Cheap and Efficient Prosopis Gum-based Hydrogel for Sustained Boron and Zinc Release in Water and Soil

Abstract

Conventional method of fertilizer application leads to loss of plant nutrient through leaching, run-off, volatilisation, denitrification etc. These in turn affect the health of environment directly or indirectly. Fertilizer application through controlled release formulation offers a promising direction by improving proper management of nutrient and by reducing environmental threats. In this aspect, plant polysaccharides are of special interest as they are easily available, safe to environment and easy to modify. Adopting microwave assisted technique, prosopis gum-based hydrogel loaded with boron and zinc was synthesized. The synthesized hydrogel was characterized by elemental analyzer, FTIR, EDX and SEM. The synthesized hydrogel was then employed as a controlled release matrix for sustained release of boron and zinc. Release study of boron and zinc in water revealed that % cumulative release during the span of 6 days were 51-58% and 59-68 % respectively. Similarly, release pattern in soil were found to be 62-74 % and 52-58% respectively during the span of 20 days. Beyond this point, the release patterns were found to be constant. Furthermore, release kinetic studies of boron and zinc in water followed Fickian mechanism (n<0.5) whereas in soil it followed non-Fickian mechanism (n>0.5). The hydrogel was found to exhibit excellent sustained release of boron and zinc with a half-life of 33-57 days and 49-86 days respectively. Hence, in situation where environmental pollution is of great concern and effective utilization of micronutrients is indispensable, the synthesized hydrogel can offer better choice instead of conventional method.