Search

This research investigated an up-draft gasification system of paper waste sludge (PWS) to generate syngas. Lower heating value (LHV) and cold gas efficiency (CGE) are influenced by PWS moisture content and equivalence ratio (ER). Supply air for gasification by increasing ER reduced LHV due to increased inert gas (N2) content. PWS moisture provides steam for the water-gas shift reaction that increases LHV and CGE. But the moisture of the PWS higher than 15 % significantly reduced the gasification temperature (less than 800 ?), causing the overall gasification efficiency to decrease. According to the response surface methodology (RSM) using Design Expert software, the optimum conditions were predicted that PWS moisture of 11.09 %, ER of 0.104, syngas produced with an LHV of 10.48 MJ/kg, and a CGE of 67.55 %. Experimenting with a real model has similar results with small differences compared to the RSM model in the same conditions. Syngas from the real model has an LHV of 10.22 ± 0.24 MJ/kg and a CGE of 65.68 ± 1.02 %. PWS gasification under optimal conditions is an effective PWS treatment method that not only solves PWS but can also generate energy in the form of syngas.

This study investigates the sulfuric acid hydrolysis process to improve the efficiency of paper waste sludge (PWS) hydrolysis in a paper recycling plant. The Response Surface Methodology (RSM) was used to evaluate the influence of factors, including liquid-to-solid ratio, acid concentration, temperature, and time on the hydrolysis process. The optimal conditions for hydrolysis were determined to be a solid-to-liquid ratio of 1/30.15, an acid concentration of 8.17 wt%, at a temperature of 91.31 ?, and a reaction time of 6.15 h, which yielded the highest sugar content of 11.12 g.L-1 (with the hydrolysis efficiency of 61.4 %). The resulting sugar solution was then fermented by Acetobacter xylinum bacteria to produce bacterial cellulose (BC) layers. This study addresses the environmental organic pollution caused by PWS and transforms it into a more valuable form with high carbon content and purity, such as BC.

This context presents the study of ultrasonic-assisted extraction (UAE) to obtain phenolic and flavonoid compounds from watermelon rind powder (WRP). The antioxidant activity of the extracts was investigated using DPPH and ABTS+ assays. One-factor experiments were conducted to examine the effect of each factor (solid-to-liquid ratio (SLR), acetone concentration (AC), temperature, and time) on the UAE of WRP. Box-Behnken Design (BDD) model was employed to optimize the UAE conditions based on total phenolic contents (TPC), total flavonoid content (TFC), and their antioxidant activities. The optimal conditions were 1:30.50 SLR, 70.71% AC, 29.78 °C, and 10.65 min extraction time. There were no significant differences between predicted and experimental results (less than 6.0%), recommending a feasible and innovative process of deploying UAE to extract phenolics and flavonoids effectively from watermelon rind.

In this study, the gasification of rice husk in a downdraft process is simulated by Aspen Plus software to predict an appropriate operation condition for designing small-scale equipment. Gibbs models of the reactions occurring in the process are applied for the simulation while tuning the equivalence ratio (ER) to forecast the syngas’ compositions. Based on the analysis, ER value of 0.096 is selected to generate a syngas mixture consisting of CO (43.26 mol%), CH4 (0.09 mol%), and H2 (33.87 mol%), corresponding to the optimal calorific value of 8.92 MJ/kg and efficiency of 86.98 %. A real experiment is performed with the small-scale gasifier to evaluate the results obtained from the simulation. The pilot results show that not only the input air flow rate but other confounding factors also affect the combustion efficiency at some degree, which is compatible with the simulation model. The total energy value acquired from the conversion of 5.0 kg of dry rice husk was 86.82 MJ, while the energy value of the syngas obtained was 44.42 MJ syngas.

This research presented a method to synthesize magnetic nanocrystalline cellulose-based nanocomposites using in-situ co-precipitation technique to produce ferromagnetic oxide particles (Fe3O4) that were grafted on the surface of cellulose nanocrystals (CNCs). The synthesized material was used to remove lead ions from aqueous solutions. Different physicochemical analyst techniques such as XRD, FTIR, SEM, and TEM were used to characterize the structure of the material upon the different ratios of cellulose nanocrystals/ Fe3O4. The XRD analysis showed that CNC/Fe3O4 nanocomposite has characteristic diffraction peaks corresponding to Fe3O4 and cellulose nanocrystals. The FTIR spectrum indicated the specific functional groups of Fe3O4 and CNC in the nanocomposite materials. The size of nanoparticles produced in this work were less than 15 nm with Fe3O4 and roughly 25 nm with CNC via image SEM and TEM. According to these studies, with the same Pb2+ concentration in water of 200 ppm, the best condition for homogenous materials was the 1:1 ratio (cellulose nanocrystals: Fe3O4) and the absorption capacity at time balance (qe) was 0.1132 mg/g. The lead adsorption of material was evaluated by the ICP-OES measurement method. The equilibrium data fitted the Freundlich isotherm model better than the Langmuir isotherm model. The new adsorbent can help removing 60 % of Pb2+ from the solution and can be magnetically separated from the continuous phase.

This research presented a method to synthesize magnetic nanocrystalline cellulose-based nanocomposites using in-situ co-precipitation technique to produce ferromagnetic oxide particles (Fe3O4) that were grafted on the surface of cellulose nanocrystals (CNCs). The synthesized material was used to remove lead ions from aqueous solutions. Different physicochemical analyst techniques such as XRD, FTIR, SEM, and TEM were used to characterize the structure of the material upon the different ratios of cellulose nanocrystals/Fe3O4. The XRD analysis showed that CNC/Fe3O4 nanocomposite has characteristic diffraction peaks corresponding to Fe3O4 and cellulose nanocrystals. The FTIR spectrum indicated the specific functional groups of Fe3O4 and CNC in the nanocomposite materials. The size of nanoparticles produced in this work were less than 15 nm with Fe3O4 and roughly 25 nm with CNC via image SEM and TEM. According to these studies, with the same Pb2+ concentration in water of 200 ppm, the best condition for homogenous materials was the 1:1 ratio (cellulose nanocrystals: Fe3O4) and the absorption capacity at time balance (qe) was 0.1132 mg/g. The lead adsorption of material was evaluated by the ICP-OES measurement method. The equilibrium data fitted the Freundlich isotherm model better than the Langmuir isotherm model. The new adsorbent can help removing 60 % of Pb2+ from the solution and can be magnetically separated from the continuous phase. [ABSTRACT FROM AUTHOR]