BiOCl光催化剂的改性和固定化研究进展

氯氧化铋(BiOCl)是一种具有良好光催化活性的的新型半导体光催化剂,其独特的层状结构和电子性质决定了它在化工、环保、能源等领域有着巨大的应用前景。本文针对BiOCl光催化剂在应用中存在的问题,对BiOCl光催化剂的掺杂改性和固定化研究进展进行了综述,并对BiOCl光催化剂的研究方向及存在问题进行了展望。     

Synthesis of a novel aromatic–aliphatic hyperbranched polyamide and its application in piezoelectric immunosensors

An aromatic–aliphatic AB₂ monomer, 5‐[3‐(4‐aminophenyl)propionylamino]isophthalic acid, prepared from 5‐aminoisophthalic acid and 3‐(4‐nitrophenyl)propionic acid, and the corresponding hyperbranched polyamide were fabricated. Applications in piezoelectric immunosensors as supports for antibody immobilization were studied. The introduction of the hyperbranched polyamide greatly increased the amount of immobilized antibody on the electrode and consequently increased the sensitivity of the complete piezoelectric immunosensor. The investigation of the properties of the sensors indicated that the hyperbranched polyamide was a suitable support for antibody/antigen immobilization. Copyright © 2007 Society of Chemical Industry     

Porcine pancreatic lipase immobilized on polysiloxane–polyvinyl alcohol hybrid matrix: catalytic properties and feasibility to mediate synthesis of surfactants and biodiesel

Polysiloxane–polyvinyl alcohol hybrid matrix was prepared by a sol–gel technique and its capacity to bind porcine pancreatic lipase investigated. The loading of 250 units g^?1 support was shown to be effective, resulting in an immobilized lipase with high catalytic activity. Both free and immobilized lipases were characterized by determining the activity profile as a function of pH, temperature, substrate concentration and thermal stability. Application of the immobilized lipase in non‐conventional biocatalysis for the synthesis of surfactants and biodiesel was also analyzed. Production of sugar fatty acid esters was found to be dependent on the carbohydrate and the highest molar conversion (50% in 3–4 h of reaction) was achieved for substrates containing fructose and lauric or oleic acids. Biodiesel synthesis from babassu oil and ethanol, propanol or butanol was feasible and regardless of the kind of alcohols, results revealed that the immobilized PPL could efficiently convert triglycerides to fatty acid alkyl esters attaining yields varying from 75 to 95%. Copyright © 2007 Society of Chemical Industry     

固定化微生物技术在废水处理中的应用

目前废水处理是环境治理的难题之一,采用固定化微生物进行治理具有一定的优势。本文主要介绍固定化微生物技术在印染废水、含氰废水、高浓度氨氮废水、石油化工废水处理中的应用。     

磷渣基地聚物材料固化砷钙渣的机理

以砷含量为7.63%的砷钙渣为研究对象,利用磷渣基地聚物材料对其进行固化处理,并采用毒性浸出实验考察了砷钙渣及固化体砷毒性浸出特性。结果表明:砷钙渣中砷的毒性浸出浓度可达2 450 mg/L,远超过国家毒性浸出鉴别标准限值(5 mg/L)。考察了不同养护时间、不同p H值(1~12)浸取剂环境下固化体中砷的浸出规律。结果表明:在p H=4~8范围内,砷浸出浓度较小;在酸性(p H4)和碱性(p H8)条件下砷浸出相对较大,但均小于5 mg/L。并考察了固化体中砷形态变化规律,揭示其固化机理。当养护时间为28 d时,固化体中As(Ⅲ)含量由96.3%降至28.8%,其后随着养护时间的变化固化体中As(Ⅲ)含量呈缓慢降低趋势,180 d As(Ⅲ)含量为12.6%,240 d As(Ⅲ)含量为10.8%。磷渣基地聚物固化砷钙渣机理为:磷渣基地聚物材料水化环境和所含的铁氧化物可使高毒性及强迁移性As(Ⅲ)向相对稳定的As(Ⅴ)转化;随时间的变化,磷渣基地聚物材料不断水化,并提供游离Ca2+、Al3+离子,使砷化合物经沉淀反应生成Al-As-O、Ca-As-O难溶性盐,进而降低砷浸出浓度。     

