高岭土尾矿对铬(Ⅵ)离子的吸附行为研究

研究了高岭土尾矿对Cr(Ⅵ)的吸附性行为,探索了Cr(Ⅵ)离子初始浓度、pH值、高岭土尾矿的综合用量、吸附综合时间及溶液吸附综合温度等多种因素对Cr(Ⅵ)溶液吸附综合性能的影响。研究分析结果表明,随初始Cr(Ⅵ)浓度不断增大,高岭土矿岩尾矿对Cr(Ⅵ)浓度吸附的比率逐渐减小;高岭土矿岩尾矿对Cr(Ⅵ)浓度吸附的比率随着高岭土矿石尾矿用量的不断增加而逐渐增大;高岭土尾矿对Cr(Ⅵ)的吸附可在40 min达到平衡;高岭土尾矿的最佳吸附温度为30℃;高岭土尾矿在酸性环境下对Cr(Ⅵ)表现出良好的吸附性能。高岭土尾矿对六价铬的等温吸附符合Freundlich吸附等温方程。结果表明,高岭土尾矿是较为理想的铬离子吸附材料。     

改性锯末对水中Cr(Ⅵ)和Cu(Ⅱ)的吸附性能实验研究

以甲醛或硝酸化学改性的锯末为吸附剂,研究了两种改性锯末对水中Cr(Ⅵ)和Cu(Ⅱ)的吸附性能,探讨了改性锯末的用量、重金属质量浓度、pH、吸附时间等因素对吸附效果的影响,得到了最佳吸附条件。实验结果表明:在废水中Cr(Ⅵ)的质量浓度80mg/L,pH为1.0~2.0,吸附时间2h,改性锯末用量60g/L的条件下,两种改性锯末对铬Cr(Ⅵ)的去除率均在95%以上;当Cu(Ⅱ)的质量浓度为100mg/L、pH5.0~6.0、吸附时间90min、锯末用量30g/L时,甲醛改性锯末对Cu(Ⅱ)的去除率高于90%,而硝酸改性锯末对Cu(Ⅱ)的去除率仅有72%。     

二乙烯三胺基木质素吸附Cu2+、Ni2+的性能研究

以木质素与二乙烯三胺原料,通过环氧氯丙烷交联,制得一种新型金属离子吸附剂二乙烯三胺基木质素,通过吸附实验考察了pH、吸附时间及重金属离子浓度对其吸附Cu2+、Ni2+的影响。在pH=5,温度25℃的条件下,二乙烯三胺基木质素对Cu2+、Ni2+的饱和吸附量为44.84mg/g、34.13 mg/g,吸附符合二级动力学吸附方程,吸附过程比较符合Langmuir型等温吸附曲线。     

化学混凝过程对水中铬（VI）吸附的研究

由于混凝过程会对水中的铬(Ⅵ)发生吸附,因此采用混凝过程去除水中的铬(Ⅵ)。考查了三种混凝剂在混凝过程对铬(Ⅵ)的吸附,用最佳混凝剂考查初始浓度、搅拌时间、静置时间以及pH对铬(Ⅵ)吸附的影响。一般选择聚丙烯酰胺作为混凝剂,搅拌时间4min左右,静置5min左右,pH值为7,会对铬(Ⅵ有一个较好的去除效果。化学混凝过程对铬(Ⅵ)的吸附符合拟一级动力学模型。     

壳聚糖碳化改性凹凸棒石对Cr(Ⅵ)的吸附性能

以壳聚糖为生物质碳源,通过一步水热碳化法对凹凸棒石进行亲有机改性,对改性凹凸棒石进行表征,研究了其对Cr(Ⅵ)的静态和动态吸附性能,对其除Cr(Ⅵ)机制进行了初步探讨.结果表明,改性凹凸棒石表面有丰富的羟基、氨基和羧基等有机官能团,壳聚糖碳化产物成功负载于凹凸棒石表面.在实验的pH值范围内,总铬去除率随pH值增加先增大后减小,pH为1和2时总铬去除率分别为11.7%和80.8%,pH为3时总铬去除率降至10.2%.总铬吸附量随Na~+浓度增加而降低.对总铬的吸附等温线符合Langmuir模型,最大吸附量高达204.1 mg/g.改性凹凸棒石对总铬的动态吸附主要受颗粒内扩散控制,在强酸性条件下(pH=2),去除Cr(Ⅵ)是吸附-还原-再吸附的耦合过程.     

