Bioadsorbent based on water hyacinth modified with citric acid for adsorption of methylene blue in water

Recently, textile wastewater contamination has been a common problem in Indonesia because many textile industries disposed their wastewater directly to the river without proper treatment. The purpose of this study was to investigate the ability of a low-cost adsorbent based on water hyacinth. The adsorbent is prepared from water hyacinth powder (WHP) and water hyacinth modified with citric acid (WHMCA) for removal of dyes methylene blue (MB) in water. In order to know the properties of the adsorbent, WHP and WHMCA were characterized by FTIR and SEM, respectively. The effect of dose of adsorbent (10 – 100 mg), pH condition (2 – 10), contact time (30 min – 24 h) and initial concentration of methylene blue (100 – 600 mg/L) were investigated. Based on Langmuir isotherm adsorption model, it was found that the adsorption capacity of the adsorbent before and after modification with citric acid for MB was 261 mg/g and 320 mg/g, respectively and the optimum contact time was 2 h. The finding of the present study proved that WHMCA should be considered as a promising adsorbent in the near future