GOLD ADSORPTION FROM ALKALINE AUROCYANIDE SOLUTION BY NEUTRAL POLYMERIC ADSORBENTS

Certain neutral polymeric adsorbents such as the polyacry-lates XAD-7 and XAD-8 were discovered to exhibit modest capacities for the loadiny of gold from alkaline cyanide solutions. The adsorption characteristics of these resins were examined as a function of pH, ionic strength, and temperature. The experimental results suggest that adsorption occurs via ion pair formation and that the adsorption process can be described by the Freundlich adsorption equation. Interestingly, the polyacrylate resins show excellent selectivity for gold with respect to many other cyanoan-ions.     

新型煤基吸附剂吸附硝基苯的机理研究

以神府煤为原料经过超细粉碎、化学处理、复合成型和后处理制得两种煤基超细复合吸附剂MMCA和AHCA,研究了二者对水溶液中硝基苯的吸附性能和吸附机理．结果表明,MMCA和AHCA对硝基苯的吸附过程符合二级吸附动力学模型,MMCA吸附硝基苯的过程由膜扩散控制,而AHCA吸附硝基苯过程由颗粒内扩散控制,求出了吸附速率常数和颗粒内有效扩散系数．MMCA和AHCA对硝基苯的吸附符合Langmuir吸附等温式,其单层饱和吸附量分别为109．89mg／g和229．57mg／g．     

水中硝基苯在柱撑膨润土上的吸附行为

在［OH^-］/［Al³⁺］=2.4的反应条件下,利用Al³⁺与碱液反应制备出Keggin离子,并由此制备出了无机、无机-有机柱撑膨润土,XRD-衍射数据表明,经柱撑后的膨润土层间距明显增大,达1.9 nm以上.研究了硝基苯在4种改性膨润土上的吸附行为,结果表明：经柱撑处理后的膨润土吸附能力明显大于钠基土,其吸附动力学行为遵循Bingham方程和Langmuir方程所描述的规律,平衡吸附量q_e与平衡浓度C_e之间的关系符合Freundlich和Langmuir等温吸附方程,吸附表现为放热的物理吸附和有机质的分配作用.     

乳化液膜提金的研究——氰化浸出贵液中提金及回收氰化钠的工艺研究

本文提出了一种从氰化浸出贵液中提金及回收氰化钠的新工艺流程,建成了10t/d 处理量的自动分散乳化液膜连续逆流分离装置。研究了载体、内相试剂、相比(乳液与原料液体积之比)、外相pH 及分散颗粒大小等影响因素,提出了连续逆流分离装置的操作参数。实验证明:用该工艺流程能有效地从含金1～3 mg/L 的氰化浸出贵液中,将金富集浓缩50倍,同时使排放液中的游离氰根离子浓度低于0.5mg/L,达到国家排放标准。根据中试试验结果,进行了经济估算,证明液膜法较经济合算。     

氧化-负离子化活性炭吸附锌离子

研究了未处理炭和氧化－负离子炭对锌离子的吸附，发现未处理炭对锌离子的吸附符合Langmuir吸附等温线。无论处理炭还是未处理炭其吸附量均受溶液pH值的影响，氧化－负离子化炭对锌离子的吸附要好于未处理炭。     

无机-有机柱撑膨润土对水中苯胺的吸附行为研究

在OH^-和Al^3 的摩尔比为2．4的反应条件下。利用Al^3 与碱液反应制备出Keggin离子。并由此制备出了无机、无机-有机柱撑膨润土。XRD衍射数据表明：经柱撑后的膨润土层间距明显增大。达1．9nm以上。研究了苯胺在4种改性膨润土上的吸附行为。结果表明：经柱撑处理后的膨润土吸附能力明显大于钠基土。其吸附动力学行为遵循Bangham方程和Langmuir方程所描述的规律,平衡吸附量q,与平衡质量浓度pc之间的关系符合Freundlich和Langmuir等温吸附方程。吸附表现为放热的物理吸附和有机质的分配作用。     

