氨基改性天然沸石的制备及其对Ni~(2+)的吸附行为

根据软硬酸碱原理,在天然沸石表面嫁接上能与金属镍离子发生化学配位作用的氨基基团,制备了氨基改性的天然沸石.用X射线衍射和红外光谱技术对改性前后天然沸石的结构和表面性质进行了表征;研究了氨基改性天然沸石对镍离子的吸附行为.结果表明:氨基改性后的天然沸石仍然保持原来的结构,在其表面嫁接上了氨基基团;氨基改性天然沸石能对镍离子发生快速吸附作用并具有很大的吸附效率和吸附容量;镍离子浓度在60 mg/L时,氨基改性天然沸石在30 min即迅速达到吸附平衡,吸附效果(吸附效率98.6%,吸附容量5.92 mg/g)显著高于未改性的天然沸石;当镍离子浓度高达150 mg/L时,改性天然沸石也有很好的吸附效果.     

聚离子液体作为吸附材料的研究进展

聚离子液体(Polymeric ionic liquid,PIL)兼具离子液体和聚合物的双重优点,克服了离子液体在吸附过程中无形貌、高粘度、难回收及其使用中易流失等问题。通过聚合物设计和制备,不仅可以得到各种结构、尺寸和形貌的PIL材料,还可以提高PIL中离子液体功能基团的利用率。因此,PIL作为一类新型的高分子吸附材料迅速成为分离领域的热点。在介绍PIL的性质、分类和主要合成途径的基础上,总结了国内外近年来PIL在水相吸附中的研究进展。主要讨论了不同聚合物结构,如线性、超支化、交联结构等,对PIL吸附有机吸附质的影响,并分析了PIL功能基团与不同吸附质之间的相互作用机制,如离子交换、静电作用、氢键以及π-π堆叠等。最后,总结了离子液体功能基团和吸附剂结构与PIL吸附效果之间的关系,并对PIL吸附材料的发展进行了展望。     

改性膨润土对水溶液中草甘膦的吸附研究

分别用硫酸和十六烷基三甲基溴化胺（CTMAB）制备酸改性膨润土和有机改性膨润土,系统地研究了这两种改性膨润土对水溶液中草甘膦的吸附行为。结果表明：两种改性土都在碱性条件下吸附效果较好,草甘膦在酸改性膨润土上的吸附主要与表面羟基有关,在CTMAB改性膨润土上的吸附是分配机理起主要作用。草甘膦在酸改性膨润土上的吸附满足Langmuir吸附模型,吸附过程符合伪二级动力学方程,对CTMAB改性膨润土更满足Fkundlich吸附模型,吸附过程符合伪一级动力学方程。     

沸石对溶液中铈离子的吸附性能

采用间歇法研究了沸石对溶液中铈离子的吸附性能,并对它的吸附机理进行了初步探讨,从而为高放废液的处理提供新的技术途径,也可为高放废物的地质处置效果提供一定的参考。研究表明,沸石对溶液中铈离子吸附能力较低,吸附平衡时间较长,约为168小时;固液比1∶50、溶液中铈离子浓度1400mg/l及pH=1.5时,室温下沸石对溶液中铈离子的平衡吸附量约为22.5mg/g,平衡吸附率约为32%,平衡吸附比约为23.50ml/g;初始浓度一定时,平衡吸附量随着沸石加入量的增大逐渐减少,平衡吸附率与平衡吸附比则逐渐增大,但增大的幅度逐渐减小。     

沸石的改性及其除锌效果研究

为改善天然沸石对水中Zn(Ⅱ)的去除效果,采用NaCl、MnO2、NaCl-MnC2对沸石进行改性,并分别详细研究了MnO2制备中各主要因素及NaCl改性液浓度、改性质量体积比等对改性沸石去除Zn(Ⅱ)效果的影响.结果表明,MnO2改性的最佳条件是沸石与KMnO4和MnSO4溶液凝胶化反应30min,陈化2.5d,沸石质量/(沸石质量+理论生成MnOh质量)为0.6、灼烧温度为400℃,NaCl改性的最佳条件是NaCl改性液浓度为1mol/L、沸石质量/NaCl溶液体积为0.04g/L、改性温度为75℃.在最佳MnO2和NaCl改性条件下对沸石进行NaCl-MnO2联合改性,改性后的沸石用于处理Zn2+初始浓度为50mg/L的水样,其对Zn2+的去除率高于NaCl改性沸石和MnO2改性沸石.     

