Adsorption characteristics of thorium on silica-based anion exchange resins

To isolate and separate thorium from nitric acid solutions, three silica-based anion exchange resins were synthesized. Batch experiments were carried out to investigate adsorption behavior of thorium in nitric acid solutions. Adsorption at different concentrations of nitric acid and thorium, influence of contact time and coexisting metal ions, and effect of NO3– were investigated in detail. It was found that at high HNO3 concentrations,the resins exhibited higher adsorption capacity and better affinity towards thorium. The adsorption kinetics could be described by the pseudo-second order model equation, while the adsorption isotherms were well correlated by the Langmuir model. The maximum capacity towards thorium species on SiPyR-N4 was evaluated at 27–28 mg/g-resin. The thermodynamic parameters indicated the adsorption was an exothermic reaction. The presence of NO3– was found to promote the retention of the thorium species.

纳米羟基铁改性阴离子交换树脂用于富营养化水体中磷的吸附净化

为探索一种改良的磷酸盐吸附材料,以优化其在去除富营养化水体中无机磷的应用效果,提出了一种纳米羟基铁(FeOOH)与阴离子交换树脂D-201复合的方法。首先将FeOOH分散于阴离子交换树脂D-201中,得到FeOOH@D-201复合树脂。然后进行批量吸附实验,通过比较FeOOH@D-201与纯D-201对磷酸盐的吸附量来评估其改善程度。并采用准二级动力学模型和Langmuir吸附等温线模型进行拟合,从而分析复合树脂的吸附过程及其机理。结果表明,FeOOH@D-201复合树脂的最大磷酸盐吸附量达到了132.1 mg/g,比纯D-201的吸附量提高了46%,突破了常规阴离子交换树脂在去除无机磷应用中的局限性。模型拟合结果表明,其吸附过程与准二级动力学模型和Langmuir模型较吻合,推断吸附机理主要是静电吸引和配位络合的共同作用。FeOOH@D-201经过5次醋酸脱附-吸附再生循环后,吸附剂去除磷酸盐的能力仍然保持在70.4%以上,证实了复合树脂的良好再生性能。

强碱性阴离子交换树脂的钨钼解吸试验研究

研究了以NaOH+NaNO_(3)为解吸剂、H_(2)O_(2)为强氧化剂,联合从ZGA351大孔强碱性阴离子交换树脂中解吸钨、钼。考察了联合解吸剂组成、NaOH浓度、NaNO_(3)浓度、H_(2)O_(2)浓度及加入量、NaOH+NaNO_(3)/H_(2)O_(2)流速比、解吸次数对钨、钼解吸效果的影响。结果表明:在NaOH浓度1.5 mol/L、NaNO_(3)浓度5%、H_(2)O_(2)加入量为理论量1.2倍、H_(2)O_(2)浓度30%、NaOH+NaNO_(3)/H_(2)O_(2)流速比40条件下进行6次解吸,钨、钼解吸率分别达99.48%、99.38%,树脂的钼穿透吸附量107.10 g/L,与新树脂的钼穿透吸附量107.77 g/L相当,说明ZGA351树脂进行一次解吸—循环吸附后对钼的吸附性能基本保持不变;一次解吸液中钨质量浓度3.82 g/L,钼质量浓度10.71 g/L,钼钨比2.80,调酸后可直接投入工业生产后续工段用于制备钼酸铵产品;30次解吸—吸附循环试验结果表明,树脂使用寿命可满足工业生产成本要求。该法同步完成了解吸液氧化和树脂再生,可简化工艺流程,降低生产成本,为大孔强碱性阴离子交换树脂的解吸工艺提供一种可行的工艺路线。

