应用静态离子交换法处理电解废酸的研究

采用001×7型阳离子交换树脂对电解废盐酸中Al3+的脱除进行了研究。采用静态试验的方法,分别从吸附和解吸金属离子两个方面进行了研究,得出树脂吸附和解吸Al3+的最佳静态工艺条件:吸附时间10 min,树脂与酸液的体积比9∶25,树脂饱和吸附容量48.76 mg/g;解吸时间15 min,处理的废酸与再生液的体积比2∶1,铝的解吸率维持在65%左右,酸液可循环使用。     

处理高浓度氨氮废水的阳离子交换树脂筛选

目前树脂种类繁多,给处理高浓度氨氮废水的树脂选型带来困难。根据离子交换理论,利用001×7、D61和D001三种阳离子交换树脂,模拟研究了氮肥厂废水（氨氮浓度为915 mg·L^-1）氨氮的吸附等温式,在30～50 min内三种树脂对氨氮的吸附基本可达到平衡,吸附等温线均符合Freundlich吸附模式;进而研究了这三种树脂对废水中氨氮吸附的选择性系数、工作交换容量和离子交换速率。结果表明,用D61树脂处理含高浓度氨氮的废水效果较为理想,可以相对较少的用量,使处理后水质达到相关排放标准的要求。     

甜菊糖苷提取中脱盐脱色树脂的选择及流速对收率的影响

甜菊糖苷的工业提取中,通常以三氯化铁或硫酸亚铁为絮凝剂,对提取液进行絮凝处理。为提高后续吸附树脂的吸附量,改善产品品质,在大孔吸附树脂吸附前,对絮凝液进行脱盐脱色是至关重要的。通过对阳离子树脂001×7、001×14.5、001×16,与阴离子树脂330和D941相互组合,考察了不同组合下脱盐脱色的效果,以及不同流速对甜菊糖苷收率的影响。结果表明,选用阳离子树脂001×14.5与阴离子树脂D941相组合进行脱盐脱色,效果较好,且甜菊糖苷收率可达96.46%;脱盐脱色流速控制在3～4BV/h最佳。     

甜菊糖苷提取中脱盐脱色树脂的选择及流速对收率的影响

甜菊糖苷的工业提取中,通常以三氯化铁或硫酸亚铁为絮凝剂,对提取液进行絮凝处理,达到初步除杂的目的,从而人为引入了大量的铁离子和酸根离子。为提高后续吸附树脂的吸附量,改善产品品质,在大孔吸附树脂吸附前,对絮凝液进行脱盐脱色是至关重要的。对阳离子树脂001×7、001×14.5、001×16,与阴离子树脂330和D941相互组合,考察了不同组合下脱盐脱色的效果,以及不同流速对甜菊糖苷收率的影响。结果表明,选用阳离子树脂001×14.5与阴离子树脂D941相组合进行脱盐脱色,效果较好,且甜菊糖苷收率可达96.46%;脱盐脱色流速控制在3-4BV/h最佳。     

D001型阳离子交换树脂吸附L-苏氨酸

实验考察了温度、pH值、氯化铵和氯化钠浓度对D001型阳离子交换树脂吸附L-苏氨酸的影响,并测定了25 ℃时阳离子交换树脂吸附L-苏氨酸的吸附等温线.结果表明:阳离子交换树脂吸附L-苏氨酸的吸附率随温度的升高呈略下降的趋势,是个放热过程;pH值增大,吸附率下降;溶液中氯化铵或氯化钠浓度增大,吸附率迅速下降,且当氯化铵或氯化钠物质的量浓度达到1.0 mol·L-1时,L-苏氨酸在树脂上吸附量很小;25 ℃时,最大饱和吸附量约为70g·kg-1(树脂).     

