Removal of As(V) and Cr(VI) with Low-Cost Novel Virgin and Iron-Impregnated Banana Peduncle-Activated Carbons

Abstract

This work reports the investigation of activated carbons from virgin banana peduncle (ZR1) and iron-impregnated banana peduncle (ZR2) as adsorbents for the removal of As(V) and Cr(VI) ions from aqueous solutions. Both adsorbents were characterized through the point of zero charge, powder X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray, Brunauer–Emmett–Teller, and Fourier transform infrared spectroscopic techniques. The effects of initial pH, contact time, temperature, and initial concentration on metal ion adsorption were investigated. Adsorbents existed as both crystalline and amorphous species having homogeneous surface cavities and surface area of 749.73 and 369.66 m2/g for ZR1 and ZR2, respectively. The maximum As(V) removal of 79.32 and 69.08% was obtained using ZR1 and ZR2, respectively, whereas the maximum Cr(VI) removal was calculated as 69.73% for ZR1 and 73.78% for ZR2. Kinetic modeling data were found to be best fitted for the pseudo-second-order reaction, and rate constants were calculated. The theoretical adsorption capacities (q m) of ZR1 and ZR2 were calculated through Langmuir and Freundlich models. The maximum As(V) adsorption capacities calculated for ZR1 and ZR2 were 13.33 and 9.066 mg/g, respectively, whereas the maximum Cr(VI) adsorption capacity for both was 13.26 mg/g at 298–328 K. The reaction was endothermic with decreased randomness at the solid–liquid interface due to positive entropy and enthalpy values. All kinetic and thermodynamic parameters showed the feasibility of the adsorption process, and characterization after adsorption indicated ZR1 and ZR2 novel activated carbons as efficient and cheapest biosorbents for removing As(V) and Cr(VI).

Actual Adsorptive Efficiency of Aqueous Cr(VI) Using Modified Banana Pseudostems

“…With the majority of cellulose (30.8%), hemicellulose (27.8%), and lignin (6.1%), banana pseudostems can be modified to become an effective adsorbent for heavy metals from aqueous medium [11]. Banana wastes (e.g., fruit peels, pseudostems, trunks, stalks, and leaves) have been modified by various chemical methods for effective Cr(VI) removal from polluted solution and industrial wastewater [12]- [14]. To define the adsorption efficiency, all most studies have used UV-Vis spectrophotometer with 1,5diphenylcarbazide as complexing compound for Cr(VI) in acidic medium [12], [13], [15].…”

Physical Characteristics, Blue-Green Band Emission and Photocatalytic Activity of Au-Decorated ZnO Quantum Dots-Based Thick Films Prepared Using the Doctor Blade Technique

“…As such, the degradation of such pollutants has become the need of the hour. Photocatalysis quickly degrades the organic pollutants and converts them into harmless and nonhazardous products [ 11 , 12 ]. Due to rising urbanization and industrialization, water adulteration has developed as a global problem in water refinement.…”