Sodium Alginate-Based Composite Films for Effective Removal of Congo Red and Coralene Dark Red 2B Dyes: Kinetic, Isotherm and Thermodynamic Analysis

Abstract

The present study aimed to investigate the adsorption capacity of two anionic dyes, namely, Congored (CR) and Coralene Dark Red2B (DR), onto prepared alginate (Alg) and chitosan(Cs) biopolymer films. The two biopolymers were combined at different mass ratios using a “solvent-cast” process to incorporate their unique properties and evaluate their effectiveness in removing the dyes. All samples were characterized by means of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and determination of point of zero charge (pHpzc). The swelling ratios were determined by gravimetric measurements. The effects of pH, adsorption time, thickness, temperature and initial concentration of CR and DR dyes on the adsorption results were studied systematically. The dye adsorption kinetics showed that the Alg/Cs films at % proportions of 75/25, 50/50, 25/75 and 0/100 reached equilibrium from 30 min to 180 min with high removal efficiencies that varied between 222.30 mg/g and 842.36 mg/g. The adsorption mechanism of CR and DR onto the synthesized biofilms was confirmed through Langmuir isotherm and the kinetics fitted well by the pseudo-second-order model, suggesting a monolayer and chemisorption process. The thermodynamic results demonstrated the spontaneity and the feasibility of the process as well as the exothermic nature. Hence, the findings revealed that the Alg/Cs biofilms could be employed as potential natural adsorbents for the removal of anionic dye pollutants from aqueous environments.

Biocomposite Material Based on Lactococcus lactis sp. Immobilized in Natural Polymer Matrix for Pharmaceutical Removal from Aqueous Media

“…On the contrary, in another study [82], the authors demonstrate that the Alizarin Red S dye adsorption on Aspergillus terreus/ sodium alginate composite beads was well explained by the Langmuir isotherm. Another study conducted for the removal of congo red and coralene dark red 2B dyes from aqueous solutions by adsorption on sodium alginate-based composite films established that the adsorption mechanism was confirmed through the Langmuir isotherm [83].…”

Formation of self-nitrogen-doping activated carbon from Fish/sawdust/ZnCl2 by hydrothermal and pyrolysis for toxic chromium adsorption from wastewater

“…To study the attraction and repulsion forces between adsorbent and adsorbate during the removal process, the pH of pH PZC should be studied. The approach outlined in the literature was used to obtain the pH PZC 3 , 35 , 36 . In brief, in 100 mL flasks, 50 mg of NDAC600 was taken in 50 mL of 0.1 M NaNO 3 solutions.…”

“…Recently, through the twentieth century, the requirement for pure water is becoming challenging, and the awareness to protect our environment from pollution has developed. In particular, the growth of contamination by inorganic micro-pollutants such as heavy metals attracted the concern of many researchers because they are persistent, very toxic and sometimes have a deadly effect 3 .…”

A Review of the Strategic Use of Sodium Alginate Polymer in the Immobilization of Microorganisms for Water Recycling

“…Microorganism immobilization has been used to address various pollution issues; for example, its use has been reported for the removal of nutrients [ 56 , 68 ], organic compounds [ 119 ], microplastics [ 4 ], p-nitrophenol [ 10 , 118 ], heavy metals [ 120 , 121 ], antibiotics [ 122 ], other pharmaceutical products [ 39 , 48 ], toxins [ 72 ], textile dyes [ 123 , 124 ], and petroleum [ 17 , 125 ], among others [ 25 ]. These studies have presented interesting results, suggesting the high efficiency of IMs in water treatment.…”