Pengaruh Penambahan Biochar Teraktivasi dalam Matriks Alginat untuk Enkapsulasi Fosfat

Abstract

The majorty of Indonesian farmers still rely on conventional metdhods for applying fertilizer in agriculture. Improrer fertilizer management can have a negative impact on the environment. Plants are only able to absorb a small portion of the nutrients from the applied fertilizer, leaving approximately 70-90% remaining in the soil and potentiallty contaminating the environment. One way to increases fertilizer use efficiency is throught encapsulation. Alginate, as a natural polymer, is often used as a matrix in encapsulation. Biochar, with its high surfacearea and porosity, plays a role in enchancing the ability to absorb and retain nutrients. The produced beads were tested for encapsulation efficiency, swelling and phosphate release. The composition ratio of alginate:biochar effects the physical shape of the produced beads. Beads with a ratio alginate-biochar (2:3) produced and flat shapes beads, compared to beads without biochar, which resulted in round beads with tails. Beads with a high biochar ratio showed better encapsulation efficiency in binding phosphate. Swelling test indicated that swelling increased with soaking time. Alginate/biochar (2:3) beads shows low swelling capacity due to the addition biochar, which can increase the hydrophobicity of the beads. Phosphate release analysis showed that the release of phosphate from alginate-biochar beads had swelling and steady increase pattern over a 16-days observation period. The result showed that beads without biochar had the highest phosphate release value, while beads with a high biochar ratio alginat-biochar (2:3) showed the lowest phosphate release value. The analysis of the Kosmeyer-Peppas model indicates that the release of phosphate from the alginate/biochar matrix follows a Fickian pattern, with an exponent 0.5.