改性绿豆壳对工业废水中Cr(Ⅵ)的吸附研究

用绿豆壳作吸附剂,通过改性后对工业废水中铬离子Cr(Ⅵ)进行吸附试验,分别考察了吸附时间、pH、离子浓度、样品用量以及温度对吸附效果的影响。结果表明:吸附率与样品投加量成正相关系,随Cr(Ⅵ)初始浓度的增加而降低;随温度的增加而增大,1. 0000 g改性绿豆壳在pH=2. 0、T=25℃对初始浓度为70 mg/L的Cr(Ⅵ)溶液吸附6 h,吸附率可达95. 40%。因此,改性绿豆壳对六价铬Cr(Ⅵ)具有较好的吸附效果,可作吸附剂用于工业废水中铬Cr(Ⅵ)污染的治理。     

对叔丁基杯[4]芳烃Schiff碱衍生物处理含铬(Ⅵ)废水的研究

以含N,N-二甲基苯胺基团的对叔丁基杯[4]芳烃Schiff碱衍生物为萃取剂对工业含铬(Ⅵ)废水进行萃取处理,考察了水相pH值、振荡时间、干扰离子和萃取温度对铬(Ⅵ)去除率的影响,探讨了萃取与反萃取机理,同时进行了反萃取试验。结果表明,在pH值为1.0,振荡时间为15 min,温度为25℃的条件下,废水中铬(Ⅵ)的去除率可达到95%以上,以NaOH溶液为反萃取剂可对铬(Ⅵ)进行反萃取,反萃取率可达到81.98%,实现了铬(Ⅵ)的回收和萃取剂的循环利用。     

木质素磺酸钠在活性炭/水界面的吸附机理

为了探究木质素磺酸钠在活性炭/水界面的吸附机理,研究了温度、pH 值、无机盐、脲以及直链醇对其吸附动力学及吸附等温线的影响.吸附动力学结果表明,木质素磺酸钠在活性炭/水界面的吸附约在10 min 内快速达到平衡;随着离子强度的增加及脲的加入吸附速率常数增大,pH值增加,吸附速率常数先增大后减小.不同pH值条件下的木质素磺酸钠在活性炭/水界面的吸附等温线符合 Langmuir 方程;随着离子强度增大、脲或直链醇的加入,吸附过程更符合 Freundlich 模型.增加离子强度、降低 pH 值及加入直链醇都可显著提高木质素磺酸钠的平衡吸附量,而脲的加入降低平衡吸附量.在中性条件下木质素磺酸钠主要通过疏水作用和氢键作用吸附在活性炭/水界面,疏水作用有利于加快吸附速率及增加吸附量,该吸附过程不受温度的影响.     

甘蔗废渣吸附废水中的铬离子的研究

采用甘蔗废渣吸附去除废水中的铬离子,在常温下考察p H、甘蔗废渣用量、粒径、铬初始浓度等对铬去除的影响及甘蔗废渣去除铬的动力学。结果表明,Cr(Ⅵ)和Cr(Ⅲ)的去除率随着甘蔗废渣用量的增加而增大,随着甘蔗渣颗粒大小的增加而减小,随着铬离子起始浓度的增加而减小。Cr(Ⅲ)的去除效果随p H的增大而增大,Cr(Ⅵ)的去除效果随p H的增大而减小。铬的去除行为符合准二级模型。甘蔗废渣对Cr(Ⅲ)比Cr(Ⅵ)有较高的吸附能力。为今后甘蔗废渣用于含铬废水的处理提供依据。     

用磺化褐煤处理含铬(Ⅵ)废水的研究

在静态条件下,对以褐煤为原料制备的磺化褐煤处理含铬(Ⅵ)废水进行了研究。研究了溶液pH值、吸附时间、吸附温度、磺化煤的用量、Cr(Ⅵ)起始浓度等因素对磺化褐煤吸附Cr(Ⅵ)的影响,确定了磺化褐煤处理含铬(Ⅵ)废水的最佳条件:溶液的pH为2.0,Cr(Ⅵ)起始质量浓度为40mg/L,吸附温度为70℃,吸附时间为3h,磺化煤用量为80mg,Cr(Ⅵ)去除率达98%以上。同时探讨了磺化褐煤处理含铬(Ⅵ)废水的反应机理。     

