Papers by Keyword: Pretreatment

Abstract: Oil palm processing produces more than 70-wt% of its lignocellulosic content as by-product, the bulk of which is empty fruit bunches (EFB). EFB contains cellulose, hemicellulose, and lignin which makes it a potential source of bio-based chemicals. This research explores the utilization of ethanol as a potentially green, sustainable, and low-cost organic solvent (organosolv) for EFB fractionation. Organosolv processes target extraction of lignin (delignification). Conventional delignification use an acid hydrolysis process with lignin yields of approximately 18-wt%. In this study the EFB was treated in 2 stages, (1) soaking EFB for 1 hour followed by (2) delignification using ethanol as the organic solvent under variable process conditions. Temperature (140°C, 170°C), liquid-to-solid ratio (L/S-w/w) (6:1, 15:1), and wt%-ethanol (20-wt%, 50-wt%) were varied while residence time was constant at 30 minutes (experiments were run in duplicate). Data analysis using 2k Factorial Design Method showed the significant variables were temperature, L/S-ratio, wt%-ethanol, interaction of L/S ratio and temperature, temperature and %wt-ethanol interaction, and L/S-ratio and %wt-ethanol. The optimum operating conditions (170°C, 15:1, 20wt%-ethanol) produced a lignin yield of up to 31%wt. This preliminary study shows ethanol in an organosolv process is a potential delignification option.

Abstract: Necessity for reduction of greenhouse gases emissions, the growing demand for improvement of biorefinery technologies and the development of new biorefining concepts, oblige us as a society, mainly scientists, to develop novel biorefinery approaches. The aim of this research was to comprehensively characterize lignocellulosic biomass that was obtained after 2-furaldehyde production, in terms of further valorization of this resource. This research shows that birch wood chips can be used in the new biorefinery processing chain for production of 2-furaldehyde, acetic acid and subsequent cellulose pulp obtaining, using thermomechanical and alkaline peroxide mechanical pulping process. In addition, obtained lignocellulosic residue was also characterized. Unique bench-scale reactor system was used to obtain a lignocellulosic material without pentoses and with maximum preservation of cellulose fiber for further use. Studies on the deacetylation and dehydration of birch wood hemicelluloses of pentose monosaccharides to 2-furaldehyde and acetic acid using orthophosphoric acid as a catalyst were carried out. Results showed that depending on the used pretreatment conditions the 2-furaldehyde yield was from 0.04 to 10.84 % o.d.m., the acetic acid yield was from 0.51 to 6.50 % o.d.m. and the lignocellulose residue yield was from 68.13 to 98.07 % o.d.m. with minimal content of admixtures. In addition, experimentally the optimal 2-furaldehyde production conditions regarding to purity and usability of cellulose in leftover of lignocellulosic material were developed. Best results in terms of both 2-furaldehyde yield and purity of residual lignocellulose were obtained in experiment where catalyst concentration was 70%, catalyst amount 4 wt.%, reaction temperature 175 °C and treatment time 60 min. By performing alkaline peroxide mechanical pulping of the relevant LC residue, it was possible to obtain pulp with tensile index comparable to standard printing paper, indicating that it is possible to perform stepwise 2-furaldehyde production with subsequent pulping to obtain various value added products.

Abstract: Reverse Osmosis (RO) Brine is waste generated from the desalination process using the RO method. RO Brine is generally directly thrown back into the sea, even though it has the potential to be reprocessed because it still contains a variety of ions in it. The best method in RO Brine processing is Electrodialysis. But it has a problem of decreased membrane performance caused by the formation of fouling. The fouling problem can be overcome by doing a pretreatment process to eliminate impurities contained in RO Brine, one of which is Ca²⁺. The existence of Ca²⁺ can trigger the formation of CaSO₄ deposits. Therefore, it needs excess reagent Na2CO3 with a certain amount to eliminate the whole Ca²⁺. Currently, it isn’t yet known the best pretreatment conditions that can eliminate impurities ions and produce high concentrations of NaCl. Pretreatment trials are needed in various variations of reagents amount to reduce impurities. The purpose of this study is to find out the best RO Brine pretreatment process that will later be used for the electrodialysis process to produce high NaCl recovery. The best results were obtained in the pretreatment process with variations NaOH excesses by 15% and Na₂CO₃ by 30% from the ideal stoichiometry.

Abstract: An automobile company in this research faced the consistency problem from the chemical concentration in degreasing bath which was one of the stages in the pretreatment process. The problem came from the proportion of total alkaline (T.Al) lower than the lower control limit (LCL) which was set at 18.2 points during February – May 2020. This resulted in the low values of Cp and Cpk, i.e. 0.83 and 0.51, respectively. To remedy the problem, Six Sigma (DMAIC) was applied to improve the process stability. The cause and effect matrix was used to analyse the potential causes of problems and prioritise the causes to solve. It was found that four (causes) factors were solved by auto titration and feeding controller installation to reduce variance and increase stability. Another one factor, quality of water, was improved by adding a check item to monitor and collect data during the initial implementation stage. The result after improvement showed that Cp and Cpk were increased to 1.82 and 1.52 in August 2020, respectively.

