Study on Biosorption Performance of Cd(Ⅱ) in Waste Water by Modified Mulberry Leaves

Abstract

Mulberry leavesare rich in plant polyphenol and flavonoid.Amounts of hydroxyl and hydroxyl functional groups are distributed on the surface, which can be absorbed with heavy metal ions by complexation and electrostatical processes.However, there are commonly soluable tannic in organisms and it is not suitable to use organisms to remove Cd from waste water.In this study, mulberry leaves were used as the experimental materials and were boiled and modified with 1 mol/L H3PO4 to prepare an adsorbent for cadmium.Results show that the absorption effect of modified mulberry leaves to Cd(Ⅱ) is best when pH is 4.0.When the initial concentration of Cd is 150 mg/L, 6 g/L modified mulberry leaves have absorption recovery of 96.58%.The adsorption process of modified mulberry leaves to Cd(Ⅱ) adheres to the pseudo-second order equation.The isothermal adsorption process of cadmium with modified mulberry leaves fits the Langmuir model well.Maximum absorption capacity of Cd(Ⅱ) on the chemically modified mulberry leaf absorbent is 30.58 mg/g, which is higher than that of a previous study.The modified mulberry leaves are easily available, which provides a new method for Cd removal from waste water.

Keywords

• mulberry leaves
• chemical modification
• waste water
• cadmium
• biosorption