of Cladophora fascicularis were investigated as a function of time, initial pH, initial Pb(II) concentrations, temperature and co-existing ions. Kinetics and equilibria were obtained from batch experiments. The biosorption kinetics followed the pseudo-second order model. Adsorption equilibria were well described by the Langmuir and Freundlich isotherm models. The maximum adsorption capacity was 198.5 mg/g at 298 K and pH 5.0. The adsorption processes were endothermic and the biosorption heat was 29.6 kJ/mol. Desorption experiments indicated that 0.01 mol/L Na(2)EDTA was an efficient desorbent for the recovery of Pb(II) from biomass. IR spectrum analysis suggested amido or hydroxy, C=O and C-O could combine intensively with Pb(II). (C) 2006 Elsevier B.V. All rights reserved.

Biosorption of copper (II) and lead (II) from aqueous solutions by nonliving green algae Cladophora fascicularis: Equilibrium, kinetics and environmental effects

Biosorption of Cu2+ and Pb2+ by Cladophora fascicularis was investigated as a function of initial pH, initial heavy metal concentrations, temperature and other co-existing ions. Adsorption equilibriums were well described by Langmuir and Freundlich isotherm models. The maximum adsorption capacities were 1.61 mmol/ g for Cu2+ and 0.96 mmol/ g for Pb2+ at 298K and pH 5.0. The adsorption processes were endothermic and biosorption heats calculated by the Langmuir constant b were 39.0 and 29.6 kJ/ mol for Cu2+ and Pb2+, respectively. The biosorption kinetics followed the pseudo- second order model. No significant effect on the uptake of Cu2+ and Pb2+ by co-existing cations and anions was observed, except EDTA. Desorption experiments indicated that Na(2)EDTA was an efficient desorbent for the recovery of Cu2+ and Pb2+ from biomass. The results showed that Cladophora fascicularis was an effective and economical biosorbent material for the removal and recovery of heavy metal ions from wastewater.

硫酸盐还原菌混合菌群胞外聚合物对Cu^2＋的吸附和机理

生物吸附法是处理含重金属废水的一种新兴的处理技术。微生物所分泌的胞外聚合物（EPS）在微生物吸附重金属中起重要作用。硫酸盐还原菌（SRB）混合菌群分泌的EPS能有效的吸附水溶液中的Cu^2＋，Langmuir等温方程和Freundlich等温方程都能拟合实验所得吸附数据，最大吸附容量达到478．47mg／gEPS。水溶液的初始pH值对EPS吸附Cu^2＋影响明显，在pH为7时，吸附效率最高，pH增减，吸附效率明显下降。SRB混合茵群分泌的EPS的FT—IR分析表明，EPS对Cu^2＋的吸附主要在于EPS中的蛋白质的酰胺（Ⅱ）、羧基、多聚糖的C-O-C、OH和脂类等基团对Cu^2＋的强络合能力.

硫酸盐还原菌混合菌群胞外聚合物对Zn^2＋的吸附和机理

硫酸盐还原菌（SRB）混合菌群分泌的胞外聚合物（EPS）能有效地吸附水溶液中的Zn^2＋在初始p（Zn^2＋）为500mg/L时，EPS对Zn^2＋的吸附量达到326．07mg/g，g。Freundlich方程能相对较好地拟合实验所得吸附数据。SRB混合菌群分泌的EPS的IR分析表明，EPS吸附Zn^2＋起主要作用的官能团是多聚糖C-O-C，羧基和脂类官能团，而蛋白质和多聚糖的-OH对Zn^2＋的结合能力有限.

1，3，5-三氯苯在土壤沉积物水体系中的吸附过程研究

以自然土壤、沉积物样品为研究对象，研究了1，3，5-三氯苯在样品上的等温吸附过程。结果表明，线性模型和Freundlich模型能较好地拟合所有样品的等温线，而双区位反应模型(DRDM)适用范围有限。研究表明，三氯苯的吸附容量大小主要取决于样品中有机碳的含量，并且与不可提取态有机质和粘土矿物含量有一定的关系。以自然土壤、沉积物样品为研究对象，研究了1，3，5-三氯苯在样品上的等温吸附过程。结果表明，线性模型和Freundlich模型能较好地拟合所有样品的等温线，而双区位反应模型(DRDM)适用范围有限。研究表明，三氯苯的吸附容量大小主要取决于样品中有机碳的含量，并且与不可提取态有机质和粘土矿物含量有一定的关系。

菲在土壤／沉积物上的吸附-解吸过程及滞后现象的研究

实验研究了菲在土壤／沉积物上的吸附一解吸过程。CHL土壤和HFH沉积物中有机质的固相^13C CP MAS NMR谱图很相似，表明样品中有机质的组成差异不大；菲在土壤／沉积物上的吸附过程表现出明显的非线性；线性模型不适合拟合菲的吸附等温线，Freundlich模型和双区位反应模型(DRDM)较好地拟合了菲的吸附等温线，其中DRDM模型还清楚地反映菲在低浓度和高浓度下不同的吸附方式；另外，研究表明菲在土壤／沉积物上的解吸过程中存在明显的滞后现象，这可能和土壤／沉积物有机质的异质性和土壤胶团微小孔隙的存在有关。实验研究了菲在土壤／沉积物上的吸附一解吸过程。CHL土壤和HFH沉积物中有机质的固相^13C CP MAS NMR谱图很相似，表明样品中有机质的组成差异不大；菲在土壤／沉积物上的吸附过程表现出明显的非线性；线性模型不适合拟合菲的吸附等温线，Freundlich模型和双区位反应模型(DRDM)较好地拟合了菲的吸附等温线，其中DRDM模型还清楚地反映菲在低浓度和高浓度下不同的吸附方式；另外，研究表明菲在土壤／沉积物上的解吸过程中存在明显的滞后现象，这可能和土壤／沉积物有机质的异质性和土壤胶团微小孔隙的存在有关。