乙二胺硅胶复合材料对Zn2+的吸附特性

以γ-氯丙基三氯硅烷为偶联剂,将乙二胺偶合接枝在硅胶表面,合成对锌离子具有吸附作用的乙二胺硅胶复合材料（EDA/SiO2）,考察了Zn2+溶液pH值、初始浓度、吸附温度和吸附时间等因素对复合材料吸附性能的影响。 结果表明,在研究的溶液浓度及温度范围内,Zn2+溶液pH值对EDA/SiO2的吸附量影响显著,吸附的最佳pH值范围在3.0~5.5;Zn2+的吸附平衡数据符合Langmuir吸附模型,热力学数据显示,EDA/SiO2对Zn2+的吸附行为为一吸热且自发进行的过程,升高温度有利于吸附,并对此吸附行为作了解释;吸附动力学数据可用拟二级吸附动力学方程描述,得到的吸附速率常数与溶液初始浓度有关。     

生物吸附剂菹草干粉对Cr(Ⅵ)的吸附性能

开发了高效去除重金属Cr(Ⅵ)污染的生物吸附剂,菹草(Potamogeton crispus)干粉吸附剂,通过单因素分析考察了吸附时间、吸附剂颗粒大小、溶液初始pH值、吸附剂用量、Cr(Ⅵ)初始浓度以及离子强度等对重金属离子Cr(Ⅵ)的吸附性能。 结果表明,对吸附效果影响显著的因素有Cr(Ⅵ)初始浓度、吸附剂颗粒大小、溶液初始pH值和离子强度;其吸附行为符合准二级动力学方程,相关系数为0.9998;菹草对Cr(Ⅵ)的吸附等温线符合Langmuir方程。     

麦秆对重金属pb2+和Cr3+吸附性能的研究

本文以麦秆作为生物吸附剂吸附去除溶液中的pb2+和Cr3+,针对pH值、吸附时间和金属离子浓度等影响吸附的主要因素进行了实验研究,并探讨了麦秆的改性处理.结果表明,溶液pH值是影响吸附的重要因素,麦秆对Pb2+和Cr3++的吸附量随溶液初始pH值的升高而升高.Pb2+和Cr3+在麦秆表面的吸附速度很快,60 min即可...     

大孔树脂对红霉素的吸附动力学研究

利用大孔吸附树脂Amberlite XAD16及HZ816对红霉素的吸附动力学实验,研究了温度、初始浓度、溶液pH值及搅拌速度等因素对吸附过程的影响.结果表明,Amberlite XAD16及HZ816对红霉素的吸附速率符合一级吸附动力学方程及颗粒内扩散方程,过程受液膜扩散阻力及颗粒内扩散阻力共同影响.同时,表观吸附速率常数与颗粒内扩散速率常数均随着温度的升高而增大,随着初始浓度的增大而增大,随着溶液pH值增大而增大,随着搅拌速度加快而增大.     

球形纤维素吸附剂对Cu~(2+)的吸附动力学与热力学研究

以离子液体([Bmim]Cl)为反应介质,丙烯酸为单体,对纤维素进行均相接枝共聚,并采用油包水反相悬浮技术制得球形纤维素吸附剂。采用静态吸附实验方法研究了该吸附剂对水溶液中Cu2+的吸附性能,包括各种因素(溶液pH值,溶液初始浓度,吸附时间,吸附温度)对吸附效果的影响。研究结果表明,适当提高溶液pH值,增加溶液初始浓度,以及延长吸附时间都有利于改善吸附效果;球形纤维素吸附剂对Cu2+的吸附符合Langmuir吸附等温式,吸附过程是自发的放热过程;吸附剂对Cu2+的吸附符合二级吸附动力学模型,吸附过程由膜扩散和颗粒内扩散联合控制。球形纤维素吸附剂对Cu2+的具有很好的吸附性并具有良好的再生性能,可以循环使用。     

