Abstract:In order to promote the comprehensive utilization of rice bran resources, the extraction method and adsorption characteristics of Pb2+ of rice bran insoluble dietary fiber were studied. In this paper, enzyme-chemical method was used to extract insoluble dietary fiber from defatted rice bran. The single factor and orthogonal experiments were used to study the effects of high-temperature amylase addition, NaOH mass fraction, alkaline hydrolysis time, and alkaline hydrolysis temperature on the extraction rate and purity of the product, and the optimal preparation parameter of rice bran insoluble dietary fiber was determined. The results showed that when the high-temperature amylase was added at 0.3%, with the 3% NaOH mass fraction and the alkaline hydrolysis at 75 ℃ for 75 min. The purity and yield of the obtained product was 85.74% and 37.40% respectively. Furthermore, adsorption experiments revealed that when the extract was shaken in a 20 mg/L Pb2+ aqueous solution for 180 minutes, and the adsorption rate was 96.67%. The kinetics was in line with the pseudo-second-order kinetic equation. It could better describe the binding behavior between rice bran insoluble dietary fiber and Cd2+, and there existed chemical adsorption during the adsorption process. The rmodynamic investigations had found that: 25 ℃ was more conducive to the adsorption process. This process was entropy-driven and spontaneous. At the same time, the adsorption ability of Pb2+ was weak, predicting that the applied force was mainly physical adsorption. Therefore, rice bran insoluble dietary fiber had a better ability to adsorb Pb2+. This test provides a theoretical basis for the extraction conditions of rice bran dietary fiber material and its Pb2+ adsorption characteristics.