Sugarcane bagasse powder as biosorbent for reactive red 120 removals from aqueous solution

Production of eco composites based on natural rubber and recycled sugarcane bagasse waste to be utilised as a type of food contact

Natural fibres are abundant, renewable, and biodegradable, which has inspired numerous academics worldwide to investigate their possible applications in various industrial fields. The food packaging sector is seeking bio-based and biodegradable substitutes to increase sustainability. In this study, new composites were prepared from natural rubber (NR) and sugarcane bagasse fibres (SCB) with different concentrations of SCB (0, 2.5, 5, 10 &20 phr). The effect of SCB on the properties of natural rubber was studied before and after the alkaline treatment of the fibres. The biocomposites are characterized using Fourier transmission infrared spectroscopy, thermogravimetric analysis, scanning electron microscope, transmission electron microscope, and dielectric measurements in addition to rheological and mechanical analysis. The overall migration test for biocomposites loaded with 20phr SCB was performed to assess the biocomposite's safety as food contact materials. The study's results indicated that, adding SCB improved the conductivity, tensile strength, and elongation at break of natural rubber. Alkaline treatment strengthened the bonding between the filler and matrix and improved biocomposites' thermal dielectric and mechanical properties. The overall migration test indicated that the alkaline treatment increased the overall migration to simulants. Accordingly, alkaline-treated NR-SCB biocomposites are effective eco-friendly food packaging candidates for certain types of food such as aqueous non-acidic products.

Isotherms, kinetics and thermodynamics of industrial dye acid red 27 adsorption on Sugarcane Bagasse Ash

In this study, sugarcane bagasse ash (SCBA), obtained as residue from the sugar mill, was used as an adsorbent for Acid Red 27 (AR27) removal from aqueous solutions. The ash characterization data showed 23.63% of organic compounds and silica (α-SiO2) as the most expressive inorganic compound (confirmed by X-ray diffractogram), the BET surface area had a value of 62.79 m2.g-1 and the pHpzc was 8.45. Regarding the adsorptive tests, the optimal initial pH to the dye removal was 2.0. The adsorption equilibrium reached in about 4 h contact time and optimum SCBA dosage was found to be 4 g.L-1. The pseudo-second order model best represented the adsorption kinetics. The Freundlich equation presented the best fit to the equilibrium data for the removal of AR27 by ash, with maximum adsorption capacity of 15 mg.g-1 at pH 2.0. Thermodynamic study indicate that AR27 adsorption on SCBA occurs through a physisorption mechanism, with ΔHºads < 15 kJ.mol-1. The ΔHºads evaluated by Vant' Hoff equation was explained as a combination of water desorption enthalpy, ΔHºW and isosteric like enthalpy, ΔHºD for the dye adsorption in liquid environment. The ΔHºD = 9.2 kJ.mol-1 was calculated from Clausius-Clapeyron approach. The effects of coexisting anions on the adsorption and regeneration and reuse of the adsorbent were also investigated. This study suggests that SCBA, which was used without any pretreatment, has the potential to be applied as a low-cost adsorbent to mitigate effluents contamination with AR27 dye at low concentrations.

Modified Beaded Materials from Recycled Wastes of Bagasse and Bagasse Fly Ash with Iron(III) Oxide-Hydroxide and Zinc Oxide for the Removal of Reactive Blue 4 Dye in Aqueous Solution

Dye contamination in wastewater affects the photosynthesis of aquatic plants and algae by blocking the sunlight, and it induces toxicity to aquatic organisms, which might result in human health effects. Thus, the treatment of dyes in wastewater is required before discharging into the receiving water for safety purposes. Six dye adsorbent materials bagasse beads (BB), bagasse fly ash beads (BFB), bagasse beads with mixed iron(III) oxide-hydroxide (BBF), bagasse fly ash beads with mixed iron(III) oxide-hydroxide (BFBF), bagasse beads with mixed zinc oxide (BBZ), and bagasse fly ash beads with mixed zinc oxide (BFBZ) were synthesized and investigated using various characterization techniques such as X-ray diffractometry (XRD), field emission scanning electron microscopy with focused ion beam (FESEM-FIB), energy dispersive X-ray spectrometry (EDX), and Fourier transform infrared spectroscopy (FTIR). A series of batch experiments on the effects of dosage (0.5-3 g), contact time (3-18 h), temperature (30-80°C), pH (3-11), and initial concentration (30-90 mg/L) were used to investigate reactive blue 4 (RB4) dye removal efficiencies in aqueous solution, and their adsorption isotherms and kinetics were studied for explaining their adsorption patterns and mechanisms. All dye adsorbent materials demonstrated semicrystalline structures, and their surface morphologies had a spherical shape with coarse surfaces. Five main elements of oxygen, carbon, calcium, chlorine, and sodium and six main functional groups of alcohol and carboxylic acid (O-H), carbon dioxide (O=C=O), aromatic groups (C=O and N=O), alkene (C-H), and sodium alginate (C-O-C) were detected in all dye adsorbent materials. For batch tests, they could remove RB4 dye by more than 90%, and BFBF exhibited the highest RB4 dye removal efficiency at 99.36%. Freundlich and pseudo-second-order kinetic models well explained their adsorption patterns and mechanisms, in which BFBF demonstrated a higher maximum adsorption capacity (q _m) of 10.277 mg/g than that of other dye adsorbent materials. Therefore, all dye adsorbent materials offer good potential for further industrial applications.

Mathematical modeling and numerical simulation of sulfamethoxazole adsorption onto sugarcane bagasse in a fixed-bed column

Having rigorous mathematical models is essential for the design and scaling of adsorption columns. In this study, the dynamic behavior of the sulfamethoxazole adsorption on sugarcane bagasse was studied and compared using analytical models and a theoretical mechanistic model. Initially, fixed-bed column tests were carried out at different flow rates and bed heights. Then, the experimental data were fitted with the most widely used analytical kinetic models, and their fit and fixed-bed parameters were compared with the mechanistic model. Of all analytical models analyzed, the Log-Gompertz model was the one that had the best agreed with experimental data. Although some analytical models fitted the experimental data accurately, their usefulness was questionable. Their parameters did not show a clear relationship with the change in operating conditions, and in certain cases had different behavior from that observed in experimentation. Conversely, the mechanistic model not only predicted the breakthrough curves with great accuracy in the initial and transition stage (R² > 0.92; SSE < 0.06), but it also estimated relevant parameters. Additionally, the effects of the global mass transfer coefficient (K_i) and the axial dispersion coefficient (D_z) on breakthrough curves were studied using the mechanistic model. Increasing K_i increased the slope of the breakthrough curves with a faster adsorption rate. Similarly, high values of D_z produced lower adsorption capacities of the adsorbent; and it was established that the axial dispersion is relevant in SMX adsorption on SB. The theoretical model presented can be used for the design, scaling, and optimization of adsorption columns.