离子交换树脂吸附L-色氨酸的动力学研究

通过静态吸附实验,研究了L-色氨酸在001×7型阳离子交换树脂上的等温吸附和吸附动力学特性.采用动边界模型描述L-色氨酸在该树脂上的交换行为,考察了料液浓度、树脂粒径和温度对交换过程的影响.结果表明,L-色氨酸在001×7型阳离子交换树脂上的吸附等温线符合Langmuir等温方程,且随pH降低,树脂的最大平衡吸附量逐渐增大;交换过程的吸附速率随L-色氨酸浓度和温度的升高而增大,但随树脂粒径的增大而减小;离子交换过程的速度控制步骤为颗粒扩散控制.交换过程的反应速率常数k0为1.199×10-5,反应级数a为1.7,表观活化能Ea为19.94kJ·mol-1,并得到了动力学总方程式.     

处理高浓度氨氦废水的阳离子交换树脂筛选

目前树脂种类繁多，给处理高浓度氨氮废水的树脂选型带来困难。根据离子交换理论，利用001×7、D61和D001三种阳离子交换树脂，模拟研究了氮肥厂废水（氨氮浓度为915mg·L^-1）氨氮的吸附等温式，在30-50min内三种树脂对氨氮的吸附基本可达到平衡，吸附等温线均符合Freundlich吸附模式；进而研究了这三种树脂对废水中氨氮吸附的选择性系数、工作交换容量和离子交换速率。结果表明，用D61树脂处理含高浓度氨氮的废水效果较为理想，可以相对较少的用量，使处理后水质达到相关排放标准的要求。     

用于木糖醇脱酸纯化的离子交换树脂的选择

通过试验和生产实践，从众多离子交换剂中选择出001×7、D001、D308（D301）、D114（D113）阴、阳离子交换树脂作为木糖醇脱酸、钝化最理想的离子交换树脂。     

1，3-丙二醇发酵液脱盐用离子交换树脂的筛选

研究了用离子交换树脂处理1,3-丙二醇发酵液,选用6种阳离子交换树脂和3种阴离子交换树脂,以交换容量、电导率和再生时间为指标,考察了树脂的脱盐效果。结果表明：阳离子交换树脂中的D001-cc对1,3-丙二醇发酵液的处理效果最好,150mL树脂的平均交换容量达到240mL,电导率能降到2250gS／cm,再生时间7h;3种阴离子交换树脂中,D301R的去盐效果最好。     

离子交换法分离提取谷氨酸转化液中的γ-氨基丁酸

采用固定化谷氨酸脱羧酶转化谷氨酸生成γ-氨基丁酸,从4种阳离子交换树脂中筛选出交换容量最高的D061型,用于分离谷氨酸转化液中的γ-氨基丁酸。用静态和动态的方法,考察了不同操作条件对固定床离子交换效果的影响。结果表明,D061型树脂最佳吸附条件为pH=4.0,温度40℃,平衡吸附时间17min,吸附量为0.83mol/L。谷氨酸转化液上样的最佳流速为1BV/h。洗脱剂氨水浓度为1.2mol/L,最优流速为1BV/h。经旋转蒸发仪浓缩、醇沉结晶后,可得γ-氨基丁酸样品,其回收率达到80%。样品由X射线衍射图谱进行了验证。     

Anion exchange of uranium from aqueous sulphuric acid solutions: Diffusion kinetics