铝交联改性累托石对水溶液中Cr（Ⅵ）的吸附性能

天然累托石（REC）价格低廉,吸附性较强,将其与铝交联剂进行交联反应而制得的铝交联改性累托石（AL-REC）可用于处理含铬电镀废水。用傅立叶变换红外光谱和X射线粉末衍射仪对铝交联改性累托石进行了表征,显示改性后其骨架并没有发生变化,而晶面间距d001由2．37nm提高到2．78nm;研究了静态条件下AL—REC对水溶液...     

钠基累托石对水溶液中镍(Ⅱ)离子的吸附性能

将天然钙基累托石(Ca-REC)经适当处理得到钠基累托石(Na-REC).在静态条件下,研究了Na-REC对水溶液中Ni(Ⅱ)离子的吸附性能和吸附热力学,考察了pH值、离子强度、吸附时间等因素对吸附效果的影响.结果表明,pH值和离子强度是影响吸附的主要因素,离子交换反应和表面配位反应是Na-REC吸附Ni(Ⅱ)离子的主要机理;在25℃、pH=7.0～8.0、吸附时间为3 h、Na-REC用量为6 g/L、Ni(Ⅱ)浓度50 mg/L、离子强度为0.01 mol/L NaNO3的条件下,用Na-REC吸附水溶液中的Ni(Ⅱ)离子,Ni(Ⅱ)离子去除率可达98%以上;Na-REC对Ni(Ⅱ)的吸附是个自发的、反应度很大的过程,吸附符合Freun-dlich模型.     

改性壳聚糖吸附Cr(Ⅵ)的研究进展

壳聚糖是一种来源丰富、无毒无害的天然吸附材料,对污水中Cr(Ⅵ)有较好的吸附效果。介绍了Cr(Ⅵ)在水溶液中的存在形式、分析了壳聚糖吸附Cr(Ⅵ)的机理,综述了化学改性和复合改性两类壳聚糖的研究进展。详细介绍了交联改性壳聚糖、接枝改性壳聚糖、有机材料复合改性壳聚糖、磁性材料改性壳聚糖、复合载体材料改性壳聚糖的结构、活性官能团类别、吸附原理和应用。最后对改性壳聚糖的新材料研发、制备工艺优化、应用拓展等研究方向进行了展望。     

改性沸石对电镀废水中Pb2+、Zn2+、Ni2+的吸附

将天然沸石进行处理制备出多孔质改性沸石颗粒。在静态条件下，研究了改性沸石颗粒对重金属离子Pb^2 ,Zn^2 ,Ni^2 的吸附效果及条件，含Pb^2 ,Zn^2 ,Ni^2 的电镀废水经改性沸石颗粒吸附后，废水中Pb^2 ,Zn^2 ,Ni^2 的含量低于国家排放标准。     

功能化离子液体的合成及对环氧树脂的改性

首先采用阳离子开环聚合法合成端羟基聚环氧氯丙烷(PECH),然后将其与N-乙基咪唑反应,制备咪唑型聚醚离子液体(PIIL),并用红外和核磁谱图对其结构进行表征。再将咪唑型聚醚离子液体与通用型环氧树脂(EP)进行共混,在苯胺固化剂作用下固化成型。用凝胶渗透色谱测定了PECH的相对分子质量及其分布,用红外光谱和差示扫描量热仪对离子液体与环氧树脂复合产物(PIIL/EP)进行了结构表征及热性能测试,研究了PECH相对分子质量及聚醚离子液体的含量对EP冲击强度的影响。结果表明,合成的咪唑型聚醚离子液体是目标产物,当PECH相对分子质量为1000左右时,冲击强度较好。随着PIIL含量的增加,改性后的EP冲击强度大幅度提高,当PIIL用量为EP的50%时,冲击强度高达14.86kJ/m2,固化后的EP明显具有橡胶的弹性。     

Adsorption of Cr(VI) from aqueous solution by hydrous zirconium oxide

A type of ZrO₂·nH₂O was synthesized and its Cr(VI) removal potential was investigated in this study. The kinetic study, adsorption isotherm, pH effect, thermodynamic study and desorption were examined in batch experiments. The kinetic process was described by a pseudo-second-order rate model very well. The Cr(VI) adsorption tended to increase with a decrease of pH. The adsorption data fitted well to the Langmuir model. The adsorption capacity increased from 61 to 66 mg g^?1 when the temperature was increased from 298 to 338 K. The positive values of both ΔH° and ΔS° suggest an endothermic reaction and increase in randomness at the solid–liquid interface during the adsorption. ΔG° values obtained were negative indicating a spontaneous adsorption process. The effective desorption of Cr(VI) on ZrO₂·nH₂O could be achieved using distilled water at pH 12.     

