Dilute H2SO4 Research Articles

Biogas Production from Distilled Grain Waste by Thermophilic Dry Anaerobic Digestion: Pretreatment of Feedstock and Dynamics of Microbial Community

Distilled grain waste (DGW) eluted from the Chinese liquor making process poses potential serious environmental problems. The objective of this study is to evaluate the feasibility of converting DGW to biogas by thermophilic dry anaerobic digestion. To improve biogas production, the effects of dilute H2SO4 and thermal pretreatment on DGW were evaluated by biochemical methane potential (BMP) tests. The results indicate that 90°C thermal pretreatment provided the highest methane production at 212.7mL/g-VTSadd. The long-term thermophilic dry anaerobic digestion process was conducted in a 5-L separable flask for more than 3years at a volatile total solid (VTS) loading rate of 1g/kg-sludge/d, using synthetic waste, untreated and 90°C thermal pretreated DGW as the feedstock, respectively. A higher methane production, 451.6mL/g-VTSadd, was obtained when synthetic waste was used; the methane production decreased to 139.4mL/g-VTSadd when the untreated DGW was used. The 90°C thermal pretreated DGW increased the methane production to 190.5mL/g-VTSadd, showing an increase of 36.7% in methane production compared with that using untreated DGW. The microbial community structure analysis indicates that the microbial community in the thermophilic dry anaerobic digestion system maintained a similar structure when untreated or pretreated DGW was used, whereas the structure differed significantly when synthetic waste was used as the feedstock.

Solvent extraction of calcium and magnesium from concentrate nickel sulfate solutions using D2HEPA and Cyanex 272 extractants

Selective solvent extraction of Ca and Mg was applied to purify Ni from a concentrate sulfate solution ([Ni]=88g/L, [Mg]=3.1g/L, [Ca]=0.5g/L). In the first extraction circuit using D2EHPA as an extractant, 98.6% Ca were extracted (2 stages, [D2EHPA]=0.3M, pH3, 50°C, A/O ratio=1). The co-extracted Ni (~2.8%) was selectively stripped out (99%) from the loaded organic phase with only 2.6% Ca using a dilute H2SO4 solution (2 stages, [H2SO4]=0.038M, 50°C, A/O ratio=1). Over 99% Ca were stripped out from the loaded D2EHPA in one theoretical stage with 2M HCl (O/A ratio=15). The aqueous solution depleted in Ca was subjected to the second extraction circuit using Cyanex 272 as an extractant, where 99% Mg were extracted (3 stages, [Cyanex 272]=0.32M, pH5.7, 50°C, A/O ratio=1). The co-extracted Ni (~6.9%) was recovered (99%) from the loaded organic phase with only 2.1% Mg using a dilute H2SO4 solution (3 stages, [H2SO4]=0.031M, 50°C, A/O ratio=1). Magnesium was stripped out (>99%, 50°C) from the loaded Cyanex 272 in one theoretical stage using 2M H2SO4 or 3M HCl (O/A ratio=20 or 11, respectively). The purified liquor with approximately 80g/L Ni is suitable for electrowinning. The apparent equilibrium constants using real concentrations of metals were obtained.

Systematic Approach to the Development of Microfabricated Biosensors: Relationship between Gold Surface Pretreatment and Thiolated Molecule Binding.

Despite the increasing popularity of microfabricated biosensors due to advances in technologic and surface functionalization strategies, their successful implementation is partially inhibited by the lack of consistency in their analytical characteristics. One of the main causes for the discrepancies is the absence of a systematic and comprehensive approach to surface functionalization. In this article microfabricated gold electrodes aimed at biosensor development have been systematically characterized in terms of surface pretreatment, thiolated molecule binding, and reproducibility by means of X-ray photoelectron scattering (XPS) and cyclic voltammetry (CV). It has been shown that after SU-8 photolithography gold surfaces were markedly contaminated, which decreased the effective surface area and surface coverage of a model molecule mercaptohexanol (MCH). Three surface pretreatment methods compatible with microfabricated devices were compared. The investigated methods were (i) cyclic voltammetry in dilute H2SO4, (ii) gentle basic piranha followed by linear sweep voltammetry in dilute KOH, and (iii) oxygen plasma treatment followed by incubation in ethanol. It was shown that all three methods significantly decreased the contamination and increased MCH surface coverage. Most importantly, it was also revealed that surface pretreatments may induce structural changes to the gold surfaces. Accordingly, these alterations influence the characteristics of MCH functionalization.

