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Coir pith obtained from the coir industry as waste biomass was used to prepare activated carbon by chemical activation using phosphoric acid (H 3 PO 4 ). The influences of activation temperature and lasting time of activation on specific surface areas (SSA) of the activated carbons were observed. Physical characteristics of the activated carbon were investigated using X-ray diffraction (XRD), infrared spectroscopy (IR), surface area analyzer, scanning electron microscopy (SEM), thermal analysis and potentiometric titration. The feasibility of using activated carbon for the removal of phenol (P), p-chlorophenol (PCP) and pnitrophenol (PNP) from water and petroleum refinery industry effluents was investigated. The effects of contact time, adsorbent dose, ionic strength and initial concentration on the adsorption of phenols onto the activated carbon were investigated. The optimum pH for the maximum removal of phenols was 6.0. The equilibrium adsorption data of phenols were correlated to Langmuir and Freundlich isotherm models, the latter being the best fit of the experimental data. Dynamics of the sorption process and mass transfer were investigated using McKay and Urano-Tachikawa models. Adsorption kinetic data fits the Urano-Tachikawa kinetic model. The utility of the adsorbent was tested by using petroleum refinery industry effluent. The adsorbed phenols can be recovered by treatment with 0.1 M NaOH solution.

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This paper describes the adsorption properties of Cu(II) ions from aqueous media by 4-ethyl thiosemicarbazide (ETSC) intercalated organophilic calcined hydrotalcite (OHTC). Elemental analysis, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric–differential thermogravimetric (TG/DTG) studies have helped in characterizing the adsorbent. The effects of various factors like adsorbent dose, pH, initial concentration, and contact time were studied. The pH study indicated that Cu(II) has a good adsorption potential at pH 5.5. The adsorption of metal ion remained constant after 4 h. The pseudo-second-order model was the best fit to describe the adsorption kinetics. The FTIR spectroscopy revealed that both amino and thiocarbonyl groups in ETSC–OHTC are responsible for Cu(II) removal. The Freundlich model described the adsorption results very well, and the K F value was found to be 21.38 at 303 K. Electroplating industry wastewater was used to test the adsorption efficiency toward Cu(II) removal. The recovery (∼95.0 %) of Cu(II) ion from the loaded adsorbent was possible with 0.01 mol·kg–1 HCl solutions. Many successive adsorption/desorption cycles were achieved without any noticeable change in the adsorption capacity.

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