Adsorption of Cr(VI) from aqueous solutions by spent activated clay

Adsorption of Cr(VI) onto spent activated clay (SAC), a waste produced from an edible oil refinery company, was investigated for its beneficial use in wastewater treatment. After pressure steam treatment, SAC was used as an adsorbent. The adsorption kinetic data were analyzed and fitted well in a pseudo-first-order equation and the rate of removal was found to speed up with decreasing pH and increasing temperature. Activation energy for the adsorption process was found to be 4.01–5.47 kcal/K mol. The Langmuir adsorption isotherm was used to fit the equilibrium data and the effect of pH, temperature and ionic strength were studied. The maximum adsorption capacities for Cr(VI) ranged from 0.743 to 1.422 mg/g for temperature between 4 and 40 °C under a condition of pH 2.0. The studies conducted show the process of Cr(VI) removal to be spontaneous at high temperature and endothermic in nature. From the waste utilization and environment point of view, the work carried out is important and useful. Results obtained can serve as baseline data for designing a treatment process using this low-cost adsorbent for the treatment of wastewater rich in Cr(VI).     

Adsorption of Cr(VI) using silica-based adsorbent prepared by radiation-induced grafting

Silica-based adsorbent was prepared by radiation-induced grafting of dimethylaminoethyl methacrylate (DMAEMA) onto the silanized silica followed by a protonation process. The FTIR spectra and XPS analysis proved that DMAEMA was grafted successfully onto the silica surface. The resultant adsorbent manifested a high ion exchange capacity (IEC) of ca. 1.30 mmol/g and the Cr(VI) adsorption behavior of the adsorbent was further investigated, revealing the recovery of Cr(VI) increased with the adsorbent feed and the equilibrium adsorption could be achieved within 40 min. The adsorption capacity, strongly depended on the pH of the solution, reached a maximum Cr(VI) uptake (ca. 68 mg/g) as the pH was in the range of 2.5–5.0. Furthermore, even in strong acidic (4.0 mol/L HNO₃) or alkaline media (pH 11.0), the adsorbent had a sound Cr(VI) uptake capacity (ca. 22 and 30 mg/g, respectively), and the adsorption followed Langmuir mode. The results indicated that this adsorbent, prepared via a convenient approach, is applicable for removing heavy-metal-ion pollutants (e.g. Cr(VI)) from waste waters.     

Adsorption of Cr(VI) on 1,2-ethylenediamine-aminated macroporous polystyrene particles

An adsorbent, 1,2-ethylenediamine-aminated macroporous polystyrene (EDA-PSt) particles was used to adsorb Cr(VI) from aqueous solution. Effect of pH value, contact time, temperature, adsorbent dosage and initial Cr(VI) concentration on adsorption amount of Cr(VI) on EDA-PSt were investigated. The results showed that the adsorption isotherm can be well described by the Langmuir equation and the adsorption kinetics fitted to the pseudo-second-order model. According to Langmuir equation, Q_m was calculated to be 175.75 mg g⁻¹. The breakthrough curve experiment showed that the dynamic adsorption capacity for Cr(VI) on EDA-PSt was 100.06 mg g⁻¹. The adsorbed Cr(VI) could be desorbed by 0.1 mol L⁻¹ NaOH and the desorption ratio was 67.28%.     

磺化褐煤对废水中Cr（Ⅵ）离子的吸附原与还原

在静态条件下，进行了以磺化褐煤作吸附剂、还原剂净化含铬铬废水的实验。研究了含铬废水的ＰＨ值、浓度和接触时间等因素对ＳＢＣ吸附、还原Ｃｒ（Ⅵ）的影响，确定了ＳＢＣ将化含铬废水的最佳条件。结合对实际含Ｃｒ（Ⅵ）废水的吸附、还原净化处理，讨论了ＳＢＣ对电镀废水处理的可行性。     

磺化褐煤对废水中Cr(Ⅵ)离子的吸附与还原

在静态条件下,进行了以磺化褐煤(SBC)作吸附剂、还原剂净化含铬废水的实验。研究了含铬废水的pH值、浓度和接触时间等因素对SBC吸附、还原Cr(Ⅵ)的影响,确定了SBC净化含铬废水的最佳条件。结合对实际含Cr(Ⅵ)废水的吸附、还原净化处理,讨论了SBC对电镀废水处理的可行性     

