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BACKGROUND: In the present work, Hg (II) is considered as one of the most dangerous elements being released excessively into the environment from various sources. Therefore, the aim of this study is the removal of Hg (II) from wastewater effluent by synthesizing a magnetic chitosan modified with glutaraldehyde (MCS-GA) as an adsorbent. The composite structure was characterized using SEM/EDAX, FTIR, and XRD techniques. The adsorbent was tested by a batch system to determine the optimum conditions for removing Hg (II) under real conditions. RESULTS: The results showed that 0.5% GA effectively enhanced the removal efficiency. The maximum adsorption capacity of MCS-GA was 96 mg g −1 at pH 5.0 and 25 ∘ C. The adsorption isotherm data obeyed the Langmuir model (R 2 >0.981) and pseudo-second-order (R 2 >0.996) kinetic models. It was also found that Hg (II) adsorption on MCS-GA is inherently exothermic and occurs spontaneously. The reusability of MCS-GA was approved over 12 sequential cycles of adsorption-desorption. ANOVA analysis showed that the contact time has a synergistic effect on Hg (II) removal, whereas pH and initial concentration have antagonistic effects. CONCLUSION: Overall, the synthesized adsorbent was able to remove Hg (II) efficiently under both experimental and real conditions.

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A green synthesis approach was conducted to prepare amine-functionalized bio-graphene (AFBG) as an efficient and low cost adsorbent that can be obtained from agricultural wastes. In this study, bio-graphene was successfully used to remove Ciprofloxacin (CIP) from synthetic solutions. The efficacy of adsorbent as a function of operating variables (i.e. pH, time, AFBG dose and CIP concentration) was described by a polynomial model. A optimal99.3% experimental removal was achieved by adjusting the mixing time, AFBG dose, pH and CIP concentration to 58.16, 0.99, 7.47, and 52.9, respectively. Kinetic model revealed that CIP diffusion into the internal layers of AFBG controls the rate of the process. Furthermore, the sorption process was in monolayer with a maximum monolayer capacity of 172.6 mg/g. Adsorption also found to be favored under higher CIP concentrations. The thermodynamic parameters (ΔG˚<0, ΔH˚>0, and ΔS˚>0) demonstrated that the process is endothermic and spontaneous in nature. The regeneration study showed that the AFBG could simply regenerated without significant lost in adsorption capacity.