竹炭对溶液中微量铬离子的吸附研究

研究了竹炭粒径、加入量、pH值、吸附时间、Cr(Ⅵ)初始浓度等因素对竹炭吸附Cr(Ⅵ)的影响。实验结果表明,竹炭对水中微量Cr(Ⅵ)离子有较好的吸附性能。当Cr(Ⅵ)离子初始浓度为100μg/mL时,在50 mL Cr(Ⅵ)离子溶液中加入0.3 g60目竹炭,pH为2.0,吸附振荡温度为25℃,吸附3 h,Cr(Ⅵ)离子吸附率达99.5%。竹炭对Cr(Ⅵ)离子的吸附可较好地符合Freundlich等温吸附模型。     

Preparation of Silk Sericin/Lignin Blend Beads for the Removal of Hexavalent Chromium Ions

In the present study, novel adsorbents having high adsorption capability and reusability were prepared using agricultural by-products: silk sericin and lignin. Silk sericin and lignin blend beads were successfully prepared using simple coagulation methods for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. A 1 M lithium chloride (LiCl)/dimethyl sulfoxide (DMSO) solvent system successfully dissolved both sericin and lignin and had sufficient viscosity for bead preparation. Compared to the conventional sericin bead adsorbent, sericin/lignin blend beads showed higher Cr(VI) adsorption capacity. The amount of lignin added to the adsorbent greatly affected the adsorption capacity of the beads, and a 50:50 sericin/lignin blend ratio was optimal. Adsorption behavior followed the Freundlich isotherm, which means the adsorption of Cr(VI) occurred on the heterogeneous surface. Cr(VI) adsorption capability increased with temperature because of thermodynamic-kinetic effects. In addition, over 90% of Cr(VI) ions were recovered from the Cr(VI) adsorbed sericin/lignin beads in a 1 M NaOH solution. The adsorption-desorption recycling process was stable for more than seven cycles, and the recycling efficiency was 82%. It is expected that the sericin/lignin beads could be successfully applied in wastewater remediation especially for hazardous Cr(VI) ions in industrial wastewater.     

Metal ion adsorption behavior of lignocellulosic fiber–ethylene vinyl acetate composites

This study describes the applicability of lignocellulosic fiber dispersed in ethylene vinyl acetate (EVA) to adsorb Pb(II), Cr(III), and Cr(VI) ions in aqueous solutions. Water absorption studies revealed that metal‐ion uptake does not only take place on the surface of the adsorbent but ions can also diffuse into the composite. The adsorption of the metal ions under different experimental conditions was studied. Solute concentration, pH, and contact time were used to assess the adsorption capacity and efficiency. The amount of metal adsorbed increased to 7 mg/g with an increase in solute concentration but compromising the efficiency. Adsorption equilibrium was reached after 3 h, when the maximum lead adsorption was above 80%. The optimum pH for the adsorption of Pb(II) and Cr(III) was 6.5, and pH 2.5 was used for the adsorption of Cr(VI). Competitive adsorption revealed the order of adsorption to be: Pb(II) > Cr(VI) > Cr(III). POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

三氯化铁改性膨润土对铬（Ⅵ）的吸附性能研究

通过几种不同金属盐改性的膨润土对模拟含Cr（Ⅵ）废水进行吸附实验,最终得出三氯化铁改性膨润土对cr（VI）的吸附效果最好,并着重研究了三氯化铁改性膨润土去除模拟水样中重金属离子Cr（Ⅵ）的适宜条件。结果表明,当改性膨润土用量为12g·L^-1,pH值为3～5,振荡吸附时间30min,溶液温度25％,起始Cr（Ⅵ）浓度≤20mg／L时,有机膨润土对Cr（Ⅵ）废水的去除率超过95％。     

羊骨炭对Pb(Ⅱ)、Cr(Ⅵ)、Cd(Ⅱ)吸附性能研究

以CO2为活化剂制备羊骨炭,在不同溶液pH、初始浓度、活性炭投加量等条件下,通过动态吸附试验考察羊骨炭对Pb(Ⅱ)、Cr(Ⅵ)和Cd(Ⅱ)的吸附规律,并用Langmuir和Freundlich吸附等温模型对其吸附性能进行了分析。结果表明,当羊骨炭对Pb(Ⅱ)、Cr(Ⅵ)和Cd(Ⅱ)的最佳吸附量分别为:4.2 mg/g、0.07 mg/g和2.7 mg/g时,吸附液的pH值Pb(Ⅱ)、Cd(Ⅱ)为7～8、Cr(Ⅵ)为酸性pH<6;羊骨炭的投加量分别为:0.2、0.7、0.03 g;最佳初始浓度分别为:60 mg/L、15 mg/L、30 mg/L。羊骨炭对3种离子的吸附行为基本符合Langmuir吸附等温模型和Freundlich吸附等温模型,计算得四种离子的最大吸附量分别为:4.854、1.247、0.402 mg/g。     

