Utilization of Modified Attapulgite for the Removal of Sr(II), Co(II), and Ni(II) Ions from Multicomponent System,Part I: Kinetic Studies

Radionuclide sorption by natural and modified clays is extensively accepted to be an important process from the radioactive waste point of view. This work focused on modification of natural attapulgite with a layered double hydroxide to produce a novel chemisorbent for Sr2+, Ni2+, and Co2+ removal from multicomponent solution. The structural and surface characteristics of both attapulgite (ATP) and modified attapulgite (LDH-ATP) were investigated using XRD, FTIR, SEM, and thermal analysis. Comparison of sorption features of Sr2+, Ni2+, and Co2+ onto ATP and LDH-ATP was achieved; the results indicated that LDH-ATP was the most efficient sorbent for Sr2+, Ni2+, and Co2+. Kinetic studies established that the sorption is fast and reaching >90% within 30 min. The sorption of Sr2+, Ni2+, and Co2+ are well defined by non-linear pseudo-second-order model and controlled by an intra-particle diffusion mechanism. The diffusivity was determined using homogeneous surface diffusion (HSDM) model and found in the order 10−13 m2/min; this confirmed that the sorption of the three ions is chemisorption process. LDH-ATP can be employed as a candidate chemisorbent for the removal of some metal ions from waste solution.     

Adsorption mechanism of Zn2+, Ni2+, Cd2+, and Cu2+ ions by carbon-based adsorbents: interpretation of the adsorption isotherms via physical modelling

Environmental Science and Pollution Research - A theoretical physicochemical and thermodynamic investigation of the adsorption of heavy metals Zn2+, Cd2+, Ni2+, and Cu2+on carbon-based adsorbents...     

Evaluation of pectin binding of heavy metal ions in aqueous solutions

Evaluation of adsorption performance of several industrially manufactured pectins towards some toxic heavy metals was carried out. Adsorption isotherms for divalent cations in simulant aqueous solutions were measured and corresponding distribution coefficients were calculated. The following selectivity sequences we found for pectins: Pb2+ > Cu2+ > Co2+ > Ni2+ > Zn2+ > Cd2+. It was shown that a beet pectin exhibits a high affinity for Pb2+ and Cu2+ ions, an apple pectin for Co2+ ion and a citrus pectin for Ni2+ ion. The binding properties of all pectins towards Zn2+ and Cd2+ ions are extremely poor. The quantitative data on adsorption performance of pectins suggest their applicability as food additives or remedies for efficient removal of Pb2+, Cu2+, Co2+, and Ni2+ ions from different biological systems, including human and animal organisms.     

Predictions of binary sorption isotherms for the sorption of heavy metals by pine bark using single isotherm data

The adsorption of three heavy metal ions by pine bark was studied. The study was divided into two parts; single component adsorption of the metals Cu2+, Cd2+ and Ni2+ and bisolute adsorption of the three binary systems Cu2+-Cd2+, Cu2+-Ni2+ and Cd2+-Ni2+. Extended Langmuir model, extended Freundlich model. Sips model and ideal adsorption solution theory (IAST) models were used to predict the equilibrium uptake for Cu2+, Cd2+ and Ni2+ in the binary diluted solutions using the single adsorption constants. The experimental data of single isotherm adsorption process were found to follow Langmuir isotherm model with less accuracy than Freundlich and Sips models. Whereas, the predictions of bisolute adsorption isotherms of the mentioned three systems, Cu2+-Cd2+, Cu2+-Ni2+ and Cd2+-Ni2+, showed good agreement with experimental data when using Extended-Langmuir, Extended-Freundlich and IAST. However, the only good fit of the Sips model was with the Cu2+-Cd2+ system.     

季铵化合物对好氧活性污泥吸附Ni2+的影响研究

以季铵化合物中最具潜在影响力、毒性较大的苄基季铵盐(BAC)为模型物,进行了BAC对好氧活性污泥吸附Ni2+的影响研究.结果表明,当反应液初始pH≤3时,不同浓度的BAC对好氧活性污泥吸附Ni2+的影响较小,当初始pH在3～9时,不同浓度的BAC对Ni2+吸附的抑制影响顺序为100 mg/L＞20 mg/L＞0 mg/...     

