DEM PARAMETERS CALIBRATION OF MIXED BIOMASS SAWDUST MODEL WITH MULTI-RESPONSE INDICATORS

Taking hybrid biomass sawdust as the material, carry out the simulation calibration experiment with JKR contact model based on DEM principle. The Plackett-Burman factorial experiment is carried out by Design-Expert for 10 related factors. Combined with the steepest climbing test scheme, according to the Box-Behnken experiment, the parameter calibration of the multi-response Indicators is completed. The results are as follows: the Poisson's ratio of hybrid sawdust is 0.30, the density is 399.22kg·m-3, the recovery coefficient between sawdust particles is 0.47, the rolling friction coefficient between sawdust particles is 0.39, and the parameter of surface energy density between sawdust particles (JKR) is 0.29J·m-2. Through the comparative verification experiment, it can be seen that the relative error of the repose angle is 3.41%, and the relative error of the stress-time response curve is less than 6.36%, which verifies the reliability of the calibration method, and provides a theoretical reference for the study of the constitutive characteristics of biomass materials and the densification mechanism.

Efficient Adsorption of Lead Ions from Synthetic Wastewater Using Agrowaste-Based Mixed Biomass (Potato Peels and Banana Peels)

The aquatic environment is continuously being polluted by heavy metals released from industrial, domestic, agricultural, and medical applications. It is difficult to remove heavy metals, as they are nonbiodegradable. Heavy metals cause genotoxicity and serious carcinogenic disorders. Various conventional methods have been used for the removal of heavy metals, but these are time-consuming and not economical, so green methods, being economical, are preferred over conventional methods. Adsorption, being effective, environmentally friendly, and cheap, is often preferred. The present investigation investigated the adsorption efficiency of agrowaste-based biosorbents for removal of Pb(II) ion from the synthetic wastewater. Mixed biomass of banana peel and potato peels was used to create biosorbents. The biosorbents were characterized in terms of structural and surface morphology by SEM, while functional groups were analyzed by FT-IR and XRD analysis. The adsorption of Pb(II) was studied by a batch method, and various experimental parameters were studied. Optimum conditions for the removal of lead were pH = 5, concentration = 10 ppm, adsorbent dosage = 1.0 g, and contact time = 2 h. Kinetic modelling studies showed that the adsorption of Pb(II) ions followed a pseudo-second-order mechanism, and the Langmuir isotherm model was found to fit well for this study. Highlights: Synthesis of biosorbents (mixed biomass of potato peel and banana peel, biochar, TiO2 nanocomposites). Characterization of prepared biosorbents (SEM, XRD, FT-IR). Optimized parameters (pH, initial concentration, adsorbent dosage, and contact time) for removal of pollutant.

Investigation of the effects of pretreatment on the elemental composition of ash derived from selected Nigerian lignocellulosic biomass

Lignocellulosic biomass is an important source of renewable energy and a potential replacement for fossil fuels. In this work, the X-ray fluorescence (XRF) method was used to analyze the elemental composition of raw and pretreated lignocellulosic biomass of cassava peels, corn cobs, rice husks, sugarcane bagasse, yam peels, and mixtures of cassava peels and yam peels, corn cobs and rice husks and all five biomass samples combined. The influence of particle size on elemental properties was investigated by screening the selected biomass into two size fractions, of an average of 300 and 435 µm, respectively. The total concentration of Mg, Al, Si, P, S, Cl, Ca, Ti, Cr, Mn, Fe, Co, Cu, Zn, Sn, Ni, Br, Mo, Ba, Hg, and Pb were determined for each of the biomass samples before and after the different pretreatments adopted in this study. From the results of the analysis, there was a significant reduction in the concentration of calcium in all the analyzed biomass after the alkaline pretreatment with rice husks biomass having the lowest concentration of 66 ppm after the alkaline pretreatment. The sulfur content of the acid pretreated biomass increased considerably which is likely due to the sulfuric acid used for the acid pretreatment. The fact that a mixture of biomass feedstock affects the properties of the biomass after pretreatment was validated in the mixed biomass of cassava peels and yam peels biomass as an example. The concentration of Mg in the mixed biomass was 1441 ppm but was 200 ppm and 353 ppm in individual cassava peels and yam peels respectively. The results of this study demonstrated that pretreated mixtures of biomass have varied elemental compositions, which could be an important factor affecting downstream processes, especially if a hybrid feedstock is used in a large-scale application.

Removal of textile azo dyes with mixed biomass of Aspergillus niger and orange peel (Citrus sinensis L. Osbeck)

This study evaluates the removal of textile dyes using mixed adsorbents prepared by the growth of Aspergillus niger in orange peels. The highest azo dye removal efficiency was obtained at pH 2, solid: liquid ratio (1: 4 g·mL-1) and time of equilibrium of 250 minutes for each dye. The concentrations of Remazol Black B (RB) and Remazol Red (RR) in both synthetic textile effluents were between 25 mg·L-1 and 100 mg·L-1. The mixed adsorbent was characterized by X-ray diffraction (XRD), spectroscopy infrared region (FTIR) and scanning electron microscopy (SEM). The results indicated that there was a 100% removal of RB and 94.85% of RR at the concentration of 25 mg·L-1. At the concentration of 100 mg·L-1, the percentages of removal reached 98.87% for RB and 96.37% for RR, respectively. The proposed mixed adsorbent was able to remove the textile dyes, presenting adsorptive capacities of 20.77 mg·g-1 and 19.28 mg·g-1 for the dyes RB and RR. Regarding the adsorption kinetics, the experimental data showed that the pseudo second order model was the one that best explained the adsorptive process. For the equilibrium results, the Langmuir model and the Langmuir-Freundlich model were the ones that best fit the experimental data of RB and RR, respectively. The mixed adsorbent produced is a promising alternative for the treatment of textile effluents.