A novel brick made from clay brick waste/rice husk ash/cement to adsorb heavy metals and organic dyes in wastewater

We propose a composite brick made of rice husk ash, brick waste and cement for convenient application of the adsorbent and removal (after the adsorption is completed). Four commonly found adsorbates in industrial wastewater effluents (i.e., Pb(II), As(V), Hg(II) and Malachite green dye (MG)) were selected and the adsorption studies were conducted at 25°CC. Results indicate that the brick is capable of removing 9S.S6%, 7S.36%, 22.20% and 99.9S% of Pb(II), As(V), Hg(II) and MG, respectively. These values are close to individual removal percentages by rice husk ash and clay brick and clay brick waste. The equilibrium loading follows the order Pb(II) > As(V) > MG $\approx$ Hg(II). Further, Pb(II), As(V) and MG follow the pseudo second order kinetics and the film diffusion becomes the rate-limiting step. The strength of the adsorption bond follows the order Pb(II) > As(V) >MG and the adsorption rate decreases according to MG > As(V) >Pb(II) order. Considering its adsorption efficiency and effectiveness, the proposed brick can be identified as an efficient, effective and convenient solution to treat industrial wastewater streams.