Research on the non-point source pollution of microplastics.

Microplastics are characterized with universality, persistence and toxicity to aquatic organisms, the pollution of microplastics has attracted worldwide attention. At present, studies on microplastic pollution were mainly focused on the composition, abundance and species of microplastics in water bodies and sediments, and few studies were focused on the source and influence characteristics of microplastics in surface water bodies. Starting from the sources of microplastic pollution in surface water of this paper, the pollution status of agricultural microplastics was analyzed, and the importance and urgency of studying microplastic pollution in agricultural non-point sources were put forward. Therefore, it was intended to provide effective scientific basis and technical support for the control of microplastics non-point source pollution in river basins.

Effect of ultrasound pretreatment on the hydrothermal synthesis of SSZ-13 zeolite.

SSZ-13 zeolite has been identified as effective material for catalysts and membranes for years because of its structure, but the long crystallization time is the main obstacle for the industry application. The sonochemical-assisted method was identified as one of the potential pre-treatment methods which could reduce the formation duration of zeolites as well as other microporous and mesoporous materials. In this work, zeolite SSZ-13 was prepared by ultrasound pretreatment prior to hydrothermal crystallization. For comparison, samples by the conventional pretreatment and hydrothermal method were also prepared. The synthesized powders were characterized by XRD, SEM, BET, FTIR, NMR and TGA. The results showed that the complete crystallization of SSZ-13 synthesized by the ultrasound-assisted hydrothermal method was achieved within 72h, and much faster than conventional hydrothermal synthesis (120h). Furthermore, the ultrasound pretreatment showed very little effect on the structure properties of the final product compared with the conventional aging method.

Synthesis, characterization, and evaluation of phosphated cross-linked konjac glucomannan hydrogels for colon-targeted drug delivery.

Hydrogel systems of konjac glucomannan (KGM) cross-linked with trisodium trimetaphosphate (STMP) were prepared for colon-targeting drug delivery. Swelling degrees of the hydrogels were measured in artificial gastrointestinal fluids and in sodium chloride solution with different concentrations to study their dependence on the cross-linking density and the ionic strength. The absorption of methylene blue was used to characterize the degree of the KGM cross-linking. In vitro release of model drug hydrocortisone was studied in presence and absence of beta -mannanase. KGM cross-linked with STMP was able to retard the release of the poorly water-soluble drug and could be biodegraded enzymatically. Hydrocortisone release was cross-linking density dependent and controlled by degradation of the hydrogles.