交联壳聚糖对重金属离子的吸附性能研究

以海蟹壳为原料制备的壳聚糖在碱性条件下,经环氧氯丙烷交联制得水不溶性的交联壳聚糖,采用静态法研究交联壳聚糖对Ｃｕ＾２＋,Ｃｒ＾３＋,Ｎｉ＾２＋,Ｐｂ＾２＋,Ｚｎ＾２＋,Ｈｇ＾２＋等几种重金属离子的吸附性能及ｐＨ值对吸附性能的影响,探讨了它们的作用机理。     

皂化改性橘子皮生物吸附剂对重金属离子的吸附

以生物废料橘子皮(OP)为原料,经乙醇、氢氧化钠处理,得到改性橘子皮生物吸附剂SOP,将其用于对重金属离子Cu2+、Pb2+、Cd2+、Zn2+和Ni2+的吸附。研究了溶液pH、吸附时间和重金属离子初始浓度对SOP吸附性能的影响。结果表明,重金属离子在生物吸附剂上的吸附速率快,符合准二级动力学方程。SOP对重金属离子的吸附等温线符合Lang-muir模型,根据Langmuir模型计算SOP对Cu2+、Pb2+、Cd2+、Zn2+和Ni2+的饱和吸附量分别为56.82、152.4、66.27、33.90和23.02 mg/g,均高于改性前。常见阳离子的存在对重金属离子吸附的影响较小,改性后的橘子皮生物吸附剂可以再生重复使用4次以上,是性能良好的重金属离子吸附剂。     

Simultaneous heavy metal removal mechanism by dead macrophytes

The use of dead, dried aquatic plants, for water removal of metals derived from industrial activities as a simple biosorbent material has been increasing in the last years. The mechanism of simultaneous metal removal (Cd2+, Ni2+, Cu2+, Zn2+ and Pb2+) by 3 macrophytes biomass (Spirodela intermedia, Lemna minor and Pistia stratiotes) was investigated. L. minor biomass presented the highest mean removal percentage and P. stratiotes the lowest for all metals tested. Pb2+ and Cd2+ were more efficiently removed by the three of them. The simultaneous metal sorption data were analysed according to Langmuir and Freundlich isotherms. Data fitted the Langmuir model only for Ni and Cd, but Freundlich isotherm for all metals tested, as it was expected. The K(F) values showed that Pb was the metal more efficiently removed from water solution. The adsorption process for the three species studied followed first order kinetics. The mechanism involved in biosorption resulted ion exchange between monovalent metals as counter ions present in the macrophytes biomass and heavy metal ions and protons taken up from water. No significant differences were observed in the metal exchange amounts while using multi-metal or individual metal solutions.     

天然及CaCl2改性沸石对四环素的吸附

通过静态吸附实验研究了水中四环素在天然和CaCl2改性沸石上的吸附行为及机制。实验表明,天然沸石对四环素具有吸附能力,CaCl2改性可以提高沸石对四环素的吸附能力。天然和改性沸石对四环素的吸附符合拟二级动力学模型,颗粒内扩散不是吸附过程的主要控制步骤。Freundlich和Dubinin-Radushkevich(D-R)等温吸附模型可以较好地描述实验所用2种沸石对四环素的吸附行为,D-R等温方程拟合结果显示吸附过程包含离子交换作用。通过对天然和改性沸石吸附四环素前后溶液中主要阳离子浓度变化分析证实了该吸附过程包含离子交换作用。实验研究了pH值变化对沸石吸附四环素的影响,当pH=3～5时,天然和改性沸石对四环素的吸附量均随pH值的增加而急剧下降,而pH=5～10时,天然和改性沸石对四环素的吸附量变化均不明显,推测可能是离子交换作用和化学沉淀吸附作用所致。另外,实验还初步探索了溶液离子强度对沸石吸附四环素的影响情况,随着溶液中Na+和Ca2+离子强度的增加,吸附量先急剧降低随后趋向平稳,进一步说明了沸石对四环素的吸附过程不是由单一机制控制的。     

