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The aim of this study was to synthesize activated carbon from low-cost material and then magnetize it with CoFe2O4 nanoparticles for evaluating its efficiency in the removal of cephalexin from aqueous media. The physical and structural properties of the synthesized adsorbent were analyzed by SEM, BET, XRD, and VSM techniques. In addition, the effect of parameters, including pH, the concentration of cephalexin, adsorbent dose, and contact time, were studied to determine the equilibrium adsorption process isotherms and kinetics. The results of this study showed that the removal efficiency of cephalexin increases with increasing contact time and adsorbent dose and decreases with increasing pH and the initial concentration of cephalexin. As the concentration of antibiotics increased from 50 to 250 mg/L, the removal efficiency of cephalexin decreased from 96.8% to 36.1%. Optimal conditions for cephalexin removal were obtained at pH = 3, time = 30 min, antibiotics concentration = 50 mg/L, and adsorbent dose = 2 g/L. Cephalexin antibiotic adsorption process follows the Freundlich isotherm (R2 = 0.9817) and pseudo second-order kinetics (R2 = 0.939). Although the removal of cephalexin increases with increasing adsorbent dose, the amount of cephalexin adsorbed per unit mass of adsorbent (qe) decreases from 27.5 to 18.3 mg/g from 0.25 to 2.5 g/L of activated carbon. The present study showed that magnetized low-cost material activated carbon, in addition to having properties such as rapid and easy separation, has a high potential for cephalexin adsorption. [ABSTRACT FROM AUTHOR]

Treatment of colored wastewater is one of the important challenges of environmental engineers. Adsorption is one of the most efficient methods in dye removal. The aim of this study was to prepare a magnetic adsorbent with Fe3O4 nanoparticles as an inexpensive adsorbent to remove basic violet 16 (BV16) dye from aqueous media. In this experimental study, the effect of parameters such as initial solution pH, adsorbent dose, initial dye concentration, and contact time on the adsorption rate was investigated. The residual dye concentration was read at 545 nm by using a spectrophotometer. Physical, surface, and magnetic properties of the adsorbent were analyzed using Brunauer–Emmett–Teller (BET), Vibrating-Sample Magnetometer (VSM), X-ray Powder Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning electron microscope (SEM) techniques. Adsorption data were described by Langmuir and Freundlich isotherms and reaction kinetics. The results showed that with increasing the contact time and increasing the adsorbent dose, the amount of dye removal by the adsorbent increased and with decreasing the initial concentration of dye, the amount of removal increased. The results also showed that with increasing pH, the removal efficiency of the process increased linearly. According to resuls, the highest BV16 dye adsorption efficiency was 99%, which was obtained at determined values of studied parameters including pH of 7, adsorbent dose: of 0.5 g/L, initial BV16 dye concentration of 25 mg/l, mixing speed of 250 rpm, and contact time of 45 min. Moreover, according to results, removal of BV16 dye using adsorption onto clinoptilolite zeolite magnetized with Fe3O4 nanoparticles obey a second-order kinetic model and Freundlich model (R2>0.99). According to SEM images, the adsorbent surface used is non-uniform and has many pores and also the morphology of the adsorbent surface is preserved after loading of Fe3O4 nanoparticles. According to VSM images, the magnetic saturation in composite is 18.11 emu/g. Results hihlighted the adsorption of BV16 dye onto clinoptilolite zeolite magnetized with Fe3O4 nanoparticles was a useful technique and could provide high efficiency in removal of studied dye from aqueous solutionsl; thus, it mabe be effective and useful in removal other similar pollutants. [ABSTRACT FROM AUTHOR]

Textile industries use large amounts of water and chemicals for finishing and dying processes. The chemical structures of dyes vary enormously, and some have complicated aromatic structures that resist degradation in conventional wastewater treatment processes because of their stability to sunlight, oxidizing agents, and microorganisms. The objective of this research is to compare the adsorption efficiency of two types of magnetic activated carbons derived from Banana peel and Salvia seed for the removal of basic blue 41 dye. The faculty of the produced activated carbons to remove basic blue 41 dye from aqueous solutions via batch adsorption has been examined under several operating conditions such as pH, adsorbent dose, initial adsorbate concentration and contact time. The cheap, non-toxic produced activated carbons (AC) were characterized by scanning electron microscope and Brunauer-Emmett-Teller analyses. The best conditions of dye adsorption with BPAC@ Fe3O4 equal to pH = 9, AC dose 0.5 g/L , dye concentration 50 mg/L and equilibrium contact time 30 min, optimal dye adsorption conditions for SSAC@Fe3O4 equal to pH = 9, adsorbent dose 0.75 mg/L , dye concentration 50 mg/L and equilibrium contact time is 30 min. This study followed the Langmuir isotherm model well with regression coefficient of R2= 0.9886 for BPAC@Fe3O4 and regression coefficient of R2= 0.9764 for SSAC@Fe3O4. [ABSTRACT FROM AUTHOR]