Locally available agroresidues as potential sorbents: modelling, column studies and scale-up

Arth Jayesh Shah,Bhavin Soni,Sanjib Kumar Karmee

doi:10.1186/s40643-021-00387-1

Arth Jayesh Shah, Bhavin Soni + Show 1 more

Open Access

https://doi.org/10.1186/s40643-021-00387-1

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Abstract

Sawdust, cotton stalk and groundnut shell were used for removal of methylene blue from aqueous solution using batch sorption. Effect of initial dye concentration, temperature, and particle size of sorbents on methylene blue removal was investigated. Sorption capacity increases with rise in initial dye concentration and temperature. Impact of particle size on sorption of methylene blue was investigated and indicated that removal of dye increases with decrease in particle size of sorbents. Maximum sorption for sawdust, cotton stalks and groundnut shell were 9.22 mg g−1, 8.37 mg g−1 and 8.20 mg g−1 respectively; at 60 °C and 100 ppm initial dye concentration. Sorption isotherms were analyzed using fundamental Freundlich isotherm. Subsequently, sips isotherm model was employed for better fitting. Kinetic study shows that, biosorption process is pseudo-second-order in nature. During the course of this study, adsorption dynamics revealed that film diffusion was key step for biosorption. In addition, thermodynamics of sorption was studied; and it was found that Gibbs free energy (∆G°) decreases with increase in temperature. Sawdust was found to be best among all the sorbents. Therefore, column studies and breakthrough curve modelling were performed using sawdust. Furthermore, it was estimated that a scaled-up column using sawdust can treat 6672 L of wastewater in 24 h with 80% efficiency.

Highlights

Stringent norms are laid down by monitoring and control authorities for chemical process industries (CPIs) for releasing effluents into the environment
With increase of the initial dye concentration (C0) driving force acting on dye molecules moving towards sorbent increases and it can overcome resistance offered by the film
Increase in initial dye concentration will lead to better occupancy of active sites which might be empty at low dye concentrations

Summary

Introduction

Stringent norms are laid down by monitoring and control authorities for chemical process industries (CPIs) for releasing effluents into the environment. There is an urgent need to develop technologies/processes for waste removal using low cost and readily available sorbents Along this line, search for effective low-cost sorbents which can have similar effect as that of activated carbon became area of research for many researchers. Search for effective low-cost sorbents which can have similar effect as that of activated carbon became area of research for many researchers In this regard, cotton stalks, cotton waste, cotton dust (Ertaş et al 2010), sawdust (Garg et al 2004; Azlina et al 2013), orange peel (Namasivayam et al 1996), banana peel (Annadurai et al 2002), wood (Asfour et al 1985; Ho and McKay 1998), bagasse pith (Nassar and El‐Geundi 1991), chitosan (Sakkayawong et al 2005), and algae biochar (Chen et al 2020a; Tan et al 2020) are a few low-cost sorbents previously reported for dye removal and pollution control

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