硅胶负载氨基吡啶的合成及对Ag~+的吸附性能研究

本文以硅胶为载体,通过氯丙基三乙氧基硅烷(CPTS)将2-氨基吡啶负载到硅胶表面,得到硅胶负载氨基吡啶(SG-AP)吸附材料,通过红外光谱、元素分析对其结构进行了表征。研究了SG-AP对Ag+的吸附性能,考察了溶液pH值、接触时间、温度及金属离子初始浓度等因素对吸附性能的影响。结果表明,对Ag+的最佳吸附pH值为6。吸附动力学表明,对Ag+的吸附符合准二级动力学模型,为液膜扩散控制过程。等温吸附表明吸附过程可用Langmuir模型描述,为单分子层吸附。SG-AP对Ag+吸附的热力学参数表明,吸附过程是自发、吸热的过程。     

β-环糊精接枝壳聚糖的合成及其吸附性能

采用乙二醛作为交联物合成了一种β-环糊精接枝壳聚糖,研究了其对水溶液中对硝基苯酚的吸附性能;考察了温度、pH值、吸附时间、酚溶液初始浓度等因素对其吸附性能的影响.结果表明,当吸附时间为20min,pH值为5~6,温度为25℃~35℃,酚溶液初始浓度为80 mg/L时,β-环糊精接枝壳聚糖对对硝基苯酚的吸附性能最佳.     

镁铝类水滑石在Cr(Ⅵ)和对甲基苯酚复合污染中的吸附

以Cr(Ⅵ)、对甲基苯酚为代表污染物,用实验室模拟法研究了镁铝类水滑石（Mg-Al HTlc）对Cr(Ⅵ)的吸附行为。 结果表明,在Mg-Al HTlc/Cr(Ⅵ)/对甲基苯酚体系中,吸附动力学和热力学分别符合准二级动力学方程和Langmuir吸附等温式;溶液中共存的对甲基苯酚会延缓Mg-Al HTlc对Cr(Ⅵ)的吸附速率,但会增加其对Cr(Ⅵ)的吸附量。 一方面,Cr(Ⅵ)与对甲基苯酚产生竞争吸附,竞争作用的大小和溶液中对甲基苯酚与Cr(Ⅵ)的浓度比有关;另一方面,Mg-Al HTlc对对甲基苯酚的吸附可降低体系pH值,增加Cr(Ⅵ)的吸附量,随Cr(Ⅵ)初始浓度的增加,酚离子的竞争能力相对减弱,当Cr(Ⅵ)与对甲基苯酚的质量浓度比大于3时,Cr(Ⅵ)的吸附量增加显著,去除率增强。体系温度升高使Cr(Ⅵ)的吸附量降低。     

新型吸附剂偏磷酸铈对铀酰的吸附性能研究

研究新型吸附剂偏磷酸铈对铀酰离子的吸附行为。分别考察了溶液的pH值、温度、接触时间和铀酰离子初始浓度对偏磷酸铈吸附铀酰离子的影响;通过动力学、热力学以及吸附等温线初步研究了吸附机理;最后探究了共存离子和富里酸对吸附的影响。当溶液的pH值为5、温度为30℃、接触时间为60min、铀酰初始浓度为10~(-3)mol/L时为最佳吸附条件,最大吸附量可达到261.78mg/g;动力学研究表明,偏磷酸铈对铀酰离子吸附行为符合准二级动力学方程;Langmuir吸附等温线模型可以更准确的描述铀酰离子在偏磷酸铈上的吸附过程,说明此吸附过程为单分子层吸附;热力学研究表明,偏磷酸铈对铀酰离子的吸附属于吸热反应,反应自发进行,高温促进吸附行为。     

交联化羟丙基壳聚糖对Cr(Ⅵ)的吸附与结构分析

研究了交联化羟丙基壳聚糖对Cr(Ⅵ)的吸附作用,探讨了溶液的pH值、反应时间、温度、初始浓度等因素对其吸附性能的影响,并且用FTIR、XRD和SEM对吸附前后物质进行了表征与结构分析。实验表明,pH是交联羟丙基壳聚糖吸附Cr(Ⅵ)的主要影响因素。在pH=5时,对Cr(Ⅵ)初始浓度为15mg/L的溶液,可控制温度在20℃左右吸附2h,吸附剂交联羟丙基壳聚糖用量为1g/100mL溶液即能达到满意的吸附效果。吸附后由于交联羟丙基壳聚糖与Cr(Ⅵ)的配位作用使得交联羟丙基壳聚糖的结晶性明显降低;Cr(Ⅵ)的配位使得交联羟丙基壳聚糖的表面形貌发生了改变。     