Effect of dissolved metal ions on PCE decomposition by gamma-rays

This study investigates the effect of initial tetrachloroethylene (PCE) concentration, irradiation dose and dissolved metal ions such as Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+ and Zn2+ on removal of PCE by gamma irradiation. The amount of removed PCE decreased with increase in initial PCE concentration and increased with increase in irradiation dose. PCE removal reached a maximum in the presence of Fe3+, while Cu2+ strongly hindered PCE decomposition. Except for Cu2+, the amount of removed PCE in the presence of metal ions was linearly dependent on the standard reduction potential of the metal ions. The extraordinary inhibition of Cu2+ in PCE removal was caused by the action of Cu2+ as a strong *OH scavenger, that was directly confirmed by electron paramagnetic resonance spectroscopy.     

淀粉基黄原酸盐处理重金属废水的条件优化研究

采用淀粉基黄原酸盐处理含重金属的电镀废水 ,对淀粉基黄原酸盐的用量、pH值和反应时间等条件进行了研究。结果发现 ,1L含氰电镀废水 (含Cr3+15mg/L、Cu2 +3mg/L、Ni2 +9.2mg/L和Zn2 +6mg/L) ,加入 1g淀粉基黄原酸盐 ,调节 pH为 8,搅拌 1h ,过滤 ,处理后的废水中Cr3+、Cu2 +、Zn2 +和Ni2 +残余浓度分别为 0 .0 8mg/L、0 .0 1mg/L、0 .1mg/L和 0 .0 8mg/L。含有重金属盐的残渣 ,可用硝酸处理 ,以回收重金属     

腐殖酸树脂处理含Pb2+、CU2+、Ni2+废水的研究

利用泥炭为原料制备腐殖酸树脂.在动态条件下,研究了腐殖酸树脂对重金属离子Pb2+、Cu2+和Ni2+的吸附效果及吸附条件.同时探讨了腐殖酸树脂对重金属离子Pb2+、Cu2+和Ni2+的吸附与解吸再生机理,吸附机理研究表明,腐殖酸树脂对重金属离子Pb2+、Cu2+和Ni2+的主要吸附形式为离子交换吸附和络合吸附.结果表明,在废水pH值为5.0～7.0,Pb2+、Cu2+和Ni2+浓度分别为50 mg/L,经腐殖酸树脂处理,Pb2+、Cu2+和Ni2+去除率可达98%以上,且处理后废水近中性.含Pb2+、Cu2+和Ni2+电镀废水经腐殖酸树脂处理后,废水中Pb2+、Cu2+和Ni2+含量显著低于国家排放标准.     

Biosorption of Cr3+, Cd2+ and Cu2+ ions by blue-green algae Spirulina sp.: kinetics, equilibrium and the mechanism of the process

The process of biosorption of heavy metal ions (Cr3+, Cd2+, Cu2+) by blue-green algae Spirulina sp. is discussed in this paper. Spirulina sp. was found to be a very efficient biosorbent. The aim of the present study was to investigate quantitatively the potential binding sites present at the surface of Spirulina sp., using both potentiometric titrations and adsorption isotherms. The kinetic experiments showed that the process equilibrium was reached quickly, in less than 5-10 min. It was found that the equilibrium dependence between biosorption capacity and bulk metal ion concentration could be described with Langmuir equation. This suggests that the mechanism of biosorption is rather chemisorption than physical adsorption and was further confirmed by the low surface area associated with physical adsorption and by the presence of cations that appeared in the solution after biosorption. The maximum contribution of physical adsorption in the overall biosorption process was evaluated as 3.7%. It was proposed that functional groups on the cell surface contributed to the binding of metal ions by a biosorbent via equilibrium reaction. Three functional groups capable of cation exchange were identified on the cell surface. The biomass was described as weakly acidic ion exchanger. Since deprotonation of each functional group depends on pH, the process of biosorption is strongly pH-dependent. This was confirmed in the biosorption experiments carried out at different pH. The contribution of functional groups in the biosorption process was confirmed by chemical modification of the groups. Chemically blocked groups did not show neither biosorption nor ion-exchange capabilities. It has been shown that growth conditions can affect the metal adsorption properties of microalgae. The paper also discusses desorption characteristics of the biosorbent. The criteria for desorption were high elution efficiency and preservation of biosorptive properties. Desorbent that possessed these characteristics was nitric acid.     

