Surface modification of carbon black by oxidation and its influence on the activity of immobilized catalase and iron-phthalocyanines

Catalase immobilization: Current knowledge, key insights, applications, and future prospects - A review

Catalase (CAT), a ubiquitous enzyme in all oxygen-exposed organisms, effectively decomposes hydrogen peroxide (H2O2), a harmful by-product, into water and oxygen, mitigating oxidative stress and cellular damage, safeguarding cellular organelles and tissues. Therefore, CAT plays a crucial role in maintaining cellular homeostasis and function. Owing to its pivotal role, CAT has garnered considerable interest. However, many challenges arise when used, especially in multiple practical processes. "Immobilization", a widely-used technique, can help improve enzyme properties. CAT immobilization offers numerous advantages, including enhanced stability, reusability, and facilitated downstream processing. This review presents a comprehensive overview of CAT immobilization. It starts with discussing various immobilization mechanisms, support materials, advantages, drawbacks, and factors influencing the performance of immobilized CAT. Moreover, the review explores the application of the immobilized CAT in various industries and its prospects, highlighting its essential role in diverse fields and stimulating further research and investigation. Furthermore, the review highlights some of the world's leading companies in the field of the CAT industry and their substantial potential for economic contribution. This review aims to serve as a discerning, source of information for researchers seeking a comprehensive cutting-edge overview of this rapidly evolving field and have been overwhelmed by the size of publications.

Bio-inspired counter-current multiplier for enrichment of solutes

Improving the efficiency of gas separation technology is a challenge facing modern industry, since existing methods for gas separation, including hollow-fiber membrane contactors, vacuum swing adsorption, and cryogenic distillation, represents a significant portion of the world's energy consumption. Here, we report an enhancement in the release rate of carbon dioxide and oxygen of a thermal swing gas desorption unit using a counter-current amplification method inspired by fish. Differing from a conventional counter-current extraction system, counter-current amplification makes use of parallel capture fluid channels separated by a semipermeable membrane in addition to the semipermeable membrane separating the capture fluid channel and the gas release channel. The membrane separating the incoming and outgoing fluid channels allows gas that would normally exit the system to remain in the desorption unit. We demonstrate the system using both resistive heating and photothermal heating. With resistive heating, an increase in release rate of 240% was observed compared to an equivalent counter-current extraction system.

Manganese meso-tetra-4-carboxyphenylporphyrin immobilized on MCM-41 as catalyst for oxidation of olefins with different oxygen donors in stoichiometric conditions

Oxidation of olefins with tert-butyl hydroperoxide (TBHP), tetra-n-butylammonium periodate (TBAP) and potassium peroxomonosulfate (Oxone) in the presence of MCM-41 immobilized meso-tetra-4-carboxyphenylporphyrinatomanganese(III) acetate has been studied. The results of this study show better catalytic performance of the heterogonous catalyst using TBHP as oxidant in comparison with Oxone and TBAP in oxidation of the used olefins with the exception of cyclooctene. However, different order of reactivity of various olefins has been observed in the presence of Oxone and TBHP. In spite of the absence of good electron-withdrawing groups at the periphery of porphyrin ligand, the catalyst was recovered and reused (at least four times) without detectable catalyst leaching or a significant loss of the catalytic efficiency. All results have been obtained in the absence of using excess molar ratios of olefin to the oxidant, commonly employed as a strategy to overcome the instability of metalloporphyrins in oxidative conditions.

Facile, green encapsulation of cobalt tetrasulfophthalocyanine monomers in mesoporous silicas for the degradative hydrogen peroxide oxidation of azo dyes

A facile and green approach that improves the catalytic lifetime of cobalt tetrasulfophthalocyanine (CoTSPc) for the degradation of dyes is presented. Structurally ordered mesoporous silicas (MCM-41, MCM-48 and SBA-15), microporous aluminosilicates (ZSM-5) and macroporous alumina (γ-Al(2)O(3)) with different pore sizes were selected for the immobilization of CoTSPc, and a wide range of pH conditions (pH values from 4 to 12) were tested with the CoTSPc immobilization procedure. In the catalytic oxidation study, CoTSPc that was immobilized to MCM-41 silica (CoTSPc@MCM-41) prepared at a pH of 12 showed the longest catalytic lifetime. The TOC removal and discoloration of C. I. Acid Red 73 was approximately 60% and 82%, respectively, in the presence of CoTSPc@MCM-41 with H(2)O(2) after 3h. These results indicate that MCM-41, which has a matching size between its mesopores (30 Å) and CoTSPc molecules (25 Å), can prevent CoTSPc molecules from aggregating and improve its catalytic lifetime. In addition, the ability of CoTSPc@MCM-41 to degrade other dyes, and the reuse studies, demonstrated that CoTSPc@MCM-41 could be reused for the degradation of most common dyes.