钠基膨润土对废水中Ni2+,Cu2+的吸附效果

为了提高膨润土吸附废水中Ni2+,Cu2+的效果,对其改性制备了钠基膨润土,考察了吸附时间、废水pH值以及Ni2+和Cu2+初始浓度对自制钠基膨润土吸附Ni2+,Cu2+效果的影响,分析了吸附等温线,并探讨了吸附机理。结果表明:钠基膨润土对Ni2+,Cu2+都有较好的吸附性能;初始阶段(前10 min)吸附很快,之后随时间延长吸附量提高甚微;pH值为6.2时,处理后的水质即可达国家排放标准;随着Ni2+,Cu2+初始浓度增加,去除率先增加后降低,而吸附量迅速增加,Ni2+和Cu2+初始浓度分别为25 mg/L和40 mg/L时,钠基膨润土对Ni2+,Cu2+的去除率均可达98.6%;钠基膨润土对Ni2+,Cu2+的吸附等温线符合Freundlich吸附等温式。     

聚季铵盐聚丙烯酰胺对电镀废水中Ni2+的吸附性能研究

在静态条件下,对聚季铵盐聚丙烯酰胺(PQAAM)吸附含Ni2 的电镀废水进行了研究,探讨了PQAAM用量、废水pH值、吸附时间、吸附温度对去除Ni2 效果的影响.结果表明,在废水pH值为6.0～8.0、Ni2 浓度0～100 mg/L范围内,吸附时间为80 min、吸附温度为20℃时,按Ni2 与PQAAM质量比为1∶30投加PQAAM进行处理,Ni2 去除率可达98%以上.含Ni2 电镀废水经PQAMM吸附后,废水中Ni2 的含量低于国家排放标准.     

聚丙烯腈纤维改性条件优化及其对模拟电镀废水的净化作用

为了寻求低价、环保的电镀废水处理方案,将廉价的聚丙烯腈(PAN)纤维与羟胺试剂反应对PAN纤维进行改性,使其上氰基螯合获得偕胺肟基纤维。通过改变各种改性条件,探讨了改性条件对PAN改性纤维在重金属单离子溶液和多离子混合溶液中吸附性能的影响。结果表明:最佳改性条件为21.2 g/L PAN纤维,27.0 g/L盐酸羟胺,pH值为7.0,70℃下反应2 h;改性PAN纤维对模拟电镀废水中的Cu2+,Zn2+,Ni2+,Pb2+,Cd2+等重金属离子均有较好吸附性能,其中对Cd2+吸附效果最好,吸附量为55 mg/g;在多离子混合溶液中优先选择吸附Cd2+;改性PAN纤维再生效果优良,可重复利用。     

马铃薯淀粉黄原酸酯基高吸水树脂对重金属离子吸附特性的研究

探索了马铃薯淀粉黄原酸酯基高吸水树脂对Ni 2+、Co2+、Zn2+和Cu2+的二元混合溶液的平衡吸附,并对吸附机理进行了初步研究。结果表明:树脂在二元混合溶液中对Cu2+具有较好的选择性吸附能力。当树脂投放量为0.1g、金属离子初始浓度为100mg/L时,马铃薯淀粉黄原酸酯基高吸水树脂对Cu2+的吸附容量可达78.27mg/g。该高吸水树脂对重金属离子的静态吸附过程符合准二级动力学方程,且与高吸水树脂表面的物理吸附有关。     

碳羟基磷灰石对电镀废水中Zn~(2+)的吸附性能

在静态条件下,对碳羟基磷灰石吸附Zn2+的电镀废水进行了研究,探讨了碳羟基磷灰石用量、废水pH值、吸附时间、吸附温度对去除Zn2+的影响.结果表明,在废水pH值6.0～7.0,Zn2+浓度0～100mg/L,吸附时间为70 min,吸附温度为35℃条件下,按Zn2+与碳羟基磷灰石质量比为1:35投加碳羟基磷灰石进行处理,Zn2+去除率可达98%以上.合Zn2+的电镀废水经碳羟基磷灰石吸附后,废水中Zn2+的含量低于国家一级排放标准.     

含醚键离子交换树脂对电镀废水中Zn2+的吸附条件

电镀废水中含有大量的Zn2+,严重污染环境,危及人类健康,必须进行有效的处理方可排放.为此,在静态条件下,采用含醚键离子交换树脂对含Zn2+的模拟电镀废水进行了吸附处理,探讨了树脂用量、废水pH值、吸附时间、吸附温度对Zn2+去除效果的影响.结果表明:在废水pH值为4.0,Zn2+浓度0～100 mg/L,吸附时间90min,吸附温度25℃下,按Zn2+与含醚键离子交换树脂质量比为1:20投加含醚键离子交换树脂进行处理,Zn2+去除率可达98%以上;含Zn2+的电镀废水经含醚键离子交换树脂吸附后,废水中Zn2+的含量低于国家一级排放标准.     