The ion exchange kinetics of uranium sorption from acidic sulphate solutions onto weak and strong base resins has been studied. In order to facilitate experimentation and analysis, isotopic redistribution experiments of uranyl sulphate ions (with U-235 as a tracer) under conditions of particle diffusion control have been performed. Also, self-diffusion experiments for sulphate ions (with S-35 as a tracer) and counter diffusion measurements involving uranyl sulphate-sulphate exchange have been performed. The ion exchange of uranium is a slow reaction and appears to be particle diffusion controlled at all solution conditions of practical interest. For a weak base resin (Relite MG-1), the self-diffusion coefficient of uranyl sulphate ions changes with particle size, increasing from 1.49 to 4.88 × 10^?9 cm²/s as the particle diameter is reduced from 0.146 to 0.054 cm. With a strong base resin (Dowex-1×8), the self-diffusion coefficient of uranyl sulphate ions remains reasonably constant with varying particle diameter at a value of 1.76 × 10^?9 cm²/s. Sulphate ion self-diffusion coefficients were also constant with particle size (2.50 × 10^?7 cm²/s) and the counter exchange diffusivity lies between the values for the individual species; a typical value is 1.53 × 10^?8 cm²/s. It is argued that resin matrix structure has a significant effect on uranium kinetics and that a knowledge of the relevant diffusion coefficients will provide a rational basis for the design of ion exchange processes and plant equipment.     

阳离子交换树脂催化酸性油脂酯化脱酸

采用阳离子交换树脂为催化剂研究了酸性油脂的酯化脱酸工艺。分别筛选了001×4,001×7,D113,HD-8,CD-552等几种型号的树脂,其中以CD-552催化效果最好。研究了反应时间、醇酸摩尔比和酸性油脂中催化剂质量分数对CD-552催化酯化脱酸效果的影响。在醇酸摩尔比30∶1,反应温度60℃,树脂质量分数5%和反应时间5 h的工艺条件下,酸性油脂经CD-552催化酯化脱酸后,酸值从10.97 mg/g降低到0.689 mg/g。反应后树脂易分离,能够循环使用,有效地解决了传统的脱酸催化剂不足,对以酸性油脂为原料的生物柴油的生产具有应用前景。     

Preparation and characterization of EVAL hollow fiber membrane adsorbents filled with cation exchange resins

EVAL hollow fiber membrane adsorbents filled with powder D061-type cation exchange resin were prepared through dry-wet spinning process, using hydrophilic copolymer EVAL as the fiber substrate. The microstructures of the membrane adsorbents were observed, and the pure water fluxes, BSA rejection, and static adsorption capacities of membrane adsorbents for BSA were measured. The effect of the resin-filled content on membrane performance has been discussed. The results showed that EVAL hollow fiber membrane adsorbents filled with D061-type cation exchange resins had good adsorption capacity, and the adsorption capacity increased with the quantity of the resin-filled content. The static protein adsorption capacity was 77.14 mg BSA/g membrane adsorbents when D061 resin loading content was 65% at pH 4.5.     

Preparation and characterization of EVAL hollow fiber membrane adsorbents filled with cation exchange resins

EVAL hollow fiber membrane adsorbents filled with powder D061-type cation exchange resin were prepared through dry-wet spinning process, using hydrophilic copolymer EVAL as the fiber substrate. The microstructures of the membrane adsorbents were observed, and the pure water fluxes, BSA rejection, and static adsorption capacities of membrane adsorbents for BSA were measured. The effect of the resin-filled content on membrane performance has been discussed. The results showed that EVAL hollow fiber membrane adsorbents filled with D061-type cation exchange resins had good adsorption capacity, and the adsorption capacity increased with the quantity of the resin-filled content. The static protein adsorption capacity was 77.14 mg BSA/g membrane adsorbents when D061 resin loading content was 65% at pH 4.5.     

Macroporous polystyrene resins as adsorbents for the removal of tetracycline antibiotics from an aquatic environment