Comparison of Dilute Acid, Alkali, and Biological Pretreatments for Reducing Sugar Production from Eucalyptus

The effects of chemical pretreatments (dilute H2SO4, dilute NaOH, and NH4OH) and biological pretreatments (Coriolus versicolor and Daedalea quercina) on the enzymatic hydrolysis of Eucalyptus were investigated. The results showed that Eucalyptus obtained from different regions possess similar chemical compositions and that the optimum particle sizes for reducing sugar production were 60- to 80-mesh. Contrary to the negative influences of a dilute H2SO4 pretreatment, an alkali pretreatment showed positive effects on Eucalyptus saccharification. This phenomenon may had been attributed to the efficient removal of lignin and the stronger structural damage during the alkali pretreatment process. In comparison with the chemical pretreatments, a higher reducing sugar yield could be achieved from the biological pretreated Eucalyptus. The highest reducing sugar yield of 97.14 mg/g was obtained from the Guangxi (GX) Eucalyptus that was pretreated with Daedalea quercina.

Formation and evolution of nanoporous bimetallic Ag-Cu alloy by electrochemically dealloying Mg-(Ag-Cu)-Y metallic glass

A three-dimensional nanoporous bimetallic Ag-Cu alloy with uniform chemical composition has been fabricated by dealloying Mg65Ag12.5Cu12.5Y10 metallic glass in dilute (0.04M) H2SO4 aqueous solution under free-corrosion conditions. The nanoporous Ag-Cu evolves through two distinct stages. First, ligaments of the nanoporous structure, consisting of supersaturated Ag(Cu) solid solution with a constant Ag/Cu mole ratio of 1:1, are yielded. Second, with excessive immersion, some Cu atoms separate from the metastable nanoporous matrix and form spherical Cu particles on the sample surface. Formation and evolution mechanisms of the nanoporous structure are proposed.

Bio-ethanol production from wet coffee processing waste in Ethiopia.

Large amounts of coffee residues are generated from coffee processing plants in Ethiopia. These residues are toxic and possess serious environmental problems following the direct discharge into the nearby water bodies which cause serious environmental and health problems. This study was aimed to quantify wet coffee processing waste and estimate its bio-ethanol production. The study showed that the wastes are potential environmental problems and cause water pollution due to high organic component and acidic nature. The waste was hydrolyzed by dilute H2SO4 (0.2, 0.4, 0.6, 0.8 and 1 M) and distilled water. Total sugar content of the sample was determined titrimetrically and refractometry. Maximum value (90%) was obtained from hydrolysis by 0.4 M H2SO4. Ethanol production was monitored by gas chromatography. The optimum yield of ethanol (78%) was obtained from the sample hydrolyzed by 0.4 M H2SO4 for 1 h at hydrolysis temperature of 100 °C and after fermentation for 24 h and initial pH of 4.5. Based on the data, it was concluded that reuse of the main coffee industry wastes is of significant importance from environmental and economical view points. In conclusion, this study has proposed to utilize the wet coffee processing waste to produce bio-ethanol which provides the alternative energy source from waste biomass and solves the environmental waste disposal as well as human health problem.

Onsite-detection of barium and nickel from river, pond and tap water samples using gold nanoparticles as a chemical sensor

We report a simple, selective and sensitive colorimetric assay for onsite determination of Ni(II) and Ba(II) from river, pond and tap water samples using the localized surface plasmon resonance (LSPR) of malonate capped gold nanoparticles (AuNPs) as a chemical sensor. The method is based on the color change and red shift of LSPR absorption band in visible region that caused by the aggregation of NPs because of the coordination complex between Ba(II) and Ni(II) with carboxylate ions of malonate capped AuNPs. The determination of Ba(II) and NI(II) in a same sample was performed by masking one of the analyte at a time, EDTA was used to mask Ni(II) for detection of Ba(II) and dilute H2SO4 was used to mask the Ba(II) for detection of Ni(II). The linear range for quantitative determination of Ba(II) and NI(II) were found in the range of 15–500 and 10–500ngmL−1 with a limit of detection of 5 and 3ngmL−1, respectively. The advantages of the AuNPs based chemical sensor is found to be simple, rapid and sensitive as well as it can be applied at the sample source for trace detection of Ba(II) and Ni(II) in various environmental samples.