均苯四甲酸酐改性花生壳粉吸附阳离子红染料的研究

以花生壳粉(PS)为生物基质,甲苯-2,4-二异氰酸酯(TDI)为交联剂,均苯四甲酸酐(PMDA)为改性剂,制备了均苯四甲酸酐改性花生壳粉(PMPS)吸附剂,并研究了PMPS对阳离子红染料吸附效果的影响因素。结果表明,在25℃,吸附时间3 h,pH值为2.0时,PMPS处理浓度为400.0 mg/mL的阳离子红溶液25 mL,最大吸附容量Q为177.2 mg/g,是未改性花生壳粉的2.2倍。改性花生壳粉吸附模式为Langmuir单分子层化学吸附。     

油茶果壳活性炭的制备及其对Cr(Ⅵ)的去除

利用磷酸活化法制备油茶果壳活性炭,并将其作为吸附剂用于去除水溶液中的Cr(Ⅵ),同时探讨了不同参数(Cr(Ⅵ)的初始浓度、吸附剂的用量、pH、温度等)对油茶果壳活性炭吸附Cr(Ⅵ)的影响。结果表明:当温度为293 K,Cr(Ⅵ)初始浓度为250 mg/L,pH为2.0时,Cr(Ⅵ)的最大吸附量可达165.0 mg/L。根据吸附动力学原理,发现其吸附过程遵循拟二级动力学模型。Cr(Ⅵ)的去除程度随Cr(Ⅵ)初始浓度的升高而增加,且其平衡数据与Freundlich模型拟合良好。     

Optimization of Parameters for Cr(VI) Adsorption on Used Black Tea Leaves

Dynamic characteristics of Cr(VI) sorption on used black tea leaves (UBTLs) as a low-cost adsorbent are studied. Batch experiments were conducted to evaluate the effects of Cr(VI) concentration, solution pH and temperature on the removal process. Both of adsorption and reduction, involved in the process, are affected by the processing parameters. The adsorption kinetics is described successfully using pseudo-second order rate equation and the rate constant decreases with increasing the initial concentration of Cr(VI) up to 150 mg/L (for 0.1 g/L UBTLs) then becomes slow. Experimental and calculated kinetic data for equilibrium are well expressed by Langmuir isotherm. The solution pH has a profound effect on the adsorption rate. The rate constant increases linearly with an increase in temperature, and the low value of activation energy of adsorption, 16.3 kJ/mol, indicates that Cr(VI) is easily adsorbed on UBTLs. The maximum Cr(VI) adsorptive conditions, with a minimum reduction, were achieved from the dynamics of operational parameters: the initial Cr(VI) concentration < 150 mg/L (for 0.1 g/L UBTLs); the initial solution pH = 1.54–2.00 and the processing temperature < 50 ^∘C, for the possibility of its practical application.     

Synthesis of Calcium Silicate Hydrate from Coal Gangue for Cr(VI) and Cu(II) Removal from Aqueous Solution