树脂吸附苯磺酸类废水工艺探究

选择高水溶性的对甲苯磺酸作为研究对象,利用大孔弱碱性苯乙烯系阴离子交换树脂对其模拟水、实际工业废水进行吸附研究,探讨苯磺酸类废水资源化处理工艺。研究发现,两级D301树脂可将12%对甲苯磺酸钠模拟废水TOC去除72.5%,且用2 BV(BV为树脂装填层体积)6%氢氧化钠溶液作为脱附剂,其脱附率可达到61.2%。针对实际废水,两级D301树脂串联吸附5 BV(0.25 BV/h流速),TOC去除率可达到48.1%,且能实现脱色。一级树脂第2 BV脱附液与第1 BV洗水混合补碱度至6%后,套用脱附二级吸附树脂,可实现两级树脂再生利用,节约工程中树脂脱附运行成本。

Adsorption of Ce(IV) in nitric acid medium by imidazolium anion exchange resin

N-methylimidazolium functionalized anion exchange resin in NO3 form （RNO3） was prepared and used for adsorption of Ce（Ⅳ） in nitric acid medimn. The adsorption amount increased with shaking time increasing and the adsorption equilibrium was obtained within 180 rain. Ce（Ⅳ） was partially reduced to Ce（Ⅲ） and the reduction percent of Ce（Ⅳ） increased with shaking time increasing. But RNO3 was more stable than other resins due to the high resistance to oxidation. A little increase of adsorption amount was found with concentration of HNO3 increasing. However, the reduction percent of Ce（Ⅳ） decreased with the increase of HNO3 concentration. The addition of NaNO3 decreased the adsorption amount of Ce（Ⅳ） on RNO3 due to the competitive anion exchange reaction. Ce（Ⅳ） was adsorbed on RNO3 in the form of Ce（Ⅳ） anion nitrato-complex. RNO3 and Ce（Ⅳ）-loaded RNO3 were characterized by fourier transform infrared （FT-IR） and thermogravimeric analysis （TGA）. Ce（Ⅳ） could be easily separated from RE（Ⅲ） solution by RNO3.

Preparation of magnetic anion exchange resin and their adsorption kinetic behavior of reactive blue

Magnetic anion exchange resin （MD-1） was prepared from quaternization of magnetic copolymeric resin （glycidyl methacry- late-co-divinylbenzene）. For comparison, magnetic resin MD-0 without quaternization and non-magnetic resin （D-l） were also synthesized for the adsorption process. It was found that the adsorption was mainly contributed to the chemical interaction between quaternary ammonium groups and reactive blue RXHC. Due to the smaller size, MD- 1 had faster adsorption and desorption kinetics than D-1. Coupled with the advantage of easy separation, the magnetic anion exchange resin was considered to be superior to common anion exchange resin in removal of reactive dye.

Adsorption Mechanisms of Heavy Metal Ions from Drinking Water by Weakly Basic Anion Exchange Resins

Heavy metal micro-contaminants can be removed from water sources such as rivers and lakes using variations of conventional treatment technologies. Weakly basic anion exchange resins offer the best ability to remove trace amounts of heavy metals with high selectivity. This paper discusses how weakly basic resins adsorb heavy metals using two different approaches. The removal of mercury, cadmium, and lead ions is based on the fundamental theory of coordination chemistry. The mechanism is not ion exchange but extractive adsorption of heavy metal salts. However, the marked preferential adsorption of chromate by weakly basic anion exchange can be explained using the traditional theory of ion exchange. A lab-scale study produced positive results for the removal of trace amounts of heavy metal ions from drinking water.

Adsorption behavior of benzenesulfonic acid by novel weakly basic anion exchange resins