弱碱性树脂吸附-解吸苦味酸

考察了水中苦味酸在弱碱性离子交换树脂D301R上的吸附与解吸。研究了吸附热力学、动力学特性及吸附机理。结果表明,树脂在pH=2.7～10.2时,吸附能力最好。等温平衡吸附遵循Freundlich模型。吸附过程为吸热、熵增的自发过程。吸附动力学符合Lagergren准二级速率方程,颗粒内扩散为吸附速率的主要控制步骤,吸附速率常数为7.23×10-5～1.20×10-4g/(mg.min),吸附活化能为19.4 kJ/mol。树脂上吸附的苦味酸可用HNO3+丙酮混合液定量洗脱,洗脱率达99%。静态吸附和脱附的比较结果证实了吸附过程中存在不可逆化学吸附。树脂对苦味酸的吸附主要是通过静电吸附、酸碱络合吸附、氢键吸附等协同作用来完成的。     

Adsorption and desorption of 2,4,6-trichlorophenol onto and from ash as affected by Ag+, Zn2+, and Al3+

Metal cations and organic pollutants mostly co-exist in the natural environment. However, their interactions in adsorption processes have yet to be adequately addressed. In the current study, the effect of inorganic cations with different charges (Ag⁺, Zn²⁺, and Al³⁺) on the adsorption and desorption of 2,4,6-trichlorophenol (TCP) onto and from processed ash derived from wheat (Triticum aestivum L.) straw was investigated. The adsorption and desorption of TCP were both nonlinear; the isotherm and kinetics curves fitted well using the Freundlich equation and a pseudo-second-order model, respectively. The presence of Ag⁺ promoted TCP adsorption, while Zn²⁺ and Al³⁺ reduced TCP adsorption onto ash. The desorption of TCP from ash showed obvious hysteresis, and the presence of Ag⁺, Zn²⁺, and Al³⁺ caused the desorption to be less hysteretic. The suppression of TCP adsorption by Zn²⁺ and Al³⁺ was ascribed to the partial overlapping of adsorption groups between TCP and metal ions. Al³⁺ had a stronger inhibition effect than that of Zn²⁺ due to its higher binding capacity and larger hydrated ionic radius than those of Zn²⁺. Enhanced adsorption of TCP onto ash by Ag⁺ was ascribed to its ability to reduce the competitive adsorption of water molecules on ash surface by replacing the original ions, such as Na⁺ and Ca²⁺, and compressing the hydrated ionic radius of these metal ions. In addition, Ag⁺ was able to bind with the aromatic organic compounds containing π-electrons, which resulted in a further increase of TCP adsorption by ash.     

胺基树脂的合成及对水中重金属离子的吸附特征

研究了使用氯甲基化聚苯乙烯交联微球为前驱体与二乙烯三胺经回流反应合成胺基树脂及其对水中Cd2+和Ni2+的吸附特征。结果表明,胺基官能团成功地嫁接到树脂表面,胺基含量为5.6 mmol/g。胺基树脂对Cd2+和Ni2+的吸附等温线表明,温度的升高有利于吸附,且吸附等温线都符合Langmuir模型。pH值对吸附的影响较大,最佳吸附pH值范围为4~6。2种金属离子在胺基树脂上的吸附都符合准二级动力学方程。     

