Papers by Keyword: Hydrolysis

Abstract: Starch is the most important polysaccharide and has become the major component of many food industries as well as textile, paper, cosmetic and certain industries that engage in adhesive, thickening, stiffening and gelling agents. However, native starch has limited function and therefore is recommended to modify its physical and chemical properties to meet the consumers’ needs. In this study, the native starch was chemically modified to determine its behavior and characteristics after using hydrolysis process of acid hydrolysis method. There were three types of starch that has been studied - potato, cassava and corn. These starches undergone hydrolysis process using hydrochloric acid and their characteristics were determinedthrough moisture absorption test and Fourier Transform Infrared Spectroscopy (FT-IR) analysis. For moisture absorption test, hydrolyzed starch tends to absorb more surrounding moisture than native starch. This behavior resulted from the increase of hydrophilic character of starch after being modified. The FT-IR analysis shows that hydrolyzed starch content got more hydroxyl group than the native starch due to the breakdown of hydrogen bond between the starch molecules after the acid hydrochloric treatment.

Abstract: Sugar is very important raw material of many industries such as food, beverage and renewable energy. In this research, pretreatment and hydrolysis of agricultural wastes to produce reducing sugars for an ethanol production were investigated. The rice stalk and corn stover from agricultural wastes were firstly pretreated with sodium hydroxide at 121 °C in different time as 20 30 and 40 minutes for removal of lignin. After that, the condition of hydrolysis using sulfuric acid of the pretreated rice stalk and corn stover was optimized. The optimum condition that obtained the highest reducing sugar content from rice stalk and corn stover of 76.12 and 136.25 mg/ml were using 1.0 % v/v sulfuric acid at temperature of 121 °C for a hydrolysis time of 40 minutes. This research made value adding in the industrial processing, decrease environmental problem and reduce global warming crisis by optimized utilization of agricultural waste.

Abstract: The aim of this study was to study the morphology and structural characteristic of NCC hydrolyzed from filter paper. The NCCs were extracted by acid hydrolysis at 50°C for 1 hour, using 55% conc. H₂SO₄ under vigorous mechanical stirring, centrifugation at 12000 rpm in distillate water and followed by homogenizing at 7000 rpm. The morphology and surface profiles of the NCC suspension was characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The crystalline structure of the NCC was evaluated by using X-ray diffraction (XRD) technique. As a result, hydrolysed NCC was found to have a rod liked shape with diameter in the range of 100-300nm length and 10-50nm width, with the aspect ratio value of 10.3 nm. According to XRD investigations, the semi-crystalline cellulose was observed with the presence of an amorphous broad hump and crystalline peaks at 2θ of 15^o and 22.7^o, respectively. The crystalinity index of the raw filter paper was calculated as 86.7 % and increased to 94.4 % as it was extracted to NCC. Crystallite size of raw filter paper and NCC was calculated as 20.6 nm and 11.4 nm, respectively

Abstract: Aiming at obtaining glucose, we studied the chemical pretreatment (NaOH + H₂SO₄) and the hydrolysis of sugarcane bagasse using as catalyst the acid-treated vermiculite clay. Samples of the bagasse before and after the treatment were characterized as to the fiber content and XRD. It has been found that the chemical pretreatment showed satisfactory results providing a decrease of 40% in the lignin content and of 43% in the hemicellulose content, regarding to the bagasse in natura. Catalytic tests in aqueous solution were performed at 200°C, to evaluate the use of vermiculite treated as a catalyst for the hydrolysis of sugarcane bagasse. The reaction product was filtered and the supernatant was analyzed by high performance liquid chromatography. A yield of 6.18% in glucose was achieved.

