Hectorite-CTAB–alginate composite beads for water treatment: kinetic, isothermal and thermodynamic studies

Abstract

Encapsulation of hectorite-modified CTAB with Ca-alginate formed reusable adsorbent beads for wastewater treatment.

Anionic dye removal by immobilized bacteria into alginate-polyvinyl alcohol-bentonite matrix

“…The hydrogel was stirred using a stirrer for up to 30 min and dripped into a cold 4% w/v CaCl 2 solution using a syringe injection to form round beads [ 31 ]. The beads were immersed in CaCl 2 solution for 24 h [ 32 ] and stored in a refrigerator at 4 °C for preservation. In this study, immobilization of dead bacterial biomass was also carried out and bacteria were inactivated using high temperatures by autoclaving at 121 °C for 15 min [ 33 ].…”

The application of biosurfactant-producing bacteria immobilized in PVA/SA/bentonite bio-composite for hydrocarbon-contaminated soil bioremediation

“…Beads were formed by dripping the hydrogel solution into 4% (w/v) CaCl 2 solution (cross-linking agent) using a sterile disposable syringe. 28 The formed beads were immersed in 4% (w/v) CaCl 2 solution for 24 hours (cross-linking time). Subsequently, the beads were washed with sterile demineralized water and ready to be used.…”

Adsorption and biodegradation of the azo dye methyl orange using Ralstonia pickettii immobilized in polyvinyl alcohol (PVA)–alginate–hectorite beads (BHec-RP)

“…Hectorite-CTAB was synthesized using the method described by Asranudin. 2,3 In this synthesis, 40% CTAB was added to the LiCl : Mg(OH) 2 : SiO 2 (1.33 : 5.00 : 7.60), and the resulting mixture was subjected to calcination at 550 °C in a nitrogen environment for 1 hour. This was followed by exposure to air for 4 hours, and the calcined hectorite was mixed with PVA hydrogel, sodium alginate (SA), and R. pickettii cells.…”

“…1 Among these dyes, azo dyes (R 0 -N]N-R 00 ) constitute the dominant group, representing approximately 70% of the total colorants. 2,3 Synthetic dyes are used in various industrial sectors, including textiles, pharmaceuticals, printing, paper, food, leather, and laboratories, as indicators and stains for biological specimens. [4][5][6] The extensive use of synthetic dyes is consistent with the ease of water contamination.…”

“…This adsorbent shows biocompatibility in the PVA-alginate mixture, is non-toxic, hydrophilic, and provides large pores. 2,3,42 Therefore, hectorite can be used as the base material for bacterial cell immobilization to enhance the rate of pollutant degradation.…”