Attempts to produce blast furnace coke from Victorian brown coal. 4. Low surface area char from alkali treated brown coal

A Victorian brown coal (VBC) has been heated with strong aqueous KOH under severe conditions, neutralized with dilute H2SO4 and then hot-briquetted with or without coking coal tar pitch as a binder, optionally air cured and finally carbonized. The final products were evaluated as a blast furnace (BF) coke substitute. The least reactive final product had a much lower reactivity than the product obtained by carbonizing a hot-briquetted VBC-VBC tar mixture. Furthermore, the final product obtained from alkali treated coal had a surface area as low as that of a BF coke. However, the reactivity remained higher and the amount of graphitic structure lower than those of a BF coke. In addition, although the coal/coal-binder mixture, like coking coal, appeared to have fused during carbonization, the final products had virtually no meso+macropore volume, in contrast to a typical BF coke.

Removal of iron from sythetic copper leach solution using a hydroxy-oxime chelating resin

Iron removal is a common procedure in hydrometallurgy of non-ferrous metallic ores. Chemical precipitation and solvent extraction are currently the main methods employed for separation of iron from copper leach solution. However, chemical precipitation methods have the problem of producing large amounts of iron precipitates, and/or requiring high temperature and high pressure conditions for precipitation. The precipitates are difficult to separate from the solution. Emulsification is a general problem for solvent extraction, which causes loss of extractants and contamination of the electrolyte. A common problem for solvent extraction and chelating ion exchange processes is the difficult iron stripping process. Therefore, finding an efficient and environmentally friendly method for iron removal is of great significance. In this paper, new processes of using ion exchange resins to remove iron from copper leach solution have been investigated.Salicylic acid, amino carboxylic acid, amino phosphonic acid and hydroxy-oxime resins were employed to adsorb iron from a synthetic copper leach solution containing 40g/L of Cu2+ and 36g/L of Fe3+. It was found that a hydroxy-oxime resin, named Z-Fe, has excellent adsorption selectivity on Fe3+. Desorption behavior of the resin was studied by two step elutions using dilute H2SO4 and oxalic acid solution, respectively. After optimizing the adsorption-elution processes, the extent of removal of iron from the simulated copper leach solution using resin Z-Fe was 89.83%, while copper recovery could reach 100% in closed circuit processing.

Development of an Eco-Friendly Method for Iron Extraction and Determination in Pharmaceuticals Using Ciprofloxacin Drug as Chelating agent

A method is developed for the determination of iron (III) in pharmaceutical preparations by coupling cloud point extraction (CPE) and UV-Vis spectrophotometry. The method is based on the reaction of Fe(III) with excess drug ciprofloxacin (CIPRO) in dilute H2SO4, forming a hydrophobic Fe(III)- CIPRO complex which can be extracted into a non-ionic surfactant Triton X-114, and iron ions are determined spectrophotometrically at absorption maximum of 437 nm. Several variables which impact on the extraction and determination of Fe (III) are optimized in order to maximize the extraction efficiency and improve the sensitivity of the method. The interferences study is also considered to check the accuracy of the procedure. The results have shown that the preconcentration factor of 71 fold leading to obtain a limit of detection of 2.67 ng mL-1 with linear calibration range of 5-150 ng mL-1 (r=0.9998) and a superb sensitivity in terms of molar absorptivity of 1.13x106 L.mol-1.cm-1 . The mean percent recovery of 99.78±0.53% and the precision (RSD %) ranged from 1.96 to 0.76 are achieved. The developed method is applied to the determination of iron in four selected pharmaceutical drugs. The experimental values agree statistically with the quoted values stated by the manufacturer’ companies.

Pilot‐scale cellulosic ethanol production using eucalyptus biomass pre‐treated by dilute acid and steam explosion