多级介孔炭对刚果红染料吸附性能的研究

以商业硅胶为模板,采用硬模板法制备了多级介孔炭,并研究了其对水溶液中刚果红染料的吸附性能.研究结果表明制备的多级介孔炭具有高比表面,大孔容和集中孔径分布以及高效吸附脱除刚果红染料的性能.多级介孔炭对水溶液中刚果红的吸附等温线符合Langmuir吸附模型,且在45℃具有最大吸附量,为446.89mg·g-1.吸附动力学研究表明动力学数据遵循拟二级动力学模型.热力学研究发现,在25～45℃内,刚果红在多级介孔炭上的吸附行为时吸热过程,且是自发进行的.     

变压吸附制氢过程吸附剂性能

研究了Ｈ２ＣＯ２ＣＨ４ＣＯ混合气在活性炭（ＡＣ）和分子筛（ＭＳ）上的变压吸附（ＰＳＡ）过程，各组分在ＡＣ上的吸附能力为：ＣＯ２的大于ＣＨ４的，ＣＨ４的大于ＣＯ的；在ＭＳ上为：ＣＯ的大于ＣＨ４的。并研究了混合气在ＡＣＭＳ复合床层上的ＰＳＡ过程，其中ＡＣ充填于进口端，主要吸附ＣＯ２和ＣＨ４；ＭＳ主要吸附ＣＯ，为复合床层ＰＳＡ过程的模拟计算和设计提供了基础。     

活性炭吸附Zn(Ⅱ)的热力学与机理研究

本文研究了水溶液中活性炭吸附Ｚｎ＾２＋的热力学特性及其机理,测定了不同温度下的吸附等温线。结果表明;在稀溶液中吸附Ｚｎ＾２＋符合Ｌａｎｇｍｕｉｒ模型;活性炭吸附Ｚｎ＾２＋时可能主要是以水合Ｚｎ（Ｈ２Ｏ）＾２＝ｎ形式被吸附的;活性炭表面存在含氧官能团的吸附活性中心;由于吸附水合Ｚｎ＾２＋与炭表面含氧官能团之间相互作用,导致水分子的脱附及Ｈ＾＋的产生,使其热力学函数ΔＳ＾０增加。     

CESIUM ADSORPTION WITH ZEOLITES FROM NUCLEAR HIGH SALT CONTENT ALKALINE WASTES

The sorption of cesium with zeolites was investigated from an alkaline nuclear waste containing sodium aluminate and sodium nitrate. Isotherms at different temperatures and for different sodium concentrations have been assessed; kinetics was investigated in batch tests. Break through curves are reported both for laboratory and pilot plant columns. For a high salt content alkaline solution (MCE) a capacity of 1 mg of Cs per gram of zeolite was found in fixed bed column operation at room temperature.     

PRODUCTION OF LOW-COST CARBON ADSORBENTS FROM AGRICULTURAL WASTES AND THEIR IMPACT ON DYE ADSORPTION

This study concerns utilizing commonly available agricultural wastes like mustard stalk, jute stalk, sesame stalk, wheat straw, bagasse, and rice husk in a proper and efficient way. As a part of this research, activated carbon has been prepared from these wastes by a two-stage activation process with a carbonization stage up to 325°C as a first stage followed by chemical activation using zinc chloride as an activation agent. The effects of temperature, time, and impregnation ratio on activation have been studied. The batch adsorption technique has been utilized to obtain information for treating effluents from the dye industry. Methylene blue dye has been chosen as the standard. Adsorption data have been modeled using the Freundlich and Langmuir adsorption isotherms and first- and second-order kinetic equations and intraparticle diffusion model. Specific surface area was determined by the methylene blue spot test. The results indicate that such carbons can be employed as low-cost alternatives to expensive commercial activated carbon in wastewater treatment to remove water-soluble dyes.     

