Kinetic modelling of p-Nitrophenol ions adsorption onto activated and non- activated carbon from macadamia nutshells in a model solution

Abstract

Water contamination caused due to organic pollutants has been a significant issue because they have a tendency to build up within the organism to hazardous concentrations. Additionally, they are often resistant to degradation and, as a result, persist in the environment for prolonged periods. Among the most common phenol derivatives is P-Nitrophenol (PNP), which is one of the most common and toxic pollutants found in wastewater. The present study investigates the potential of utilizing activated carbon derived from macadamia nut shell as an effective means of addressing the presence of P-Nitrophenol (PNP) in wastewater, aiming at its remediation. To introduce, the nutshell underwent charring in a blast furnace operating at a temperature of 600°C. The resulting ash was subsequently activated and employed for the purpose of adsorbing PNP from an aqueous solution. The activated and non-activated adsorbents were employed in order to examine the kinetics of PNP ion binding from a homogenous water solution, utilizing a lot of experimental setup. Sorption behaviour of PNP ions on both unmodified and modified sorbents was assessed using spectrophotometric measurements. Subsequent analysis was performed to analyse the obtained data, with approximate first-order kinetics and second order kinetics. The correlation coefficients (R2

) provided strong evidence the complete set of experimental conditions conformed to the Pseudo-second-order kinetic model, with R2 figures above 0.9851. This finding explained how adsorption process of PNP ions involved a chemisorption mechanism. The modified adsorbent demonstrated higher experimental and calculated adsorption capacities compared to the unmodified adsorbent. Specifically, the modified adsorbent exhibited higher values when it came to the adsorption of PNP ions. The rate constants (k2) values were found elevated in the chemically altered adsorbent compared to the unaltered adsorbent. Among the PNP ions, the highest rate constant recorded was 5.130 ×10 1

(mg g -1min 1

). The findings of the study demonstrated the effectiveness of the adsorbents in removing PNP from wastewater. This promising approach holds the potential to mitigate pollution in the environment resulting from industrial activities, while also offering an economically and environmentally friendly solution.