矿物聚合物的合成及其对Cr(Ⅵ)的解毒与固化

以煤矸石为原料、水玻璃和NaOH为碱性激发剂合成矿物聚合物,以添加硫化物的矿物聚合物对Cr(Ⅵ)进行解毒与固化,对固化体进行了检测.结果表明,当硫化物与Cr(Ⅵ)的摩尔比大于3∶1时,矿物聚合物中总铬的浸出浓度小于1 mg/L时,铬固化率大于99％,对Cr(Ⅵ)的最大固化量为1.2％.添加硫化物的矿物聚合物对Cr(Ⅵ)的解毒与固化是基于氧化还原反应,S2-被氧化为S2+(平均化合价),Cr(Ⅵ)被还原为Cr(Ⅲ),Cr(Ⅲ)被矿物聚合物中的-OAl(-)(OH)3吸引并固化在非晶质结构中.     

Combined Spectroscopic and Calorimetric Studies to Reveal Absorption Mechanisms and Conformational Changes of Protein on Nanoporous Biomaterials

In this study the effect of surface modification of mesoporous silica nanoparticles (MSNs) on its adsorption capacities and protein stability after immobilization of beta-lactoglobulin B (BLG-B) was investigated. For this purpose, non-functionalized (KIT-6) and aminopropyl-functionalized cubic Ia3d mesoporous silica ([n-PrNH₂-KIT-6]) nanoparticles were used as nanoporous supports. Aminopropyl-functionalized mesoporous nanoparticles exhibited more potential candidates for BLG-B adsorption and minimum BLG leaching than non-functionalized nanoparticles. It was observed that the amount of adsorbed BLG is dependent on the initial BLG concentration for both KIT-6 and [n-PrNH₂-KIT-6] mesoporous nanoparticles. Also larger amounts of BLG-B on KIT-6 was immobilized upon raising the temperature of the medium from 4 to 55 °C while such increase was undetectable in the case of immobilization of BLG-B on the [n-PrNH₂-KIT-6]. At temperatures above 55 °C the amounts of adsorbed BLG on both studied nanomaterials decreased significantly. By Differential scanning calorimetry or DSC analysis the heterogeneity of the protein solution and increase in Tm may indicate that immobilization of BLG-B onto the modified KIT-6 results in higher thermal stability compared to unmodified one. The obtained results provide several crucial factors in determining the mechanism(s) of protein adsorption and stability on the nanostructured solid supports and the development of engineered nano-biomaterials for controlled drug-delivery systems and biomimetic interfaces for the immobilization of living cells.     

认识“环境敏感型”生物大分子

生物技术在现代生活中扮演着越来越重要的角色。本文着重分析了＂环境敏感型＂大分子及大分子体系在特定环境条件下发生的一些特定的物理和化学性质的变化机理以及利用控制大分子构象得到对特定外界因素敏感的大分子或大分子体系。目的是认识＂环境敏感型＂大分子或大分子体系在生物技术产品的分离纯化上的具体应用。     

Polystyrene-based diazonium salt as adhesive: A new approach for enzyme immobilization on polymeric supports

In this work, a new way for enzyme immobilization was explored and properties of the enzyme immobilized on different polymer films were investigated. In the process, a polystyrene-based diazonium salt (PS-DAS) was synthesized and used as molecular adhesive to immobilize β-glucosidase on the polymeric supports (films of polyethylene, polypropylene and poly(ethylene terephthalate)). The immobilization of β-glucosidase on the polymer surfaces was achieved by sequential depositions of a piece of the polymer films in PS-DAS and the enzyme solutions. The surface modification was investigated by X-ray photoelectron spectroscopy (XPS), water contact angle measurement, and atomic force microscopy (AFM). The activity of the immobilized β-glucosidase was evaluated by measuring its enzymatic activity to the hydrolysis of p-nitrophenyl-β-d-glucopyranoside (pNPG). The optimized reaction conditions (such as pH and temperature), thermal stability, and reusability of the immobilized enzyme on PE films were assayed by using the enzyme-catalyzed reaction. Results show that the polymeric diazonium salt is firmly adhered on the polymer surfaces and the modified surfaces can react with the enzyme to form covalent bonds. The immobilized enzyme shows changes in the optimized pH and temperature for the hydrolysis reaction catalyzed by β-glucosidase. The kinetic parameter (K_m) of the immobilized β-glucosidase is lower than that of its free counterpart. The immobilized enzyme shows significant enhancement in the thermal stability and reasonable reusability. This new approach can be used as a simple and versatile method for protein immobilization.