PPS基N-甲基咪唑离子交换纤维对As(V)的吸附性能

研究了聚苯硫醚基N-甲基咪唑离子交换纤维(MZ-PPS)对水溶液中As(V)的吸附、解吸和再生性能,并考查了溶液浓度、pH值、温度与纤维用量对As(V)吸附的影响。结果表明,MZ-PPS纤维在pH值为8~9时吸附性能最佳,吸附以单分子层离子交换为主,吸附容量随温度升高而增大,其过程符合准二级动力学模型。该纤维对As(V)的吸附可在15min内达到平衡;浓度为20mg/L的As(V)溶液(25mL)经0.02g纤维吸附处理后,砷残留浓度低于国家对饮用水中残留砷标准(≤0.01mg/L);吸附后的纤维可用1mol/L HCl溶液方便再生(洗脱率达97%),且经5次使用-再生循环后,吸附性能基本无变化,具有很好的实际应用前景。     

浒苔吸附废水中Pb2+的性能及其影响因素

以往,少见浒苔对废水中Pb2+吸附的研究报道。通过浒苔对铅的吸附试验,研究了浒苔对水溶液中Pb2+的吸附性能及影响因素,考察了pH值、Pb2+初始浓度、吸附时间、吸附剂用量等因素对吸附效果的影响。结果表明:浒苔对Pb2+有较强的吸附能力;当含Pb2+废水pH值为4.0时,以1 g/L浒苔处理50 mg/L Pb2+废水,吸附效率可达82%;吸附过程符合Langmuir和Freundlich等温吸附模型。     

酒石酸柱撑水滑石吸附水中的Ni~(2+)的特性研究

采用离子交换法制得酒石酸插层MgAl水滑石(MgAl-TA LDHs),并进行了XRD、IR、SEM、比表面积及孔径分析表征。考察了MgAl-TA LDHs吸附剂对溶液中Ni 2+的吸附能力,探讨了水滑石吸附剂投加量、Ni 2+溶液浓度、pH值以及吸附温度对Ni 2+吸附率的影响,并进行了动力学和热力学特征的研究。结果表明,适宜的水滑石投加量为2g/L,pH值以中性为宜,对于Ni 2+浓度不超过100 mg/L的溶液室温下Ni 2+吸附率在60%以上,而高温有利于提高Ni 2+吸附率。吸附过程符合二级动力学模型,吸附等温曲线可用R-P模型来描述。吸附过程能够自发进行,为吸热过程,属于化学吸附。     

弱酸型酚醛树脂对重金属离子的吸附

研究了以苯酚、氯乙酸及甲醛等为原料合成的弱酸型酚醛树脂对重金属离子Ni2+,Cu2+,Zn2+,Pb2+的吸附性能,考察了吸附时间、吸附温度、溶液浓度及pH值对该树脂吸附性能的影响。结果表明,在温度为25℃、pH值为4.5的条件下,该树脂对Ni2+,Cu2+,Zn2+,Pb2+的吸附容量可达到2.4×10-3mol/g,去除率均可达到97.5%以上。吸附了重金属离子的树脂可用5%的盐酸再生并回收重金属离子。     

Identification and characterization of Leucobacter sp. N-4 for Ni (II) biosorption by response surface methodology

In the present study, batch experiments were carried out to characterize and optimize the removal process of Ni (II) by a nickel tolerant strain Leucobacter sp. N-4, which was isolated from the soil samples. The effects of operating parameters with respect to initial solution pH (3.0-6.5), initial nickel concentration (50-100mg/L) and biomass dosage (1-10 g/L) on Ni (II) biosorption were investigated by response surface methodology (RSM). The maximal Ni (II) removal efficiency (nearly 99%) was achieved under the following conditions: pH 4.75, biomass dosage 5.38 g/L and initial Ni (II) concentration 53.6 mg/L. The adsorption-equilibrium data fitted well with both Langmuir and Freundlich isotherms. The monolayer adsorption capacity of biomass obtained from Langmuir isotherm was about 19.6 mg/g. Infrared spectrometer (IR) results showed that chemical functional groups (e.g. -NH(2), -OH and COO-M) of the biomass should be the active binding sites for Ni (II) biosorption from aqueous solutions.     

