High removal of emerging contaminants from wastewater by activated carbons derived from the shell of cashew of Para

Activated carbon from the shell of the cashew of Para (SCP) was produced by chemical activation with ZnCl using the ratio of SCP: ZnCl2 1.0:1.5 at 700 degrees C. The prepared activated carbon (SCP700) was used for the removal of two emerging contaminants, 4-bromophenol (4-BrPhOH) and 4-chloroaniline (4-ClPhNH2) that are primarily employed in the industry. Different analytical techniques were used to characterize the activated carbon. From the N-2 adsorption-desorption isotherms were obtained the specific surface area of 1520 m(2) g(-1) and total pore volume of 0.492 cm(3) g(-1). The functional groups were identified by the FTIR technique and quantified by modified Boehm titration. The results revealed the bearing of several functional groups on the SCP700 surface, which may utterly influence the removal of the emerging contaminants. The equilibrium experiments showed that the maximum uptaken capacities (Q(max)) achieved at 45 degrees C were 488.2 (4-BrPhOH) and 552.5 mg g(-1) (4-ClPhNH2). The thermodynamic parameters demonstrated that the processes of 4-BrPhOH and 4-ClPhNH2 adsorption are exothermic, spontaneous, energetically suitable, and the magnitude of Delta H degrees is compatible with physisorption. The mechanism of the adsorption of the emerging contaminants onto the carbon surface is dominated by microporous filling, hydrogen bonds, pi-stacking interactions, and other Van der Waals interactions. The use of activated carbon for the treatment of industrial synthetic wastewater with several inorganic and organic molecules commonly found in industrial effluents showed a very high percentage of uptaking (up to 98.64%).

Automated summary

Activated carbon (SCP700) produced from cashew shells was effective in removing two emerging contaminants, 4-bromophenol and 4-chloroaniline, commonly used in industry. The carbon exhibited high specific surface area and total pore volume, with diverse functional groups on the surface influencing contaminant removal. The adsorption mechanism for the contaminants involved microporous filling, hydrogen bonds, pi-stacking interactions, and Van der Waals interactions, with high uptake capacities observed in industrial synthetic wastewater treatment.