The Equilibrium, Kinetics, and Thermodynamics Studies of the Sorption of Methylene Blue from Aqueous Solution Using Pulverized Raw Macadamia Nut Shells.

Joshua N Edokpayi,Ahmed Adetoro,Samson O Alayande,John O Odiyo

doi:10.1155/2020/8840666

Abstract

In this study, the potential for pulverized raw macadamia nut shell (MNS) for the sequestration of methylene blue from aqueous media was assessed. The sorbent was characterized using scanning electron microscopy for surface morphology, functional group analysis was performed with a Fourier-transform infrared spectrometer (FT-IR), and Brunauer–Emmett–Teller (BET) isotherm was used for surface area elucidation. The effects of contact time, sorbent dosage, particle size, pH, and change in a solution matrix were studied. Equilibrium data were fitted using Temkin, Langmuir, and Freundlich adsorption isotherm models. The sorption kinetics was studied using the Lagergren pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. The feasibility of the study was established from the thermodynamic studies. A surface area of 2.763 m2/g was obtained. The equilibrium and kinetics of sorption was best described by the Langmuir and the pseudo-second-order models, respectively. The sorption process was spontaneous (−ΔG0=28.72 − 31.77 kJ/mol) and endothermic in nature (ΔH0=17.45 kJ/mol). The positive value of ΔS0 (0.15 kJ/molK) implies increased randomness of the sorbate molecules at the surface of the sorbent. This study presents sustainable management of wastewater using MNS as a potential low-cost sorbent for dye decontamination from aqueous solution.

Highlights

Freshwater resources are increasingly under threat from pollution due to anthropogenic activities
Freshwater is unevenly distributed across the globe, it remains a major resource for livelihood and economic growth. e threat to freshwater quality is majorly caused by human activities and lifestyles. e discharge of untreated and partially treated wastewater remains a major point source of surface water pollution [1]. e impact of polluting freshwater includes loss of source of livelihood, undue stress to aquatic organisms, and negative impacts on the environment [2, 3]
No study has reported the use of the raw natural product for the decontamination of methylene blue. us, this study investigated the impact of change in water chemistry on the sorption of methylene blue onto raw pulverized MNS. is study is, aimed at evaluating the potential of South African macadamia nut shell for decontamination of hazardous dye from aqueous solution; the force needed to break the nut shell is reported

Summary

Introduction

Freshwater resources are increasingly under threat from pollution due to anthropogenic activities. E impact of polluting freshwater includes loss of source of livelihood, undue stress to aquatic organisms, and negative impacts on the environment [2, 3]. Few authors have reported on the methods of making activated carbon from macadamia nut shell (MNS) [15,16,17]. Few reports have investigated the use of activated carbon from MNS for hexachromium removal [16], tetracycline removal [18] phenol removal [19], and reactive dyes [20]. Is study is, aimed at evaluating the potential of South African macadamia nut shell for decontamination of hazardous dye from aqueous solution; the force needed to break the nut shell is reported No study has reported the use of the raw natural product for the decontamination of methylene blue. us, this study investigated the impact of change in water chemistry on the sorption of methylene blue onto raw pulverized MNS. is study is, aimed at evaluating the potential of South African macadamia nut shell for decontamination of hazardous dye from aqueous solution; the force needed to break the nut shell is reported

Materials and Method

Batch Equilibrium

Results obtained