Two novel weakly basic anion exchange resins（SZ-1 and SZ-2） were prepared via the reaction of macroporous chloromethylated polystyrene-divinylbenzene（Cl-PS-DVB） beads with dicyclohexylamine and piperidine, respectively. The physicochemical structures of the resulting resins were characterized using Fourier Transform Infrared Spectroscopy and pore size distribution analysis. The adsorption behavior of SZ-1 and SZ-2 for benzenesulfonic acid（BA） was evaluated, and the common commercial weakly basic anion exchanger D301 was also employed for comparison purpose. Adsorption isotherms and influence of solution p H, temperature and coexisting competitive inorganic salts（Na2SO4and Na Cl） on adsorption behavior were investigated and the optimum desorption agent was obtained.Adsorption isotherms of BA were found to be well represented by the Langmuir model.Thermodynamic parameters involving ΔH, ΔG and ΔS were also calculated and the results indicate that adsorption is an exothermic and spontaneous process. Enhanced selectivity of BA sorption over sulfate on the two novel resins was observed by comparison with the commercial anion exchanger D301. The fact that the tested resins loaded with BA can be efficiently regenerated by Na Cl solution indicates the reversible sorption process. From a mechanistic viewpoint, this observation clearly suggests that electrostatic interaction is the predominant adsorption mechanism. Furthermore, results of column tests show that SZ-1possesses a better adsorption property than D301, which reinforces the feasibility of SZ-1for potential industrial application.

用DOWEX MSA-1阴离子交换树脂从氯化物溶液中吸附Zn(Ⅱ)试验研究

研究了用DOWEX MSA-1强碱性阴离子交换树脂从氯化物溶液中吸附Zn(Ⅱ),分析了吸附过程热力学和动力学。结果表明:树脂对Zn(Ⅱ)的吸附量随溶液中氯离子质量浓度增大而提高,吸附平衡符合Redlich-Peterson模型;吸附反应过程中吸热,反应可自发进行;准二级动力学模型可以较好地反映吸附动力学过程,颗粒扩散控制吸附速率。

一种强碱性阴离子交换树脂对水中低浓度NO_(3)^(-)-N的吸附性能研究

用Tulsimer A-62MP强碱性阴离子交换树脂进行水中低浓度NO_(3)^(-)-N的去除性能研究。实验结果表明:吸附等温线用Langmuir等温方程拟合最佳,降温有利于吸附的进行,该树脂的平衡吸附量高达21.66 mg/g,树脂吸附NO_(3)^(-)过程中的离子交换速率取决于液膜扩散。该树脂对NO_(3)^(-)具有较好的吸附选择性,pH值对吸附性能影响不大。动态吸附实验在进水NO_(3)^(-)-N浓度20 mg/L,流速1.7 mL/min条件下,1 h即可达到吸附饱和。采用0.5 mol/L NaCl溶液在20 min内可完成再生,再生率95%以上。傅里叶红外光谱表明树脂中的季铵盐基团,在去除硝酸盐过程中起着重要的作用;该树脂对水中低浓度NO_(3)^(-)-N具有良好的吸附性和可再生性。

Selective removal of nitrate by using a novel macroporous acrylic anion exchange resin

An anion exchange resin NDP-5 has been prepared successfully and applied on the selective removal of nitrate from SO_4^（2-）/ NO_3^- binary co-existence system.The composition and morphology of NDP-5 were confirmed by FT-IR and SEM.The NDP-5 resin exhibits the completely different behavior on the adsorption capacity,adsorption kinetic and the effect of the completing anion in the absence or presence of sulfate,compared to D213.And,the resultants of kinetic are well fitted by the pseudo-first-order and pseudo-second-order models.These results are very important to develop novel resins with great features.

Preparation and application of a novel magnetic anion exchange resin for selective nitrate removal

A novel magnetic anion exchange resin NDM-1 was prepared through suspension polymerization and then functionalized with ammonolysis and alkylating agents.Its application for selective removal of nitrate was performed in comparison with MIEX.The results demonstrated that NDM-1 achieved higher efficiency in nitrate removal than MIEX did,with or without the existence of competing anion SO_4^2- ascribed to its longer alkyl chains on exchange sites.Combined with the advantage of easy separation due toγ-Fe_2O_3 implanted,the magnetic anion exchange resin NDM-1 was considered to be superior to MIEX for nitrate removal in practical application.

