High-activity mesoporous carbons were prepared from wild almond shells and coir pith by phosphoric acid activation and applied for adsorption of the dyes, C.I. Reactive Red 2 and C.I. Reactive Yellow 145A. The BET surface areas of these activated carbons were found to be 1133.25 and 1210.58 m 2 /g, respectively. The equilibrium data were best described by the Langmuir isotherm in all the cases. The maximum dye adsorption capacity shown by the activated carbon produced from coir pith was 2022.9 mg/g for C.I. Reactive Red 2 and 1694.3 mg/g for C.I. Reactive Yellow 145A at 60°C with initial concentration of 1000 mg/L. Pseudo-second-order kinetic model gave a good fit, with the intraparticle diffusion being one of the essential rate-controlling steps. Thermodynamic analysis revealed that the adsorption of both the dyes on activated carbons was spontaneous and endothermic in nature. The t test analysis showed that the difference between adsorption capacities of the produced activated carbons was not significant at 95 % confidence level at all the temperatures studied.

Pb (II) is extensively used by various industries and the wastewater generated is hazardous to the environment. In the present study, efficiency of a cheap adsorbent in the form of activated carbon, developed from waste biomass for the Pb (II) adsorption is investigated. With BET surface area 1133.25 m 2 /g and the pore volume 1.41 cm 3 /g, its adsorption capacity for Pb (II) was found to be 823.1 mg/g, at an initial pH of 6.0. The adsorption was best described by the Langmuir isotherm, suggesting monolayer adsorption and was favorable. The adsorption followed second order kinetics, indicating chemisorption of Pb (II), mainly by ion exchange. The adsorption was controlled by the intraparticle diffusion with significant contribution of the film diffusion. With 0.5 g/L of adsorbent dosage, complete removal of Pb (II) ions was achieved from battery industry wastewater, making it safe discharge in water bodies.

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