Carboxylic acid functionalized sesame straw: A sustainable cost-effective bioadsorbent with superior dye adsorption
Yanfang Feng1, Yang Liu2, Lihong Xue3
1Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Agro-Environment in Downstream of Yangtze Plain, Ministry of Agriculture, Nanjing 210014, China; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA.
Abstract:
This study prepared a carboxylic functionalized bioadsorbent that met the "4-E" criteria: Efficient, Economical, Environmentally friendly, and Easily-produced. Sesame straw (Sesamum indicum L.) was functionalized through treatment with citric acid (SSCA) and tartaric acid (SSTA). The products were examined for adsorption capacity and mechanisms. Langmuir model gave the best fit for the isotherm data, and the maximum monolayer adsorption capacity of SSCA was 650mgg-1 for methylene blue (MB). The excellent dye adsorption capacity of SSCA can be attributed to the introduction of ester groups during citric-acid modification and the tube-like structures (i.e., sesame straw cell wall remnants). At last, the cost of carboxylic acid functionalized bioadsorbents was evaluated, which showed that SSCA would be the most cost-effective bioadsorbent. Additionally, this study presents a thermo-decomposition methodology for contaminant-loaded bioadsorbent. Results showed that SSCA is probably one of the few bioadsorbents that can be produced and applied in industrial scale.