717阴离子交换树脂吸附磺基水杨酸

采用静态及动态法研究了717强碱阴离子交换树脂对水中磺基水杨酸的吸附解吸性能．实验结果表明,在pH 2．2～12时,该树脂对磺基水杨酸有较强的吸附能力,吸附曲线符合Langmuir等温方程,吸附过程为焓驱动的放热熵减过程,吸附动力学以颗粒内扩散为主．通过实验测得303 K时树脂静态饱和吸附容量为508 mg/g．在315 K下用10％NaCl+2％NaOH溶液可快速洗脱树脂上吸附的磺基水杨酸,洗脱率达99％．该树脂吸附操作简便,易再生,可望用于磺基水杨酸废水的治理及富集回收．

利用弱碱性阴离子交换树脂从硫化后的钨酸钠溶液中吸附除钼

弱碱性阴离子交换树脂(伯胺型)可从钨酸盐溶液中优先吸附MoO_xS_(4-x)^(2-),且负载树脂易于用NaOH解吸,但当钨酸钠溶液中钼含量较低时其对钼的吸附容量很小。为提高其对钼的吸附容量,研究钨酸钠溶液成分及硫化剂种类对钼吸附行为的影响。结果表明:对于含93g/LWO_3的钨酸钠溶液,钼的吸附率和吸附容量随料液中钼浓度的增加而增大;相对于Na_2S,以NaHS作为硫化剂可明显降低溶液的平衡pH值,显著改善钼的硫化效果,从而更有利于钼的吸附;对于含85 g/L WO_3、7.6 g/L Mo、100 g/L Na_2CO_3的钨酸钠溶液,以NaHS作为硫化剂硫化后,经动态吸附得到的钨酸钠溶液中,WO_3与Mo的质量比达到1970:1,除铝率达99.4%,钨损失率仅为1.5%,钼的吸附容量(单位体积的湿树脂吸附的钼的质量)达31 mg/mL。经1.0 mol/L NaOH溶液解吸后,钼的解吸率达97.3%。

新型弱碱性阴离子交换树脂对Cr(Ⅵ)的吸附性能

用氯乙酰化聚苯乙烯树脂(PS-Acyl-Cl)代替传统的氯甲基化聚苯乙烯树脂(PS-CH2-Cl),通过其与二乙胺(DEA)的胺化反应得到一种新型弱碱性阴离子交换树脂(PS-Acyl-DEA)。研究了该树脂对C(rⅥ)的静态吸附性能,以期处理含铬废水及铬的富集回收提供理论和实验依据。结果表明,该树脂对C(rⅥ)的吸附量随pH的降低而增加;吸附过程在实验浓度范围内符合Langmuir和Freundlich方程,且最大吸附量达263mg/g,大于文献报道。动力学和热力学研究表明,吸附过程为液膜扩散控制,自发且放热过程。

弱碱性阴离子交换树脂对酸性含铀浸出液中铀的吸附机理

研究弱碱性阴离子交换树脂D301处理酸性含铀浸出液的吸附机理,分析D301载铀饱和树脂淋洗异常的原因,优化D301载铀树脂的淋洗参数。研究结果表明:某酸法地浸浸出液中含不同比例的UO_2^(2+),UO_2SO_4,UO_2(SO_4)_2^(2-)和UO_2(SO_4)_3^(4-)等配合物,D301树脂对UO_2(SO_4)_2^(2-)和UO_2(SO_4)_3^(4-)的吸附是离子交换机理,对UO_2^(2+)和UO_2SO_4吸附是表面络合机理,铀酰络合物与树脂以2种不同的化学键结合是导致淋洗曲线出现2个峰的原因;提高淋洗剂酸质量浓度为30 g/L或提高淋洗剂NaCl质量浓度为90 g/L都可以优化淋洗曲线,其中提高淋洗剂NaCl质量浓度更具实际意义。