Six macroporous polystyrene resins (strong‐acid resins D001, D061, D072, and NKC‐9, strong‐base resin D201, and alkalescent resin D370) were selected as adsorbents for removing tetracycline (TC) and doxycycline hydrochloride (DC) from aqueous solutions. The solution pH and ionic strength had significant effects on the sorption of TC and DC. The basic resins D201 and D370 exhibited strong sorption capabilities (70.08–105.60 mg/g) at pH 4–9, but strong‐acid resins showed good sorption abilities only under acidic conditions of pH 2–3 (83.30–95.78 mg/g). The inhibitory effect of the ionic strength was much weaker for D370 than for D201. The adsorption ratio of TC and DC on D201 and D370 were all above 90% when the amount of adsorbent exceeded 50 mg. By performing kinetic experiments, we determined that the pseudo‐second‐order model fit the data best for DC sorption on the six resins and TC sorption on D201 and D370, but the pseudo‐first‐order model fit the data of TC sorption on the four strong‐acid resins better at pH 7.0. Intraparticle diffusion was not the only rate‐controlling step, and an initial external mass transfer or chemical reaction might have existed in the sorption process. The Langmuir equation was the best isotherm equation to describe the sorption with a monolayer sorption maximum larger than 98.04 mg/g under all temperatures. Thermodynamic studies showed that the sorption of TC and DC on the resins was thermodynamically feasible and spontaneous. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40561.     

A thermally regenerable composite sorbent of crosslinked poly(acrylic acid) and ethoxylated polyethyleneimine for water desalination by Sirotherm process

Crosslinked poly(acrylic acid) (XPAA) made by copolymerization of acrylic acid and ethylene glycol dimethacrylate in bulk was further reacted with 80% ethoxylated polyethyleneimine, and the latter insolubilized by treatment with glutaraldehyde. The resulting composite sorbent, XPAA(EPEI.XG), containing carboxylic acid groups and weakly basic tertiary amine groups in close proximity in the same resin bead exhibited thermally regenerable desalination property, simulating the well‐known Sirotherm? resins. For NaCl and MgCl₂, the sorbent has saturation capacities of 0.796 and 0.839 meq/g (dry) sorbent, respectively, at 30°C but less than 0.1 meq/g (dry) sorbent at 80–90°C. The equilibrium sorption data at 30°C fit well to both Langmuir and Freundlich isotherms for single‐component sorption and to Butler‐Ockrent and Jain‐Snoeyink models for bicomponent sorption. Although the sorption of NaCl exhibits a plateau in the pH range of 4–5, that of MgCl₂ increases sharply above pH 4 because of additional sorption by cation exchange at the ionic sites formed at higher pH. The sorption rate data show characteristics of particle‐diffusion controlled ion‐exchange process, yielding diffusivity values of 1.0–1.3 × 10^?6 cm²/s for NaCl and 3.0–3.5 × 10^?7 cm²/s for MgCl₂, in the initial period at 30°C, with the diffusivity falling abruptly in both cases at higher conversions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis of a Green Fuel Additive Over Cation Resins

The synthesis of polyoxymethylene dimethyl ethers (PODE_n), being green diesel fuel additives, from dimethoxymethane (DMM) and paraformaldehyde over three different cation resins, namely NKC‐9, D001‐CC, and D72, in a stirred‐autoclave reactor was investigated. The pore size distribution and surface area were measured with nitrogen adsorption‐desorption. NKC‐9 had a larger exchange capacity, better developed porosity structure, and higher reaction activity than D001‐CC and D72. The effects of reaction temperature, DMM/CH₂O molar ratio, reaction time, and catalyst loading were studied with NKC‐9. A possible mechanism was explored to describe the bond reorganizations during the reactions.     

甜菜糖蜜发酵废液中提取甜菜碱新工艺研究

研究了采用三段离子交换法从甜菜糖蜜发酵废液中提取甜菜碱的工艺条件和影响因素。三段交换分别使用D31 4、D0 0 1及 0 0 1× 7等苯乙烯型离子交换树脂。第一段交换使脱色、脱盐和除杂同时进行 ,免除了活性炭脱色过程。确定了第二段脱盐交换以pH =3为终点 ,使甜菜碱与金属离子彻底分离。第三段为吸附纯化甜菜碱 ,使用 c(HCl) =1 4mol/L为洗脱剂 ,直接制取了盐酸甜菜碱 ,并使洗脱与树脂再生同时进行 ,简化了工艺操作。所得产品纯度达 98%以上 ,收率(对甜菜 )达 90 %以上。