Influence of Initial pH Value on the Adsorption of Reactive Black 5 Dye on Powdered Activated Carbon: Kinetics, Mechanisms, and Thermodynamics

Abstract

The aim of this work was to investigate the influence of initial pH value (pH0) on the isothermal adsorption of Reactive Black 5 (RB5) dye on commercial powdered activated carbon. Four initial pH values were chosen for this experiment: pH0 = 2.00, 4.00, 8.00, and 10.00. In order to investigate the mechanism of adsorption kinetic, studies have been performed using pseudo-first-order and pseudo-second-order kinetic models as well as an intraparticle diffusion model. In addition, thermodynamic parameters of adsorption were determined for pH0 = 4.00. Results of this research showed that the initial pH value significantly influences the adsorption of RB5 dye onto activated carbon. The highest adsorption capacities (qe) and efficiencies of decolouration were observed for initial pH values of pH0 = 2.00 (qe = 246.0 mg g−1) and 10.00 (qe = 239.1 mg g−1) due to strong electrostatic interactions and attractive π···π interactions, respectively. It was also shown that the adsorption of RB5 dye on activated carbon at all initial pH values is kinetically controlled, assuming a pseudo-second-order model, and that intraparticle diffusion is not the only process that influences on the adsorption rate.

Accessible Eco-Friendly Method for Wastewater Removal of the Azo Dye Reactive Black 5 by Reusable Protonated Chitosan-Deep Eutectic Solvent Beads

“…Other adsorbents were reported to reach similar capacities, such as macadamia nutshell chemically activated and converted to magnetic mesoporous carbon (123.51 mg/g) [51], and higher adsorption capacities, when comparing our value at 298.16 K: commercial powdered activated carbon (193 mg/g, pH 4) [58], chitosan/polyamide nanofibers (205.2 mg/g, 298 K), cellulose crosslinked with polyethyleneimine and magnetic nanoparticles (330 mg/g) [59], and polyethylene terephtalate (PET) waste bottles as substrate for titanium dioxide films (155.04 mg/g) [60]. At higher temperatures, our adsorbent even surpassed these efficiencies towards RB5, with q m values of 379.9 mg/g at 318.16 K.…”

Optimising decolourization and nitrogen component properties of corn protein hydrolysate: impact of activated carbon dosage and pH

“…Shifting pH from 2.0 to 8.0 resulted in a decrease in decolourization rates of the enzymatic hydrolysate from 78.01 ± 0.34% to 35.64 ± 0.96% with 0.5% activated carbon addition, and from 89.19 ± 0.14% to 62.99 ± 1.30% with 1.5% activated carbon treatment ( P < 0.05) (calculated through eqn 1). Activated carbon exhibits enhanced adsorption of colour‐producing substances in the corn protein hydrolysate under acidic conditions, possibly attributable to its increased affinity toward these substances in the enzyme hydrolysate under such conditions (Deng et al ., 2018; Vojnović et al ., 2022). Ozsoy & Leeuwen (2010) highlighted that the most effective pH levels for removing food colorants in fruit candy waste fall within the range of 2.5–3.5.…”

Ofloxacin Removal from Aqueous Media by Means of Magnetoactive Electrospun Fibrous Adsorbents

“…pH is one of the most important parameters that govern adsorption efficiency [ 55 , 56 , 57 , 58 ]. In the present study, solution pH may have strongly affected the membranes’ removal efficiency, since OFL possesses several functional groups that are influenced by pH.…”