Abstract: Jet grading technology is an efficient process in different industries. In this research, tungsten powder with different particle size distribution was used as a raw material to produce tungsten products via isostatic pressing as well as sintering. The mechanism of jet grading and the morphology and particle size distribution of different precursors were analyzed. The results showed that jet grading technology had remarkable effect on tungsten powder classification. The appropriate grading treatment was helpful to the formation of tungsten products with high performance. After jet grading and the following process like pressing and sintering, the tungsten products with better properties were manufactured which was used fischer particle size of 3.0~3.5μm as the raw material. The obtained products’ density was 18.77g/cm³ and its hardness was 372.15HV_0.3.

Abstract: Carbon steel is widely used in the industry due to its mechanical properties and low cost, but in contrast it resists poorly to corrosion, leading to economic losses and mechanical issues. The use of surface treatment is essential to extend the life of the metallic material. In this context, niobium is being studied for its great corrosion resistance properties. The aim of this paper was to produce and evaluate the corrosion protection of a niobium-based coating produced by the Pechini Method. The resin was applied in the metallic surface by dip-coating and then calcinated at 450 oC for 1 hour. The coated material was analyzed electrochemically by open circuit potential and potentiodynamic polarization, and morphologically by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The electrochemical analyses showed that the deposition of the coating increased the corrosion resistance and the morphological analyses indicated a homogenous coating with the presence of phases of NbO and NbO₂.

Abstract: Natural Organic Matter (NOM) content in peat water is a major problem of membrane fouling in ultrafiltration (UF). For that, two stages adsorption as pre-treatment was employed to minimize the membrane fouling of NOM content. This research was carried out to investigate the effect of two stages adsorption on ultrafiltration performance for NOM removal that remains in peat water. This method was using powdered activated carbon (PAC) dosage of 80, 160, 240, 320, 400, 480, 560, 640, 720, 800, 880 dan 960 mg.L^-1. Then, Polysulfone (Psf) material was employed for Ultra filtration process. Membrane was applied in a dead-end mode with various operating pressure (1; 1.5; 2; 2.5; 3 bar). As a results, the optimum dose of PAC was 800 mg L-1 with dosage ratio of 3/4:1/4. Two stages adsorption-UF PSf provided the range from 86.9 to 92.8% of KMnO₄ and 74.1-88.1% of UV₂₅₄. For the experimental condition of 3 bar, the highest flux was achieved up to 39.919 L h^-1.m^-2.

Abstract: Basing on the study of adsorption behavior of glycidoxypropyl-trimethoxy-silane (GTMS), pretreatment method of AA2024-T3 aluminum alloy for sol-gel films was optimized. The morphology, composition and corrosion protective performance of alloy coated with the films were investigated by using FE-SEM, EDS, AFM and EIS. The results showed that the Al matrix exhibited better ability to adsorb GTMS molecules than the second phase particles, especially at lower concentration of GTMS. Further, the 5% GTMS films cover the whole surface, but the selective adsorption behaviors still exist. It was concluded that less second phase particles and smoother surface were benefit to the sol-gel films on aluminum alloy. Depending on this conclusion, the pretreatment method for sol-gel films was optimized. The optimized surface condition conducted with 50 g•L^-1 sodium hydroxide and ultrasound at 60 oC for 30 s was obtained. These samples coated with the sol-gel films revealed good anti-corrosion performance. The coverage degree of the films was up to 97.95 %.

Abstract: Plasma technology provides an effective way to modify the surface of polymeric materials and thus improve the physicochemical properties of this material. This study was a preliminary study in exploring the application of plasma technology in the surface modification of silk fiber. Experimental results revealed that the dyeability of silk fabric with acid dye was improved after plasma treatment.

Abstract: The objective of this study was to characterize the performance of lignocellulosic biomass (LCB) to assess its use as a potential bioethanol or biofuels through pretreatment process. The pretreatment process was performed to remove crystalline structural of biomasses in order to improve enzymatic hydrolysis process. In this work, combined electron beam irradiation and ionic liquid method was used as the pretreatment process for various LCBs such as Gigantochloa albociliata (GA), Leucaena leucocephala (LL), oil palm frond (OPF), acacia and microcrystalline cellulose (MCC) as reference. Irradiation dose was measured through electron beam accelerator over a range of 100-1000 kGy. Ionic liquid (IL) is known as green solvent that can dissolve cellulose. 50% v/v 1-ethyl-3-methylimidazolium acetate (EMIMAc) IL was employed to enhance the effect of irradiation in pretreatment process. The LCBs was analyzed by using two method; Fourier transform infrared (FTIR) and X-ray diffraction (XRD). FTIR result shows different pattern of spectra and peak for each condition. Lateral order index (LOI) based on Beer’s Law was also calculated to determine the changes in structure order after pretretament. For XRD results, the crystallinity index (CrI) of pretreated LCBs was calculated by using Segal’s Equation in order to determine the pattern based on different conditions. The highest percentage of effectiveness showed by pretreated Acacia as the values of LOI and CrI is the lowest compared to other LCBs which is 41.77% and 25.21%, respectively.