Both the accumulation of coal gangue and potentially toxic elements in aqueous solution have caused biological damage to the surrounding ecosystem of the Huainan coal mining field. In this study, coal gangue was used to synthesize calcium silicate hydrate (C-S-H) to remove Cr(VI) and Cu(II)from aqueous solutions and aqueous solution. The optimum parameters for C-S-H synthesis were 700 °C for 1 h and a Ca/Si molar ratio of 1.0. Quantitative sorption analysis was done at variable temperature, C-S-H dosages, solution pH, initial concentrations of metals, and reaction time. The solution pH was precisely controlled by a pH meter. The adsorption temperature was controlled by a thermostatic gas bath oscillator. The error of solution temperature was controlled at ± 0.3, compared with the adsorption temperature. For Cr(VI) and Cu(II), the optimum initial concentration, temperature, and reaction time were 200 mg/L, 40 °C and 90 min, pH 2 and 0.1 g C-S-H for Cr(VI), pH 6 and 0.07 g C-S-H for Cu(II), respectively. The maximum adsorption capacities of Cr(VI) and Cu(II) were 68.03 and 70.42 mg·g⁻¹, respectively. Furthermore, the concentrations of Cu(II) and Cr(VI) in aqueous solution could meet the surface water quality standards in China. The adsorption mechanism of Cu(II) and Cr(VI) onto C-S-H were reduction, electrostatic interaction, chelation interaction, and surface complexation. It was found that C-S-H is an environmentally friendly adsorbent for effective removal of metals from aqueous solution through different mechanisms.     

Graft copolymerization of epichlorohydrin and ethylenediamine onto cellulose derived from agricultural by-products for adsorption of Pb(II) in aqueous solution

In order to develop a low-cost and high efficient absorbent, cellulose was extracted from peanut hulls, soybean shells and grapefruit peels using 17.5 % NaOH and then copolymerized with epichlorohydrin and ethylenediamine. Infrared spectra and N contents show that the cellulose was copolymerized successfully with the ethylenediamine. Factors affecting the adsorption behavior of Pb(II), such as pH, temperature, ratio of solid to liquid, competitive sorption of various metal ions, initial metal concentration and adsorption time, were then investigated. The adsorption equilibrium could be obtained within 120 min and the kinetic adsorption processes fitted well with the pseudo-second order kinetic model. The isotherm adsorption data fitted well with Langmuir adsorption model and the maximum absorption capacities of the modified peanut hulls, soybean shells and grapefruit peels were 47.8, 101 and 232 mg g^?1, respectively. The competitive adsorption of mixed metal ions demonstrated that Pb(II) was preferentially removed from solution by the modified peanuts shells, soybean shells and grapefruit peels, then Cu(II) and Cr(III). Desorption of Pb(II) from modified peanut hulls, soybean shells and grapefruit peels was effectively achieved in a 1 mol L^?1 HCl solution. Ethylenediamine-modified grapefruit peels exhibited higher absorption performance than the ethylenediamine-modified soybean shells and peanut hulls and can be used as potential low-cost and high efficient absorbents for the removal of lead ions from wastewater.     

氨基功能化纳米Fe3O4磁性高分子吸附剂对废水中Cr(VI)的吸附研究

采用分散聚合法通过共聚、开环反应, 对纳米Fe3O4进行表面功能化修饰, 得到富含NH2官能团的纳米磁性高分子复合材料. 通过透射电镜(TEM)、振动样品磁强计(VSM)、热重差热分析(TGA)、X射线衍射(XRD)、红外光谱(IR)等对其进行表征, 着重研究了其作为吸附剂对Cr(VI)的吸附性能. 结果表明: 该吸附剂对Cr(VI)的吸附能在10 min内达到平衡; 废水溶液pH值能显著影响吸附剂对Cr(VI)的吸附效果, pH为2.5时效果最佳. 废水中Cr(VI)的初始浓度、吸附时间、温度等因素对吸附效果均有不同程度的影响. 结合相应pH值下Cr(VI)的形态分布, 探讨了这种新型材料对Cr(VI)的吸附机理. 结果表明: 其吸附机理及吸附容量与废水中Cr(VI)的离子形式有关; 吸附过程以离子交换与静电引力为主. 等温吸附数据符合Langmuir模型, T＝308 K, pH＝2.5, V＝40 mL时, 吸附剂的饱和吸附容量qm＝25.58 mg/g. 吸附为吸热过程, 焓变ΔH＝8.64 kJ/mol.     