Adsorption of Cr(VI) from synthetic solutions and electroplating wastewaters on amorphous aluminium oxide

The adsorption behaviour of amorphous aluminium oxide was studied with respect to Cr(VI) in order to consider its application to purify electroplating wastewaters. A batch method was employed using Cr(VI) concentrations ranged from 10 to 200mg/l. The Langmuir model was found to describe the adsorption process well, offering a maximum adsorption capacity of 78.1mg/g. The effect of ionic strength (0-0.1M KNO(3)), pH (3-9) and competitive solutes (molar ratio [Cr(VI)]/[SO(4)(2-)]=1 and 100) on the retention process was evaluated. Cr(VI) adsorption on amorphous aluminium oxide appeared to be dependent on ionic strength with a more pronounced effect in acid conditions. Conversely, adsorption was not affected by pH in acid medium, but decreased when pH sifted to alkaline values. The presence of SO(4)(2-) greatly reduced Cr(VI) removal across the entire pH range when both solutes were present in similar concentrations. Amorphous aluminium oxide also showed a high adsorption capacity when used in the purification of Cr(VI) electroplating wastewaters. The adsorbent doses required to attain more than 90% of Cr(VI) removal varied between 1 and 5 g/l depending on Cr(VI) concentration in wastewaters.     

Adsorption characteristics and separation of Cr(III) and Cr(VI) on hydrous titanium(IV) oxide

A hydrous titanium(IV) oxide was prepared to study the adsorption characteristics and the separation of chromium species. Batch sorption studies have been carried out to determine the effect of pH on the sorption of Cr(III) and Cr(VI) on hydrous TiO2. An excellent separation efficiency of Cr(III) and Cr(VI) was obtained at pH 2. The adsorption percentage of Cr(VI) was above 99%, whereas that of the Cr(III) was less than 1% at this pH. The adsorption isotherm of Cr(VI) on hydrous TiO2 at pH 2 was in good agreement with the Langmuir isotherm. The maximum adsorption capacity of Cr(VI) on TiO2 was 5 mg g(-1). The rate of adsorption of Cr(VI) by hydrous TiO2 with average particle diameter 250 and 500 microm has been studied under particle diffusion controlled conditions. The diffusion coefficients of Cr(VI) for both hydrous TiO2 having average particle diameter of 250 and 500 microm was calculated at pH 2 as 3.84 x 10(-10) m2 s(-1) and 8.86 x 10(-10) m2 s(-1), respectively.     

改性烟煤对废水中Cr(Ⅵ)吸附作用的研究

烟煤用HNO3氧化并在350℃左右煅烧改性后,具有较高的阳离子交换性能.以该改性烟煤作吸附材料处理电镀厂含铬(Ⅵ)废水,在酸性条件下具有较高的还原性和吸附性,可将废水中以CrO2-4和cr2O2-7两种形式存在的Cr(Ⅵ)完全还原成Cr3 ,具有较高的Cr(Ⅵ)去除率.研究表明,废水的pH值、吸附时间、搅拌、吸附温度、改性烟煤的用量和粒度等对Cr(Ⅵ)去除率影响较大,改性烟煤对Cr(Ⅵ)的吸附符合Langmuir方程.     

改性凹凸棒土吸附剂去除水中的Cr(VI)

以凹凸棒土为载体,合成了乙二胺(EDA)改性凹凸棒土(ATP)吸附剂EDA/ATP复合材料。采用FTIR、TGA对吸附剂进行表征,同时将其应用于对水中Cr(VI)的吸附,研究了溶液初始浓度、吸附时间、溶液pH、Cl?与PO₄3?阴离子浓度对吸附的影响。FTIR和TGA结果表明乙二胺已成功接枝到凹凸棒土表面。吸附实验表明,25℃时EDA/ATP复合材料对Cr(VI)的最大吸附容量为153.78 mg·g?1,吸附在800~900 min内达到平衡,吸附符合Freundlich吸附等温模型和拟二级动力学模型;在初始溶液pH为2~10条件下,随着pH的增加,吸附量先增加再降低,pH为3时,吸附量最大;Cl?对吸附影响较小,PO₄3?对吸附的影响较大,当PO₄3?浓度达到20 mmol·L?1时,Cr(VI)最大吸附量下降了83 mg·g?1;实验表明EDA/ATP可作为一种潜在处理水中Cr(VI)的吸附剂。