溴化十六烷基吡啶修饰磁性二氧化硅及其对Cr(Ⅵ)吸附研究

文章主要研究阳离子表面活性剂溴化十六烷基吡啶修饰磁性二氧化硅来制备磁性材料,并对水溶液中的Cr(Ⅵ)吸附条件进行优化,并对吸附热力学行为进行研究。结果表明:材料对Cr(Ⅵ)有良好的吸附行为,对Cr(Ⅵ)吸附的最佳pH为3.0,平衡时间为2 h;重现性良好。材料对Cr(Ⅵ)的吸附符合Langmuir吸附方程,饱和吸附容量为19.98 mg·g-1,是一种具有较好应用前景的Cr(Ⅵ)吸附剂。     

正磷酸活化木质素吸附Cr(Ⅵ)的固定床实验和模型(英文)

The advantage of using an available and abundant residual biomass,such as lignin,as a raw material for activated carbons is that it provides additional economical interest to the technical studies.In the current investigation,a more complete understanding of adsorption of Cr(VI) from aqueous systems onto H3PO4-acid activated lignin has been achieved via microcolumns,which were operated under various process conditions.The practice of using microcolumn is appropriate for defining the adsorption parameters and for screening a large number of potential adsorbents.The effects of solution pH(2-8),initial metal ion concentration(0.483-1.981 mmol·L-1),flow rate(1.0-3.1 cm3·min-1),ionic strength(0.01-0.30 mmol·L-1) and adsorbent mass(0.11-0.465 g) on Cr(VI) adsorption were studied by assessing the microcolumn breakthrough curve.The microcolumn data were fitted by the Thomas model,the modified Dose model and the BDST model.As expected,the adsorption capacity increased with initial Cr(VI) concentration.High linear flow rates,pH values and ionic strength led to early breakthrough of Cr(VI).The model constants obtained in this study can be used for the design of pilot scale adsorption process.     

水葫芦对水中Pb(Ⅱ)的吸附性能研究

通过静态吸附实验,研究了干体水葫芦对水中的重金属离子Pb(II)的吸附性能,考察了吸附剂投加量、重金属溶液起始浓度、溶液起始pH值及吸附时间对Pb(II)去除效果的影响。研究结果表明,水葫芦对Pb(II)吸附效果明显优于桔子皮、木屑和玉米芯屑,具有吸附时间短、投加量少、适应pH值范围广的特点。     

Removal of hexavalent chromium in soil by lignin-based weakly acidic cation exchange resin

The adsorption of Cr(VI) from soil onto lignin-based weakly acidic cation exchange resin (LBR) has been investigated. Lignin is a three-dimensional amorphous polymer composed of methoxylated phenylpropane units. The unique structure and chemical properties render the lignin suitable for the remediation of hexavalent chromium in the soil. Soil column leaching experiments were conducted to optimize the adsorption conditions. The effects of contact time, pH, adsorbent dosage and temperature on the adsorption of Cr(VI) onto the LBR have been investigated. Experiment data were then correlated with Freundlich and Langmuir isotherms. The Langmuir isotherm model fits the experimental data better than the Freundlich isotherm. It was found that the LBR has a high adsorption capability for Cr(VI) (3.95 mg·g^-1) with a removal rate of 91.9%. Thus, LBR can serve as a good absorbent for the reduction of the concentration of Cr(VI) in soil.     

改性粉煤灰处理含铬（Ⅵ）废水的研究

文章对改性粉煤灰处理含铬（VI）废水进行了研究。通过实验考察了改性粉煤灰加入量、吸附时间、吸附温度和废水的pH对废水中铬（VI）去除率的影响。实验结果表明,改性粉煤灰处理含铬（Ⅵ）废水的最佳工艺条件为：改性粉煤灰加入量为1．5g,吸附时间为10min,吸附温度为25℃,废水的pH为6．0。在此条件下可使50mL模拟含铬废水中铬（VI）浓度由10mg／L降到0．47mg／L,铬（VI）去除率达95％以上,达到了国家《污水综合排放标准》。