Abstract
This work develops a methodology for selective removal of industrial dyes from wastewaters using adsorption technology based on magnetic adsorbents. The magnetic nanoparticles embedded within a matrix of activated carbon were tested as adsorbents for removal of industrial dyes from aqueous solutions. The effects of four independent variables, solution pH, initial concentration of pollutant, adsorbent dose, contact time, and their interactions on the adsorption capacity of the nanocomposite were investigated in order to optimize the process. The removal efficiency of pollutants depends on solution pH and increases with increasing the carbon content, with initial concentration of the pollutants, the temperature, and the dose of magnetite/carbon nanocomposites. Pseudo-second-order kinetic model was fitted to the kinetic data, and adsorption isotherm analysis and thermodynamics were used to elucidate the adsorption mechanism. The maximum adsorption capacities were 223.82 mg g−1 for Nylosan Blue, 114.68 mg g−1 for Chromazurol S, and 286.91 mg g−1 for Basic Red 2. The regeneration and reuse of the sorbent were evaluated in seven adsorption/desorption cycles. The optimum conditions obtained for individual adsorption were selected as starting conditions for simultaneous adsorption of dyes. In binary systems, in normal conditions, selectivity decreases in the order: Red Basic 2 > Nylosan Blue > Chromazurol S.
Highlights
Progress of various industries from the past decade led to a drastic increase in industrial effluent discharge, causing dramatically environmental pollution as well as serious life-threatening problems for environment
The structure and morphology of the Magnetite/carbon nanocomposites (MNC) nanocomposites were investigated by X-ray diffraction (XRD), FTIR spectroscopy, scanning electron microscopy- (SEM-) energy dispersive X-ray (EDX), thermal analysis, and N2 adsorptiondesorption technique
As the mass ratio of activated carbon increases, the BET surfaces increased from 360 m2/g to 814 m2/g (Table 1) which is closed to activated carbon specific surface area
Summary
Progress of various industries from the past decade led to a drastic increase in industrial effluent discharge, causing dramatically environmental pollution as well as serious life-threatening problems for environment. More than 10,000 tons of dyes are used in different industries, and approximately 100 tons are released into water streams, annually. Their concentration in wastewaters usually varies from 10 to 200 mg L−1 [1]. Release of industrial effluent without proper and prior treatment into the environment is one of the major causes leading to a burden of healthcare issues worldwide. Adsorption process provides an attractive alternative for the treatment of colored wastewaters due to its simplicity, selectivity, and efficiency [2,3,4,5]
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