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A magnetic ion exchange resin was tested for the removal of Cr(VI) ions from aqueous solutions in a batch reactor at different resin dosages (0.5-1.5 g L -1 ), pH values (2-10), temperatures (25 o C-55 o C) and initial concentrations of Cr(VI) (0.11 -2.12 mmol L -1 or 5.7-110 mg L -1 ). The experimental data were evaluated using kinetic models based on the rate controlling steps relevant to pseudo-first order or pseudo-second order reactions or diffusion through fluid film or pores of the MIEX resin beads. Fast uptake of Cr(VI) ions by MIEX resin facilitates the attainment of equilibrium within 60 minutes. The sorption process is strongly dependent on the initial pH of the solution with maximum occurring at pH 4-6. The sorption of Cr(VI) at equilibrium increases with the increase in initial concentration according to the Langmuir isotherm, with a maximum sorption capacity of 93 mg g -1 on MIEX resin.Relatively low activation energy of 43 kJ mol -1 at a high initial concentration of 1 mmol L -1 Cr(VI) suggests a mixed chemical-diffusion controlled process, supported by the agreement of the sorption results with the homogeneous particle diffusion model with a film diffusivity of D f = 1 × 10 -9 m 2 s -1 and a pore diffusivity of D p = 8 × 10 -13 m 2 s -1 .

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The silver (Ag) powder was synthesised in a mechano-chemical (MC) process by inducing a solid-state displacement reaction between silver chloride (AgCl) and copper (Cu). The AgCl and Cu were ground in atmosphere conditions using a planetary ball mill. The reaction caused the mixture of AgCl and Cu to change the composition of the mixture, such as Ag and copper chloride (CuCl). CuCl was separated from MC product by leaching with ammonium hydroxide and we obtained Ag powder as the final product. Moreover, ascorbic acid (C 6 H 8 O 6) was used as the additive to improve dispersion of Ag powder during MC process. The ground powders, formed in the presence of additive, were characterised by X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD determined that the reaction between AgCl and Cu was complete in almost all the experiments carried out. SEM examinations revealed that the size of the particles in the synthesised metallic Ag powder was in the range of 30-300 nm.