基于不同洗脱剂的单斜晶系钛基锂离子筛的制备及其吸附性能

采用高温固相法,以碳酸锂和二氧化钛为原料合成了锂离子筛前驱体,并分别考察了0.5mol/L盐酸和0.8mol/L过硫酸钠溶液对前驱体的洗脱及产物锂离子筛的吸锂过程。结果表明,0.5mol/L的盐酸作洗脱剂,循环洗脱-吸附5次后离子筛在含锂溶液(等体积0.01mol/L LiCl和0.01mol/L LiOH混合液)中的吸锂量稳定在18mg/g左右;0.8mol/L的过硫酸钠作洗脱剂,5次循环洗脱-吸附后对锂的吸附量约为16mg/g;吸锂过程适宜用伪二级动力学模型描述,且过硫酸钠的洗脱及所得离子筛的吸附动力学性能均优于盐酸作为洗脱剂的情况;过硫酸钠作洗脱剂有助于改善单斜晶系钛基锂离子筛的动力学性能。研究结果有助于拓宽锂离子筛的制备及应用。     

NF/PDMA/MnO2-Co电容电极对低浓度Pb2+的电吸附特性

在泡沫镍基体上进行阳极电沉积制备了NF/PDMA/MnO₂-Co电极,使用FESEM-EDS、XPS和Raman谱、循环伏安和电容吸脱附测试等手段表征了复合电极的结构和评价其电容特性和对Pb²⁺的吸附行为。结果表明,在电流密度为1 mA/cm²、30℃和3 min条件下制备的NF/PDMA/MnO₂-Co复合电极,在Pb²⁺浓度为20 mg/L的模拟废水中有比较高的比电容值(208.8 F/g),对Pb²⁺有较高的吸附容量(59.9 mg/g);PDMA底层与Co掺杂MnO₂表层的协同作用提高了MnO₂电极电容和吸附性能;吸附动力学拟合表明,复合电极的吸附过程受物理、化学吸附混合控制,并受离子传质和孔隙内扩散的限制;电极的稳定性好,4次循环吸附后的吸附量仍达到51.7 mg/g。     

酸改性膨润土吸附去除镍镉离子的研究

在静态条件下,研究了改性膨润土对重金属离子的吸附性能和吸附机理,着重探讨了改性膨润土去除模拟水样中重金属离子Ni2 ,Cd2 的适宜条件及改性膨润土的再生方法.结果表明,改性膨润土对Ni2 ,Cd2 具有较好的吸附性能;pH值是影响改性膨润土对重金属离子吸附的重要因素,不同的金属离子都有其适宜的pH值范围.吸附的最佳条件是pH值5.0～7.0,废水中Ni2 ,Cd2 含量不大于45 mg/L,搅拌时间约60 min.利用改性膨润土吸附处理Ni2 ,Cd2 含量小于45 mg/L的模拟水样,效果很好,Ni2 ,Cd2 的去除率均可分别达到98.5%以上,出水可达到国家排放标准.     

Biosorption of nickel, chromium and zinc by MerP-expressing recombinant Escherichia coli

Escherichia coli hosts able to over-express metal-binding proteins (MerP) originating from Gram-positive (Bacillus cereus RC607) and Gram-negative (Pseudomonas sp. K-62) bacterial strains were used to adsorb Ni(2+), Zn(2+) and Cr(3+) in aqueous solutions. The initial adsorption rate and adsorption capacity were determined to evaluate the performance of the biosorbents. With the expression of MerP protein, the metal adsorption capacity of the recombinant strains for Ni(2+), Zn(2+) and Cr(3+) significantly improved. The cells carrying Gram-positive merP gene (GB) adsorbed Zn(2+) and Cr(3+) at a capacity of 22.3 and 0.98 mmol/g biomass, which is 121% and 72% higher, respectively, over that of the MerP-free host cells. Adsorption capacity of the cells carrying Gram-negative merP gene (GP) also increased 144% and 126% for Zn(2+) and Cr(3+), respectively. Both recombinant strains also exhibited 24% and 5% enhancement in adsorption of Ni(2+) for GB and GP, respectively. The initial adsorption rate of the recombinant biosorbents was also higher than that of the MerP-free host, suggesting an increased metal-binding affinity with MerP expression. Severe cell damage on GB biosorbent was observed after Cr(3+) adsorption, probably due to the metal toxicity effect on the cells.     