含偕胺肟基纤维对铬离子吸附性能的初步研究

本文制备了一种含胺肟基鳌合纤维,研究了纤维对六价铬吸附性能的影响因素,结果表明,纤维能将六价铬还原为三价铬,吸附量与温度、时间、溶液ｐＨ值有关,在ｐＨ值为２时,纤维对铬的吸附量最大．     

Immobilization of calix[6]arene bearing carboxylic acid and amide groups on aminopropyl silica gel and its sorption properties for Cr(VI)

An aminopropyl silica gel-immobilized calix[6]arene (C[6]APS) containing both amide and acid moieties was prepared from p-tert-butylcalix[6]arene hexacarboxylate derivative and aminopropyl silica gel in the presence of N,N′-diisopropyl carbodiimide coupling reagent. C[6]APS was used to evaluate the sorption properties of Cr(VI) as a sorbent material. In sorption studies, it was observed that C[6]APS was highly effective at pH 1.5 for Cr(VI). The effect of parameters such as pH, sorbent dosage, contact time, initial Cr(VI) concentration and temperature on Cr(VI) sorption; the sorption isotherms were also studied. Maximum sorption capacity was obtained as 3.1 mg g^?1 at pH 1.5 and 25 °C for 1 h and 10.4 mg L^?1 initial Cr(VI) concentration. Thermodynamic parameters such as change in free energy, enthalpy, and entropy were also determined. In the isotherm studies, Langmuir and Freundlich isotherm models were applied and it was found that the experimental data confirmed to Freundlich isotherm model, and the batch sorption capacity of C[6]APS was calculated as 37.66 mg g^?1.     

Biosorption of Cr(VI) from Water Using Biomass of <Emphasis Type="Italic">Aeromonas hydrophila</Emphasis>: Central Composite Design for Optimization of Process Variables

The potential use of biomass of Aeromonas hydrophila for biosorption of chromium from aqueous solution was investigated. The variables (pH, initial Cr(VI) concentration, biomass dose, and temperature) affecting process were optimized by performing minimum number of experimental runs with the help of central composite design. The results predicted by design were found to be in good agreement (R ² = 99.1%) with those obtained by performing experiments. Multiple regression analysis shows that uptake decreases with increase in pH and biomass dose, whereas it increases with increase in temperature and concentration. The maximum removal of Cr(VI) predicted by contour and optimization plots was 184.943 mg/g at pH 1.5, initial Cr(VI) concentration 311.97 mg/L, temperature 60 °C, and biomass dose 1.0 g. The removal of Cr(VI) was governed by adsorption of Cr(VI) as well as its reduction into Cr(III), which further gets adsorbed. The sorption capacity of biomass was calculated from experimental data using Langmuir sorption model and was found to be 151.50 mg/g at 40 °C and pH 1.5, which is comparable to other biosorbents. In addition to this, Dubinin–Radushkevich model was applied, and it was found that nature of sorption was chemisorption.     

Removal of uranium from aqueous solution by using activated palm kernel shell carbon: adsorption equilibrium and kinetics

Activated palm kernel shell carbon (APKSC) was used to remove U(VI) from aqueous solutions in a batch system. The adsorption kinetics, isotherms, and effects of various parameters, such as temperature, contact time, solution pH, adsorbent dosage, and initial U(VI) concentration on the U(VI) adsorption process were studied. Equilibrium was reached after 120 min in the range of studied U(VI) concentrations and temperatures. U(VI) uptake was insignificantly affected by temperature, but was highly pH dependent, and the optimum pH for removal was 5.5. U(VI) removal efficiency increased with the increasing adsorbent dosage. U(VI) sorption capacity increased with increasing initial U(VI) concentration; any further increases in initial U(VI) concentration above a certain point caused insignificant changes in U(VI) sorption capacity. Isotherm data could be described by the Langmuir isotherm model with a maximum U(VI) adsorption capacity of 51.81 mg/g. Kinetic data were fitted to pseudo-first-order and pseudo-second-order equations, which suggested that the U(VI) adsorption onto APKSC was better reproduced by the pseudo-second-order model rather than pseudo-first-order model. Our results indicated that APKSC might be used as a cheap adsorbent in the treatment of uranium-containing wastewater.