Modification of pineapple leaf fibers with aminosilanes as adsorbents for H₂S removal

Pineapple leaves were used as a natural fiber source to prepare various modified microcrystalline cellulose (MCC) samples as sorbents for H₂S sorption. Pineapple leaf fibers were first extracted from pineapple leaves, followed by hydrolyzing to produce MCC before various modifications using primary amine (3-aminopropyltrimethoxysilane, APS), secondary amine (N-methyl-3-aminopropyltrimethoxysilane, MAPS), or tertiary amine (N,N-dimethyl-3-aminopropyltrimethoxysilane, DAPS). The characterization results proved that all the aminosilane groups were successfully grafted onto the MCC. In addition, the thermal stability and the porosity of the modified sorbents were enhanced relative to those of unmodified MCC. The H₂S sorption studies of MCC modified with APS, MAPS, and DAPS at 0, 3, or 5%w/w showed that MCC-MAPS had better H₂S sorption performance than MCC-APS and MCC-DAPS, respectively, when comparing the H₂S sorption performance at the same loading level. The optimum H₂S sorption performance of each aminosilane group was achieved from MCC-APS at 5%, MCC-MAPS at 3%, and MCC-DAPS at 5%. An additional study of H₂S sorption of these three sorbents in the presence of CO₂ showed that MCC-DAPS at 5% was the best sorbent for selective H₂S removal. Our results indicated that MCC modified with the aminosilane groups, especially MAPS, were promising materials for H₂S sorption, with potential application in gas separation.