磁性复合凝胶球对Pb(Ⅱ)的吸附特性与机制

以海藻酸钠(SA)作为基体前驱材料,通过离子交联法包埋固化L-甲硫氨酸(L-met)和纳米Fe₃O₄形成磁性复合凝胶球SA@Fe₃O₄/L-met。实验探究了SA@Fe₃O₄/L-met在不同pH、投加量和初始离子浓度条件下对Pb(Ⅱ)吸附能力的影响。结果表明,在pH=5、投加量为0.5 g·L?1、初始浓度为20 mg·L?1时,SA@Fe₃O₄/L-met对Pb(Ⅱ)能达到较好的吸附效率,最大吸附量可达到328.02 mg·g?1,远大于Fe₃O₄@SA与SA的吸附量142.5 mg·g?1和152.8 mg·g?1。吸附动力学和热力学研究表明该吸附过程分别对准二级动力学方程和Langmuir方程的拟合程度更大,且反应过程是一个熵增吸热的过程。最后采用SEM、XPS、VSM等对SA@Fe₃O₄/L-met的结构与性能进行表征分析,发现SA@Fe₃O₄/L-met中的氨基和羧基通过配位反应与Pb(Ⅱ)结合,同时还存在着离子交换作用。经过5次解吸后SA@Fe₃O₄/L-met的吸附量仍能达到210.5 mg·g?1,是一种较理想的环保吸附剂。      

Study the adsorption of phenol from aqueous solution on hydroxyapatite nanopowders

In this study, the hydroxyapatite (HAp) nanopowders prepared by chemical precipitation method were used as the adsorbent, and the potential of HAp nanopowders for phenol adsorption from aqueous solution was studied. The effect of contact time, initial phenol concentration, pH, adsorbent dosage, solution temperature and adsorbent calcining temperature on the phenol adsorption, and the adsorption kinetic, equilibrium and thermodynamic parameters were investigated. The results showed that the HAp nanopowders possessed good adsorption ability to phenol. The adsorption process was fast, and it reached equilibrium in 2h of contact. The initial phenol concentration, pH and the adsorbent calcining temperature played obvious effects on the phenol adsorption capacity onto HAp nanopowders. Increase in the initial phenol concentration could effectively increase the phenol adsorption capacity. At the same time, increase in the pH to high-acidity or to high-alkalinity also resulted in the increase in the phenol adsorption capacity. Increase in the HAp dosage could effectively increase the phenol adsorption percent. However, the higher calcining temperature of HAp nanopowders could obviously decrease the adsorption capacity. The maximum phenol adsorption capacity was obtained as 10.33mg/g for 400mg/L initial phenol concentrations at pH 6.4 and 60 degrees C. The adsorption kinetic and the isotherm studies showed that the pseudo-second-order model and the Freundlich isotherm were the best choices to describe the adsorption behaviors. The thermodynamic parameters suggested that the adsorption of phenol onto HAp was physisorption, spontaneous and endothermic in nature.     

Batch removal of malachite green from aqueous solutions by adsorption on oil palm trunk fibre: equilibrium isotherms and kinetic studies

Oil palm trunk fibre (OPTF)--an agricultural solid waste--was used as low-cost adsorbent to remove malachite green (MG) from aqueous solutions. The operating variables studied were contact time, initial dye concentration, and solution pH. Equilibrium adsorption data were analyzed by three isotherms, namely the Freundlich isotherm, the Langmuir isotherm, and the multilayer adsorption isotherm. The best fit to the data was obtained with the multilayer adsorption. The monolayer adsorption capacity of OPTF was found to be 149.35 mg/g at 30 degrees C. Adsorption kinetic data were modeled using the Lagergren pseudo-first-order, Ho's pseudo-second-order and Elovich models. It was found that the Lagergren's model could be used for the prediction of the system's kinetics. The overall rate of dye uptake was found to be controlled by external mass transfer at the beginning of adsorption, then for initial MG concentrations of 25, 50, 100, 150, and 300 mg/L the rate-control changed to intraparticle diffusion at a later stage, but for initial MG concentrations 200 and 250 mg/L no evidence was found of intraparticle diffusion at any period of adsorption. It was found that with increasing the initial concentration of MG, the pore-diffusion coefficient increased while the film-diffusion coefficient decreased.     

印迹改性磁性交联壳聚糖的表征及吸附性能

为了提高壳聚糖（CS）对Pb²⁺的去除能力,制备了印迹改性磁性交联壳聚糖（Pb-TMCS）,采用FTIR、SEM和XRD对其结构和形态进行了表征,研究了Pb-TMCS对Pb²⁺的吸附、脱附性能及选择性。结果表明：与CS相比,Pb-TMCS的表面孔隙和褶皱增多;Pb-TMCS引入了更多的-OH和-NH₂;Pb-TMCS内部包覆磁性物质Fe₃O₄,Pb-TMCS对 CS的相对选择性系数大于2;Pb-TMCS对Pb²⁺的吸附量从CS的25.57 mg/g提高到45.26 mg/g,脱附3次后仍可重复使用。Pb-TMCS回收方便,对Pb²⁺选择吸附性能好,无污染,在重金属废水处理中具有广阔的应用前景。