The use of air-lift adsorber with a floating filling from a cross-linked chitosan hydrogels for Reactive Black 5 removal

Tomasz Jóźwiak,Urszula Filipkowska

doi:10.1038/s41598-021-92856-y

Tomasz Jóźwiak, Urszula Filipkowska

Open Access

https://doi.org/10.1038/s41598-021-92856-y

Copy DOI

Journal: Scientific Reports	Publication Date: Jun 28, 2021
Citations: 5	License type: open-access

Affiliation: University of Warmia and Mazury in Olsztyn

Abstract

This work substantially extends knowledge on the possibilities of treating colored industrial wastewater via sorption under flow conditions. The presented study aimed to determine the effectiveness of Reactive Black 5 (RB5) dye sorption from aqueous solutions under dynamic (flow) conditions in an unconventional air-lift type loop reactor with a filling made of hydrogel chitosan sorbents. The dye was removed from mono-component solutions (deionized water + RB5) and synthetic dyeing wastewater containing RB5 dye, NaCl (3 g/L), and an anti-creasing agent—UNICREASE JET (2 g/L). The sorbents tested in the study included: unmodified chitosan (CHs), chitosan ionically cross-linked with sodium citrate (CHs-CIT), and chitosan covalently cross-linked with epichlorohydrin (CHs-ECH). Each experimental series aimed to determine: the bed break-through time (CE = 0.1 C0), time of depletion of the sorbent’s sorption properties (CE = C0), and maximal sorption capacity of the sorbents (Qmax). The data obtained under dynamic conditions were described using Thomas, Yoon–Nelson, and Bohart–Adams models. The volume of the solution effectively treated in the air-lift reactor was significantly affected by chitosan sorbent type. At C0 = 50 mg RB5/L, the adsorber with the filling made of 1 g d.m. CHs allowed for the effective treatment of 4.6 L of synthetic wastewater (Qmax = 1504.7 mg/g), whereas CHs-ECH ensured 34.6 L of the treated solution (Qmax = 3212.9 mg/g).

Highlights

This work substantially extends knowledge on the possibilities of treating colored industrial wastewater via sorption under flow conditions
The experimental data obtained for Reactive Black 5 (RB5) sorption from S1 and S2 solutions onto CHs, cross-linked with sodium citrate (CHs-CIT), and CHs-ECH under flow conditions in the air-lift type adsorber were described using three popular sorption models: Thomas, Yoon–Nelson, and Bohart–Adams
The ionic cross-linking of chitosan using sodium citrate ensured sorbent stability under the flow conditions at pH 4, whereas its covalent cross-linking with epichlorohydrin made the sorbent stable at pH 3

Summary

Introduction

This work substantially extends knowledge on the possibilities of treating colored industrial wastewater via sorption under flow conditions. At C0 = 50 mg RB5/L, the adsorber with the filling made of 1 g d.m. CHs allowed for the effective treatment of 4.6 L of synthetic wastewater (Qmax = 1504.7 mg/g), whereas CHs-ECH ensured 34.6 L of the treated solution (Qmax = 3212.9 mg/g). CHs allowed for the effective treatment of 4.6 L of synthetic wastewater (Qmax = 1504.7 mg/g), whereas CHs-ECH ensured 34.6 L of the treated solution (Qmax = 3212.9 mg/g) Several industrial activities, such as textile, tanning, and paper industries, generate the colored wastewater. The advantage of chitosan in this form is the convenience of its application and removal from the solution after the treatment process This is especially useful in adsorbers with a floating filling. The hydrogel form of chitosan enables easy modification of the sorbent, e.g. cross-linking

Objectives

Methods

Results

Conclusion