THE REMOVAL OF HEAVY-METALS BY USING AGRICULTURAL WASTES

The removal of heavy metals from wastewater using adsorbants such as w aste tea, Turkish coffee, exhausted coffee, nut and walnut shells has investigated. Batch studies were conducted at room temperature and ads orption experiments were carried out by shaking 0.3 g of adsorbent wit h 100 ml synthetic wastewater containing Cr (VI), Cd (II) and Al (III) metal ions. The remaining concentration of heavy metals in each sampl es after adsorption at various time intervals was determined spectroph otometrically. Batch studies showed that these adsorbents exhibit a go od adsorption potential for Al (III) metalions. The adsorption ratios of Al(III) were as 98, 99, 96, 99.5 and 96% for waste tea, Turkish cof fee, exhausted coffee, nut and walnut shells, respectively. These resu lts were compared with those obtained using activated carbon as adsorb ent. The batch adsorption kinetics and adsorption equilibria were exam ined and described by a first order reversible reaction and Freundlich isotherm, respectively. The first order rate and isotherm constants h ave been calculated.