新型TCAS吸附树脂对水中Cd^2＋的吸附去除研究

通过静态吸附试验，研究一种由超分子受体化合物磺化硫杂杯芳烃（TCAS）与树脂结合的产物——新型TCAS吸附树脂对重金属Cd^2＋的吸附去除性能，并初步探讨了吸附机理。试验研究结果表明，TCAS吸附树脂对Cd^2＋的饱和吸附量为14．45mg/g。当温度为20℃，0．5gTCAS吸附树脂对10mL浓度为5113g／L的Cd^2＋溶液吸附60min时，Cd^2＋的去除率可达到99％以上。pH值是影响TCAS吸附树脂吸附效果的重要因素，在pH=5—9时，Cd^2＋的去除率随着pH值的升高而增大。在试验范围内，TCAS吸附树脂对Cd^2＋吸附符合Freundlich方程。吸附在TCAS吸附树脂上的Cd^2＋可洗脱回收，TCAS吸附树脂也可再生利用。TCAS吸附树脂对重金属Cd^2＋的吸附机理主要归因于TCAS对Cd^2＋的络合作用。     

4A沸石对复合污染水体中Pb2+、Cu2+和Cd2+的去除

采用静态吸附法以4A沸石为吸附剂研究其对复合污染水体中Pb2+、Cu2+和Cd2+的竞争吸附特性,并探讨了影响吸附的环境因素。实验表明,在室温条件下,溶液pH5～6,4A沸石15 mg对10 mL复合污染溶液(Pb2+、Cu2+和Cd2+浓度分别为100 mg/L)吸附20 min时,对溶液中3种重金属的吸附去除率均可达99.8%以上。反应过程中4A沸石对3种重金属的吸附速率大小为Pb2+>Cu2+>Cd2+。复合污染水体中4A沸石对Pb2+、Cu2+和Cd2+的吸附符合Langmuir和Fre-undlich等温吸附方程,相关系数分别为0.9981、0.9901、0.9916和0.9638、0.9194、0.9689。经计算,4A沸石对Pb2+、Cu2+和Cd2+的饱和吸附量分别为129.9 mg/g、107.5 mg/g和99.0 mg/g。4A沸石吸附重金属离子达到吸附平衡的时间较短,对溶液pH值的适应性较好。吸附后的4A沸石可以再生利用,对铅离子洗脱重复利用性较铜离子和镉离子强。     

Heavy metal ion influence on the photosynthetic growth of Rhodobacter sphaeroides

The potential of purple non-sulphur bacteria for bioremediation was assessed by investigating the ability of Rhodobacter sphaeroides strain R26.1 to grow photosynthetically in heavy metal contaminated environments. Bacterial cultures were carried out in artificially polluted media, enriched with the transition metal ions Hg2+, Cu2+, Fe2+, Ni2+, Co2+, MoO4(2-), and CrO4(2-) in millimolar concentration range. For each investigated ion the effect on growth parameters was evaluated. The analysis of concentration-effect curves revealed a differentiated response, indicating that diverse mechanisms of tolerance and/or resistance are involved. Adaptation or selection procedures were not applied, leading to assess intrinsic abilities of coping with these contaminants. The microorganism proved to be highly tolerant to heavy metal exposure, especially towards Co2+, Fe2+ and MoO4(2-). In addition Ni2+ and Co2+ were found to decrease the cellular content of light harvesting complexes. A characteristic behavior was observed with mercuric ions, which produced a significant increase of the lag-phase.     

酸洗废液制取复合亚铁的研制及应用

介绍了利用酸洗废液为原料制备复合亚铁型混凝剂的新方法 ,并用制得的产品应用于电镀和印染废水治理工程。工程应用及实验结果表明 ,对含Ni2 + 、Cu2 + 和Cr6+ 的电镀废水 ,能使Ni2 + 、Cu2 + 出水浓度 <0 .1mg/L ,Cr6+ 未检出 ,还能处理数种化学镀废液。对印染废水 ,COD去除率和脱色率可分别达到 84 %和 98%以上 ,值得进一步研究和推广