Chitosan-coated sour cherry kernel shell beads: an adsorbent for removal of Cr(VI) from acidic solutions

Türkan Altun

doi:10.1186/s40543-019-0172-6

Abstract

In this study, a composite biosorbent in the form of beads was produced from chitosan and the powder of sour cherry kernel shells. Characterization of chitosan-coated sour cherry kernel shell beads was done using elemental analysis, FT-IR spectroscopy, SEM, and EDX spectrum analysis. Adsorption capacity of chitosan-coated sour cherry kernel shell beads was tested in removal of Cr(VI) under different conditions, pH 2.0–7.0, adsorbent dosage 0.01–0.20 g, initial Cr(VI) ion concentration 10–315 mg L−1, temperature 25–55 °C, and contact time 0–240 min, and compared to that of uncoated sour cherry kernel shell powder. Cr(VI) adsorption was highly dependent on the solution pH, and the maximum Cr(VI) adsorption was achieved at pH 2.03 at 25 °C in 45 min. The adsorption data was applied to Langmuir, Freundlich, Scatchard, and Dubinin-Radushkevich (D-R) adsorption isotherm models. According to the Langmuir isotherm model, the adsorption capacity of chitosan-coated sour cherry kernel shell beads was found higher than that of uncoated sour cherry kernel shell powder, 24.492 and 13.57 mg g− 1. The study demonstrated that chitosan-coated sour cherry kernel shell beads can be used for Cr(VI) removal from acidic aqueous solutions.Graphical abstract

Highlights

Designing adsorbents from low-cost and abundant biological waste materials has attracted attention in recent years (Mohan and Pittman Jr 2006)
The band appearing at 1728 cm−1 can be attributed to the carbonyl groups of kernel shell. This band was observed in the spectrum of coated sour cherry kernel shell beads (C-SCKS) beads, but it did not appear in the spectrum of Cr(VI)-adsorbed C-SCKS beads
Following the adsorption of Cr(VI), the bands in the spectrum of C-SCKS were shifted to higher wavenumbers

Summary

Introduction

Designing adsorbents from low-cost and abundant biological waste materials has attracted attention in recent years (Mohan and Pittman Jr 2006). Biopolymers are considered to be an abundant, renewable, biodegradable, and low-cost source of material for the production of adsorbents. These properties make adsorbents with biological origins much more attractive than synthetic adsorbents (Wang and Chen 2009). Chitin is obtained from, for example, waste of crabs in food processing industry using simple acidic, alkaline, and depigmentation treatments. It is converted into chitosan, a more versatile derivative, through deacetylation procedure

Methods

Results

Conclusion