A carrier containing primary amine groups was synthesized by the reaction between nitrilon fibre and diethylenetriamine, and papain was immobilized on this kind of carrier by using glutaraldehyde as a coupling agent. The factors involved with the activity recovery of the immobilized papain and the enzymic properties of the resulting immobilized papain were studied in comparison with free papain, for which casein was chosen as a substrate. The results show that the activity recovery of immobilized papain can reach 47.3%, and that the immobilized papain exhibits better environmental adaptability and reusability than free papain.

Utilizing preferential ion exchange of the modified zeolite, the zeo-sequencing batch reactor (SBR) is recommended for a new nitrogen removal process. In this study, natural zeolite was modified by sodium chloride to enhance sorption capacity for ammoniacal nitrogen. The untreated and treated zeolite was characterized by XPS and XRD techniques. The sorption isotherm tests showed that equilibrium sorption data were better represented by the Langmuir model than by the Freundlich model. Treatment of natural zeolite by sodium chloride increased the sorption capacity for ammoniacal nitrogen removal from aqueous solutions. As a result of the continuous bioregeneration of ammonium saturated zeolite-floc in the SBR, the nitrogen removal efficiency of the zeo-SBR was relatively ideal. Scanning electron microscopy results showed that microbes were abundant in the zeo-SBR process.

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Macromolecule antimicrobials have been explored in foundational research and practical application due to their potential merit for reducing the residual toxicity, increasing their efficiency, selectivity, and prolonging the lifetime of the antimicrobial material. In this work, the quaternized poly(styrene)-b-poly(DMAEMA) diblock polymers are synthesized by reversible addition-fragmentation chain transfer polymerization (RAFT). The minimum inhibitory concentration (MIC) evaluation and optical density (OD) method demonstrated that the amphiphilic antibacterial biomaterials have exceptional antibacterial properties. The amphiphilic polycation has an admirable antibacterial property, and these quaternized diblocks are potent biocides and nonhemolytic. The relationship between the structure and activity is discussed with respect to molecular weight of the diblocks and bacteria structural dependence.

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