Study On Removal Of Heavy Metals In Water With Tea Residue

Two modified adsorbents aimed at the removal of Zinc,Copper and Chromium ion in drinking water were prepared from tea residue.Microwave heating and hydrogen peroxide immersion were designed as the two modification methods.Nine factors influencing adsorption effects of the adsorbent were studied,including the heating time,the heating power for microwave heating modified adsorbent,the immersion time,the immersion temperature,the hydrogen peroxide concentration for hydrogen peroxide immersion modified adsorbent,and the time,pH,the temperature,the quantity of the tea residue of water treatment by modified adsorbent.The results indicated that the optimum conditions of preparation were microwave heating time 9 min,microwave heating power 700 W.Using microwave heating modified adsorbent,the optimum condition of water treatment were 120 min,80?,dosing tea residue 20 g/L,the optimum pH is 8 on the adsorption of Zn(?)and Cr(?),and 7 on the adsorption of Cu(?).Under the optimum condition,the maximum removal rates of Zn(?),Cu(?),and Cr(?)was 98.58%,97.93%,99.02%,respectively,which made the concentration of these ion in purified water qualified by national standards GB 5749-2006 for drinking water.The optimal treatment condition was explored,apart from that,the adsorption mechanism of the single-component solution containing Zinc and Copper ion at the temperature range of 25? to 40? by using tea residue adsorbent was also explored.The results indicated that the removal of Zinc and Copper ion is part of chemical adsorption.By comparing Langmuir adsorption model and Freundlich adsorption model,it is foundthat the process conform to Freundlich adsorption isothermal equation well.The method has the advantage of simple raw meterials and easy operation,meanwhile,the tea residue adsorbent is green and environmently friendly,which provides a new way to purify the waste water containing heavy metal ions.