Tea waste/CuFe 2 O 4 (TW/C) composite was prepared by co-precipitation method. The TW and TW/C samples are characterized by FTIR, XRD, SEM and N 2 physical adsorption. The results showed that specific surface area of 350 and 570 m 2 ·g −1 for TW and TW/C, respectively. The average pore size of TW/C is ca. 100 nm. Adsorption of methylen blue onto TW/C composite has been studied. Measurements are performed at various contact time, pH and adsorbent dosage. The adsorption kinetics of methylen blue (MB) could be described by the pseudo-second order kinetic model. The adsorption isotherms are described by means of Langmuir and Freundlich isotherms. It was found that the Freundlich model fit better than the Langmuir model. The thermodynamic constants of the adsorption were calculated to predict the nature of adsorption. The values of thermodynamic parameters indicate that a spontaneous and endothermic process was occurred.

Activated carbon developed from agricultural waste orange peel (COP) was prepared. COP was characterized using Fourier infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and BET. COP has surface area and mean pore diameter of 225.6 m2 g−1and 22.40 nm, respectively. The removal of violet B (VB) and violet 5R (V5R) from aqueous solutions by COP was investigated. The effect of operational parameters such as contact time, pH, initial dye concentration, and adsorbent dosage on the adsorption of dyes was investigated. Maximum dye was removed within 30 min of contact time at pH > 7. Two common models, the Langmuir and Freundlich isotherms, were used to investigate the interaction of dye and COPs. The isotherm evaluations revealed that the Langmuir model provides better fit to the experimental data than the Freundlich model. The adsorption of VB and V5R onto COP was followed by pseudo-second-order kinetic model with a good correlation (R2>0.99). Activation energies 5.47 and 29.7 KJ mol−1were determined for violet B and violet 5R, respectively. The rate of adsorption of violet 5R was faster than that of violet B (kV5R>kVB). The prepared COP could thus be used as promising adsorbent for removal of organic dyes, especially azo dye, from polluted water. The solid COP could be conveniently regenerated after adsorption.

Linde Type-A (LTA) zeolite was prepared from sodium aluminate and sodium metasilicate by hydrothermal process precursors. Sodium metasilicate prepared from molten NaOH and SiO₂. The zeolite was characterized by FTIR, XRD, XRF and SEM. The adsorption of Fe(III) from aqueous solution by zeolite A was studied. Different parameters like contact time, pH and concentration of iron were investigated. The results show that at contact time of 60 min and pH of 6 maximum adsorption of iron onto zeolite was observed. The kinetic data was analyzed using pseudo-first-order and pseudo-second-order kinetic models. The adsorption kinetics of Fe(III) were fitted well with the pseudo-second-order kinetic model.

The effect of copper doping on the cobalt ferrite was investigated. Ceramic, pigment, nanoparticles of composition, Cu x Co 1-x Al 2 O 4 (x = 0.0-1), were prepared using a chemical co-precipitation method. The effect of calcination temperature on the structure of the materials was investigated at 200, 500, 900 and 1200 • C. The ceramic pigments were characterized by XRD, FTIR, TEM, UV-vis and colorimetric methods. The XRD patterns displayed the characteristic peaks of the spinel structure and cubic unit cell. The XRD results at 200, 500, 900 and 1200 • C showed that the cobalt spinel phase formed at 500 • C. The FTIR spectra displayed vibrations which were ascribed to the spinel structure. Particle sizes were determined by TEM to be 140 nm and 70 nm for CoAl 2 O 4 and Cu 0.5 Co 0.5 Al 2 O 4 , respectively. The UV-vis spectra had three bands attributed to the Co 2+ spin transitions in tetrahedral sites. The calorimetric data confirm the formation of sky blue pigments with highly negative b* values.