SORPTION OF PLATINUM GROUP METALS AND GOLD CHLOROCOMPLEXES BY AMINE POLYMERIC SORBENTS

ABSTRACT

The results of an investigation on the sorption of platinum group metals and gold chlorocomplexes by anion-exchangers and complexing sorbents containing amine groups from HC1 solutions are reported. The sorption mechanism is discussed on the base of the obtained extraction data. The complexformation of ruthenium(III) with the amine groups in the sorbent phase was studied by EPR method.     

PRODUCTION OF LOW-COST CARBON ADSORBENTS FROM AGRICULTURAL WASTES AND THEIR IMPACT ON DYE ADSORPTION

This study concerns utilizing commonly available agricultural wastes like mustard stalk, jute stalk, sesame stalk, wheat straw, bagasse, and rice husk in a proper and efficient way. As a part of this research, activated carbon has been prepared from these wastes by a two-stage activation process with a carbonization stage up to 325°C as a first stage followed by chemical activation using zinc chloride as an activation agent. The effects of temperature, time, and impregnation ratio on activation have been studied. The batch adsorption technique has been utilized to obtain information for treating effluents from the dye industry. Methylene blue dye has been chosen as the standard. Adsorption data have been modeled using the Freundlich and Langmuir adsorption isotherms and first- and second-order kinetic equations and intraparticle diffusion model. Specific surface area was determined by the methylene blue spot test. The results indicate that such carbons can be employed as low-cost alternatives to expensive commercial activated carbon in wastewater treatment to remove water-soluble dyes.     

脱水铝污泥对水溶液中磷的吸附作用研究

研究了脱水铝污泥对水中磷的等温吸附特征和动力学过程,考察了3个因素对脱水铝污泥吸附磷的影响.结果表明,脱水铝污泥的等温吸附特征符合Langmuir和Frcundlichh方程,其中Langmuir方程描述更为准确,其最大饱和吸附量为11.1 mg·g-1.脱水铝污泥对磷的吸附作用受脱水铝污泥粒径和初始溶液含量影响较大,受温度影响不大:粒径由小于0.25 mm增大到1.0～2.0 mm时,吸附量由1.847 mg·g-1降低为1.045 mg·g-1;初始磷的质量浓度由5增加到15 mg·L-1时,吸附量由0.857 5 mg·g-1增加到2.396 mg·g-1;25、30、35℃温度下,吸附量分别是1.807、1.854、1.847 mg·g-1.脱水铝污泥吸附除磷的动力学过程符合准2级动力学模型,相关系数均大于0.95;由模型得出的脱水铝污泥对磷的平衡吸附量与试验所得平衡吸附量偏差范围为4%～16%.     

坡缕石黏土吸附Cu~(2+)的动力学

通过提纯的坡缕石黏土对水溶液中Cu~(2+)的静态吸附实验,考察了吸附过程的动力学特征,研究了吸附过程的动力学模型、表观活化能和活化热力学参数,并对吸附速率的控制进行了分析。结果表明:在实验条件下坡缕石黏土对水中的Cu~(2+)具有较快的吸附速率,60min可基本达到平衡;吸附过程能较好地符合Lagergren pseudo-second-order吸附动力学方程,速率常数k_2随温度的升高而增大,随Cu~(2+)初始浓度的增加而减小;吸附过程的表观活化能为18.82kJ/mol,是活化的化学吸附,活化焓为16.26kJ/mol,活化Gibbs自由能为75.40～79.38kJ/mol,活化熵为-198.50 J/(mol·K),活化为吸热过程,是缔合反应机制:吸附速率由液膜扩散和颗粒内扩散共同控制,低浓度时主要受液膜扩散控制,高浓度时颗粒内扩散的影响更为明显。     

