No abstract

No abstract

Urea is high solubility nitrogen fertilizer. There is major nitrogen pollution in ecosystem. Slow-release nitrogen fertilizer the way to decrease nitrogen form agriculture. Slow-release nitrogen fertilizer the way to decrease nitrogen in agriculture. Slow-release formulations of nitrogen fertilizer were developed based on alginate-gelatin by using calcium chloride as the cross-linker in the egg-box model as hydrogels. Water-retaining ratio, loading behavior, and the release kinetics were examined. The release kinetic rates were investigated by Zero-order kinetic, First-order kinetic, Higuchi, Korsmeyer-Peppas, Weibull, and Hixson-Crowell models. The results showed that the S1G0.5 sample (alginate 1 g and gelatin 0.5 g) was the optimum condition for application as urea slow-release fertilizers because it was a minimal release kinetic rate for 12 hrs. These results indicate that the alginate-gelatin hydrogel can be a slow-release nutrient to plant an environmentally friendly fertilizer.

Zinc oxide-graphitic carbon nitride (ZnO/g-C3N4) composites were synthesized by precipitation method in order to improve photocatalytic activity under visible light. To enhance antimicrobial activity, silver was added into zinc oxide-graphitic carbon nitride (Ag/ZnO/g-C3N4). Ultrastructures of the composite were analyzed by X-ray diffractometry (XRD) and transmission electron microscopy (TEM). Photocatalytic activity of the composites was carried out by degradation of methylene blue solution as a function of contact time. The results revealed that ZnO/g-C3N4 was capable of dye degradation at 96.65%. Addition of Ag into ZnO/g-C3N4 resulted in increase of dye reduction rate. For antibacterial test, Ag/ZnO/g-C3N4 exhibited bactericidal activity against Pseudomonas aeruginosa and Bacillus cereus. For antifungal test, Ag/ZnO/g-C3N4 showed resistance to Aspergillusniger for 7 days. Ag/ZnO-g-C3N4 composite exhibited better photocatalytic and antimicrobial activities compare to ZnO and g-C3N4. These results indicate that precipitation method is a cheap, rapid and efficient method that can be used to synthesize Ag/ZnO-g-C3N4 composites. For further studies, applications of this Ag/ZnO-g-C3N4 composites in microbiological and agricultural fields will be carried out.

No abstract