三甲铵型阴离子交换树脂的制备及其对Cr(VI)的吸附性能

用氯乙酰化聚苯乙烯树脂代替传统的氯甲基化聚苯乙烯树脂,通过与三甲胺反应得到一种新型的三甲铵型强碱性阴离子交换树脂,对该树脂进行了红外光谱表征、元素分析及微孔结构的测定,同时研究了其对Cr(VI)的静态吸附性能.结果表明,该树脂对Cr(VI)的吸附量随pH的降低而增加,pH=2时最大吸附量达117mg/g.吸附过程在实验浓度范围内符合Langmuir和Freundlich方程,相关系数分别为0.9988和0.9769.动力学研究表明,吸附过程符合Boyd液膜扩散方程,相关系数为0.9927.热力学函数ΔG0<0,表明该吸附过程为自发过程;ΔH0=-3648.16J/mol,说明该吸附过程为放热过程,同时ΔS0=3.98J/(K·mol),说明吸附过程熵增加占主导作用.吸附后用5%的NaOH可以将Cr(VI)洗脱,洗脱率达96%以上.

D301弱碱性阴离子交换树脂吸附Cr(Ⅵ)的研究

实验探索性地采用D301弱碱性阴离子交换树脂去除重金属废水中的C(rⅥ),为开发出一种高效、安全的处理、富集和回收含C(rⅥ)废水的新工艺提供理论和实验依据。静态吸附实验结果表明,该树脂对C(rⅥ)的吸附量随pH的降低而增加,在pH=2时吸附量为17.54 mg/g;吸附平衡过程符合Freundlich方程,且最大吸附量为94.34 mg/g;动力学和热力学研究表明,吸附过程为颗粒扩散控制,自发且放热的,表观吸附活化能为E(a300 mg/L)=16 243.06 kJ/mol;树脂的再生能力强,经过3次再生,树脂的平衡吸附量仅下降了8.54%;动态吸附和洗脱实验表明,以5%NaOH溶液为洗脱剂效果最佳,洗脱液浓度高达6 918.74 mg/L,浓缩了约69倍,且动态洗脱曲线没有托尾现象;该树脂尤其适合处理低浓度含C(rⅥ)废水(≤100 mg/L),且几乎不受流速限制。

不同类型树脂对4种丹参酚酸类成分的动态吸附研究

目的研究3种不同类型树脂对丹参4种水溶性成分(丹参素、原儿茶醛、丹酚酸D、丹酚酸B)的动态吸附特性。方法通过动态吸附及解吸附实验,以4种丹酚酸成分为考察指标,综合比较了大孔树脂、聚酰胺树脂及阴离子交换树脂对各成分的动态泄露曲线、吸附饱和量、动态解吸附曲线和解吸附率。结果 AB-8型大孔树脂适宜于丹酚酸D和丹酚酸B精制分离,其饱和吸附量分别为22.3 mg/g和27.4 mg/g,与聚酰胺树脂相近,远高于201×7型阴离子交换树脂;而阴离子交换树脂对丹参素与原儿茶醛的吸附效果较好,饱和吸附量分别为30.8 mg/g和3.2 mg/g,优于另外两种树脂。结论大孔树脂和阴离子交换树脂在丹参酚酸精制分离时具有互补性,两者联合应用能产生更好的效果。

用201×7强碱性阴离子交换树脂回收氰化物

研究了201X7树脂对氰化物的吸附解吸性能,考察了pH值、温度、氰化物浓度等对吸附的影响,确定了最佳吸附条件为:pH 10～11,室温,静态吸附振荡15 min,并选择中性NaCl作为解吸剂,取得了良好的解吸效果.确定了湿树脂对氰化物的静态饱和吸附容量为25.39 mg/mL,动态饱和吸附容量为27.43 mg/mL.探讨了201×7树脂对氰化物吸附的热力学及动力学规律,确定了吸附和解吸的速率常数分别为1.01×10-2和2.12×10-2 s-1.吸附过程符合Freundlish经验等温式.通过实验初步确定该树脂可用于氰化物回收及处理.