Bagasse-based adsorbent with nitric acid esterification and Fe(iii) chelation for the highly efficient removal of low concentration phosphate from water

Abstract

A waste material, bagasse, recovered from the sugarcane industry, was used for designing a high-efficiency phosphate adsorbent. Eutrophication is one of the most serious problems afflicting people throughout the world, so the adsorption of low-concentration phosphate from water by the innovation of a bagasse-based adsorbent is important for a greener environment. In this work, the bagasse was esterified with nitric acid and then Fe³⁺ was chelated to design Fe(III)-complexed bagasse. FTIR, XPS, ζ potential analysis and SEM were used to characterize this adsorbent. The analyzed results showed that the binding site for phosphate adsorption is the iron atom. SEM pictures explained that the adsorbent had a stable structure during the adsorption. The kinetic and isotherm adsorption experiments followed pseudo-second-order kinetics and the Langmuir model, respectively. The results of both the characterizations and the adsorption experiments demonstrated that the phosphate was adsorbed onto Fe(III)-complexed bagasse by the coordinate linkage between phosphate and the iron element on Fe-CB. This study suggested that bagasse waste could be designed as high value-added adsorbent materials to adsorb eutrophic ions such as phosphate in water.