Abstract: A preliminary study was performed on enzymatic hydrolysis process for treating empty fruit bunch (EFB) fibre. The bioconversion of cellulose hydrolysis was carried out with soluble cellulase from Trichoderma reesei as the biocatalyst. Crucial trends such as substrate and enzyme loading influencing the enzymatic reaction were also studied in order to enhance the cellulose conversion. The results indicate that as the enzyme loading was increased, the EFB conversion also increased until it reached 115.63 FPU/g of enzyme concentration, beyond this values, the reverse occurred. On the other hand, as the substrate loading was increased the conversion decreased. Inhibition of enzyme adsorption by hydrolysis products appear to be the main cause of the decreasing conversion at increasing enzyme loading and substrate loading.

Abstract: This paper presents the effect of different H₂O: TTIP (Titanium tetraisopropoxide) molar ratios of 8 to 64 during the synthesis using sol-gel associated hydrothermal method on the physical properties. Characterization of all synthesized TiO₂ were accomplished by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) and total surface area measurement, transmission electron microscopy analysis (TEM) and diffuse reflectance UV–Vis spectroscopy (DR-UV-Vis). The XRD analysis showed that anatase (101) was the major phase for all photocatalysts as verified by TEM results. The growth of crystallites with sizes ranging between 10 to 12 nm can be controlled by adjusting the H₂O: TTIP molar ratios. Furthermore, no phase transformation from anatase to rutile observed by increasing the H₂O: TTIP molar ratio. BET data displayed that all prepared photocatalysts are mesoporous materials with type IV adsorption behaviour. DR-UV-Vis spectroscopy revealed that the hydrolysis rate does not give any significant changes on the band gap energies. Among different photocatalysts, the prepared photocatalyst with the H₂O: TTIP molar ratio 32 had the smallest crystal size, particle size, and the highest surface area which are suitable for better photocatalytic performance.

Abstract: This study aimed to analyze the kinetics of enzymatic hydrolysis of cellulose. Cellulase enzyme was obtained from Aspergillus niger grown on filter paper and the hydrolysis process was carried out in solid state. The kinetic reviewed here was the relationship between glucose production and cellulose mass reduction to optimize the parameters of Monod equation at various moisture levels.

Abstract: The aim of this work is the studyof the degradation mechanism of a glass fiber/unsaturated polyester (UP) composite immersed inacidic(H₂SO₄)and alkaline(NaOH)solutionslike establishing a relation between the chemical and the mechanical behaviors of this material. The gravimetric analyses showed a pseudo fickianbehavior for the samples immersed in H₂SO₄ and mass losses with a pseudo-stage of saturation as from 64 hours of immersion for the samples immersed in NaOH.The Fourier transform infrared analysis (FT-IR)of the UP resin revealed the presence of chemical degradation phenomenon (hydrolysis).Microscopic observations (SEM) confirmed the fibres/matrix interfacesdegradation. The effect of these degradations has been reflected one the mechanical properties of the materials.

Abstract: With boron trifluoride methanol complex as raw material, the hydrolysis reaction of boron trifluoride was used to prepare the boric acid. The addition of calcium carbonate is aim to remove the hydrogen fluoride generated in the reaction process, The ultimate objective is making the material being the product of boric acid maximum. Reaction time (T), the ratio of raw materials (molar ratio) and the amount of water were investigated in the influence of the purity and yield of boric acid. The conductivity of mixed solution was determined by conductivity meter, the results determines the end point of the reaction for 20 hours, the optimum solid-liquid ratio is three to one, the amount of water for each mole of boron trifluoride is corresponding 2L distilled water. Product of boric acid yield was 96.26%, the purity was 95.34%.

Abstract: TiO₂ and F-TiO₂ powders were prepared by hydrolysis of titanium tetraisopropoxide with reversed mixing of different hydrolytic reagents. The typeof the hydrolytic agentstronglyinfluences particle size, morphology and phase composition ofpowder.It was found, that the amount of injected water is significantly affects on BET surface area and particle size ofbare TiO₂.The presence offluorinemakes the samplemore porous and preventsanatase to rutile phase transformation under prolonged heat treatment, also particle formed are bigger in comparison with un-doped TiO₂.