合成碳羟基磷灰石对水中苯胺的吸附机理

利用红外光谱、扫描电子显微镜、X射线衍射仪等测试技术对脲素和蛋壳制成的碳羟基磷灰石(carbonate hydroxylapatite,CHAP)样品表面化学组成进行了表征,并考察了pH值、吸附时间和苯胺浓度对CHAP吸附水中苯胺的影响,以及其吸附动力学和热力学特征。结果表明:当pH=6,吸附时间为60min,苯胺初始浓度为30mg/L,CHAP对苯胺的吸附效果更好。该过程可用Langmuir Freundlich等温式进行描述,但更符合Freundlich经验公式。分别采用准一级动力学模型和准二级动力学模型考察吸附动力学行为,2个模型与实验数据之间有很好的相关性。吸附热力学行为表明该吸附过程是放热和自发的。     

含汞金矿堆浸富液沉淀-絮凝法选择性除汞技术

含汞金矿在堆浸喷淋提金过程中汞与金一起被氰化浸出。为消除后续解吸、电解、,台炼以及活性炭再生过程中的汞污染问题,拟对堆浸富液进行除汞预处理,即采用沉淀．絮凝法选择性去除富液中的汞杂质。考察絮凝剂种类（即FeSO4、明矾、AlCl3和PAM）、Na2s加入量、沉淀pH值调节及其氢氧化物沉淀预分离对除汞效果和金损失率的影响。结果表明：（1）堆浸富液中除了Hg^2＋外,还存在较多会消耗Na2S的离子,如Ar^＋、Fe^2＋、Cu^2＋、Zn^2＋ 、Mn^2＋ 矿和Pb^2＋等,因而Na2S实际加入量显著增大,较佳Na2S／Hg质量比为12左右。（2）采用FeSO4＋PAM作为絮凝剂,能显著加快硫化物沉淀物的沉降,极有利于其工业化应用。（3）适当提高堆浸富液的pH值（11左右）,并将产生的氢氧化物沉淀倾滤分离。可以适当降低Na2S加入量,而不影响汞的去除率。     

钢渣吸附除磷机理研究

研究了氨离子和几种阴离子对钢渣吸附除磷效果的影响,探讨了钢渣吸附除磷的机理.结果表明,氨离子、氯离子和硝酸根离子对钢渣吸附除磷基本没有影响,而碳酸根和硫酸根使除磷效果显著降低,这是因为混合溶液中碳酸根、硫酸根和磷酸根之间互相竞争,争夺钢渣中的钙离子.进一步研究表明,饱和钢渣中Ca、Mg-P的质量分数为总磷的80%以上,而Ca-P是Ca、Mg-P的主要成分,因此,钢渣吸附除磷的主要机理是钢渣中溶出的钙离子与磷酸根离子结合形成沉淀.     

花生壳吸附溶液中铀的研究

以废弃物花生壳为吸附剂来吸附水溶液中的铀,研究了花生壳加入量、溶液pH、铀初始质量浓度以及吸附时间等因素对铀吸附效果的影响。结果表明,花生壳对铀具有较好的吸附效果,当pH=4.0、花生壳用量为4 g.L-1、粒径为0.15～0.3 mm、铀初始质量浓度为30 mg.L-1、吸附时间为2.0 h时,铀的去除率达到了97.8%。等温吸附研究表明,花生壳对铀的吸附行为更符合Langmuir等温吸附方程,说明花生壳对铀的吸附是以单分子层吸附(化学吸附)为主,通过拟合得出最大吸附量为5.05 mg.g-1。     

吸附法脱除液体丙烯中硫的化合物

用动态法研究了加压液体丙烯中脱除硫的化合物的吸附性能,测定了影响动态吸附过程的因素,探讨了吸附机理和传质阻力。结果表明:γ-Al_2O_3用于丙烯脱硫,具有吸附净化度高、吸附容量大、选择性好的特点,传质过程中外膜阻力和孔扩散阻力同时并存。