The present work deals with producing water absorbent hydrogels from rice straw (RS) without anypretreatment. The utilization of RS (an undesirable bio waste) for production of the required hydrogels will addhighly to the economic value, contribution reducing the environmental impact of waste disposal and mostimportantly provide a potentially inexpensive alternative biopolymer to the existing commercial hydrogels frompetrochemical origins. The required hydrogels were prepared on a Lab- and Pilot scale via different graftcopolymerization approaches with acrylonitrile, by using a technique which reduces the environmental impact,resulting from loading of waste-water by non-reacted monomer, to a minimum. The prepared hydrogels werecharacterized by using chemical analysis, IR- spectra and thermo gravimetric analysis TGA analysis. As wellas, the role of grafting approach and pH-value on affinity of the hydrogels produced to absorb water (distilledand Nile water) was evaluated. The results obtained show that, grafting of precyanoethylated RS, usingpersulfate-persulfite initiation system, followed by alkali hydrolysis provide hydrogel with relatively higherabsorption capacity towards both distilled and Nile water than using Ferrous sulfate-H2O2 initiation system. Thecandidate hydrogels have no toxic (inhibitory) effect against the most efficient micro-organisms in plants media(rhizosphere).
Hydrogels, Agricultural waste management, Rice straw, Eco-grafting approach, Water absorbent
biopolymer, Biopolymer application