On the Suitability of Almond Shells for the Manufacture of a Natural Low-Cost Bioadsorbent to Remove Brilliant Green: Kinetics and Equilibrium Isotherms Study.

R Melhaoui,A Elamrani,N Tijani,C Hano,S Lairini,N Houmy,Y Miyah,M Abid,S Kodad,A Mihamou,H Serghini-Caid,M Addi

doi:10.1155/2021/6659902

Abstract

Almond production generates a large number of coproducts, but the farmer's interest mainly focuses on the nutritional and commercial aspects of the kernel for getting the best return from their harvests. Thus, almond coproducts such as almond shells that represent more than 70% of biomass remain underexplored. In this work, the suitability of almond shell powder (ASP) as a natural low-cost adsorbent was evaluated in the adsorption of brilliant green dye (BG), which is known as a chemical pollutant. Brunauer–Emmett–Teller (BET) method, for the determination of specific surface area, Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) techniques were performed to characterize the ASP adsorbent. The batch adsorption kinetic study for the removal of BG dye was carried out by varying pH, temperature, initial concentration of the dye, bioadsorbent dose, and contact time. It was found that 98% of BG dye is removed under the following optimal experimental conditions: ASP bioadsorbent dose of 1 g/L at T = 25°C, pH = 6.8, and C0 = 1 g/L, which proves that ASP can be used as an excellent low-cost bioadsorbent for the removal of BG dye from wastewater. The experimental isotherm data were analyzed using Freundlich and Langmuir models. The results show the best correlation with single-layer adsorption, and the adsorption kinetics seems to follow a pseudo-second-order model.

Highlights

Industrial pollution is a major factor causing the degradation of the environment
almond shell powder (ASP) that was used in this work comes from two French varieties, Ferragnes and Ferraduel, which are the most cultivated in the eastern region of France. e first step in the preparation of the ASP sample was the collection of the almond in the different study orchards. e second step was to shell the almond fruits, which are washed several times with distilled water until pH becomes stable in order to remove dust and other inorganic impurities. e obtained shell was dried in the oven for 24 hours at 60°C
Ese results show a porous structure of the analyzed ASP sample. e scanning electron microscopy (SEM) confirms this result and allows us to characterize the surface morphology of the ASP as seen in Figure 3, which indicates that the ASP sample was composed of irregular pores. e images obtained show cellulose fiber of various forms and sizes, similar to those observed by SEM analysis of cellulose extracted from almond ASP [31]]. ese results show that the morphology of ASP is characterized by a high porosity, which may provide more contact sites to adsorb the synthetic dyes and heavy metals

Summary

Introduction

Industrial pollution is a major factor causing the degradation of the environment. Water pollution caused by industrial effluents threatens biological life in aquatic systems; its impact on human health is no longer to be demonstrated and becomes a worrying problem to consider before it is too late. The textile industry produces colored toxic effluents, which are generally resistant to destruction by biological treatment methods [6]. Brilliant green (BG) is a typical example of toxic cationic dye extensively used in textile dyeing and paper printing [7], with harmful effects on humans. It may cause dermatitis upon skin contact and irritations to both e Scientific World Journal the gastrointestinal and respiratory tracts in humans, resulting in a cough and shortness of breath [8, 9]. Erefore, adsorption with low-cost adsorbents seems to be an effective and economic method for industrial effluent treatment. In eastern Morocco, many farm cooperatives are gathered into economic interest groups (EIGs). ey are faced with the valorization challenges of almonds and their coproducts

Objectives

Methods

Results