AbstractThe widespread deployment of commercial‐scale cellulosic ethanol currently hinges on developing and evaluating scalable processes whilst broadening feedstock options. This study investigates whole Eucalyptus grandis trees as a potential feedstock and demonstrates dilute acid pre‐treatment (with steam explosion) followed by pre‐saccharification simultaneous saccharification fermentation process (PSSF) as a suitable, scalable strategy for the production of bioethanol. Biomass was pre‐treated in dilute H2SO4 at laboratory scale (0.1 kg) and pilot scale (10 kg) to evaluate the effect of combined severity factor (CSF) on pre‐treatment effectiveness. Subsequently, pilot‐scale pre‐treated residues (15 wt.%) were converted to ethanol in a PSSF process at 2 L and 300 L scales. Good polynomial correlations (n = 2) of CSF with hemicellulose removal and glucan digestibility with a minimum R2 of 0.91 were recorded. The laboratory‐scale 72 h glucan digestibility and glucose yield was 68.0% and 51.3%, respectively, from biomass pre‐treated at 190 °C /15 min/ 4.8 wt.% H2SO4. Pilot‐scale pre‐treatment (180 °C/ 15 min/2.4 wt.% H2SO4 followed by steam explosion) delivered higher glucan digestibility (71.8%) and glucose yield (63.6%). However, the ethanol yields using PSSF were calculated at 82.5 and 113 kg/ton of dry biomass for the pilot and the laboratory scales, respectively. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd

Regeneration of commercial selective catalyst reduction catalysts deactivated by Pb and other inorganic elements

The regeneration of commercial SCR (Selective Catalyst Reduction) catalysts deactivated by Pb and other elements was studied. The deactivated catalyst samples were prepared by chemical impregnation with mixed solution containing K2SO4, Na2SO4, CaSO4, Pb(NO3)2 and NH4H2PO4. A novel method combining Ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) and H2SO4 solution (viz. catalysts treated by dilute EDTA-2Na and H2SO4 solution in sequence) was used to recover the activity of deactivated samples, and the effect was compared with single H2SO4, oxalic acid, acetic acid, EDTA or HNO3 solutions. The surface structure, acidity and reducibility of samples were characterized by N2 adsorption–desorption, inductively coupled plasma optical emission spectrometer (ICP-OES), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), H2-temperature programmed section (H2-TPR), NH3-temperature programmed desorption (NH3-TPD) and in situ DRIFTS. Impurities caused a decrease of specific surface area and surface reducibility, as well as Brønsted acid sites, and therefore led to severe deactivation of the SCR catalyst. The use of an acid solution alone possibly eliminated the impurities on the deactivated catalyst to some extent, and also increased the specific surface area and Brønsted acid sites and promoted the surface reducibility, thus recovered the activity partially. The combination of EDTA-2Na and H2SO4 could remove most of the impurities and improve the activity significantly. The removal of Pb should be an important factor for regeneration. Due to a high removal rate for Pb and other impurities, the combination of EDTA-2Na and H2SO4 solutions provided the best efficiency.

Novel integrated mechanical biological chemical treatment (MBCT) systems for the production of levulinic acid from fraction of municipal solid waste: A comprehensive techno-economic analysis

This paper, for the first time, reports integrated conceptual MBCT/biorefinery systems for unlocking the value of organics in municipal solid waste (MSW) through the production of levulinic acid (LA by 5wt%) that increases the economic margin by 110–150%. After mechanical separation recovering recyclables, metals (iron, aluminium, copper) and refuse derived fuel (RDF), lignocelluloses from remaining MSW are extracted by supercritical-water for chemical valorisation, comprising hydrolysis in 2wt% dilute H2SO4 catalyst producing LA, furfural, formic acid (FA), via C5/C6 sugar extraction, in plug flow (210–230°C, 25bar, 12s) and continuous stirred tank (195–215°C, 14bar, 20min) reactors; char separation and LA extraction/purification by methyl isobutyl ketone solvent; acid/solvent and by-product recovery. The by-product and pulping effluents are anaerobically digested into biogas and fertiliser. Produced biogas (6.4MWh/t), RDF (5.4MWh/t), char (4.5MWh/t) are combusted, heat recovered into steam generation in boiler (efficiency: 80%); on-site heat/steam demand is met; balance of steam is expanded into electricity in steam turbines (efficiency: 35%).

Repulsive interactions induced by specific adsorption: Anomalous step diffusivity and inadequacy of nearest-neighbor Ising model: (part I experimental)

This is Part I of two closely related papers, where we show that the specific adsorption of anions leads to a failure of the nearest-neighbor Ising model to describe island perimeter curvatures on Au(100) electrodes in dilute KBr, HCl and H2SO4 electrolytes and the therewith derived step diffusivity vs. step orientation. This result has major consequences for theoretical studies aiming at the understanding of growth, diffusion and degradation phenomena. Part I focuses on the experimental data.As shown theoretically in detail in Part II (doi:10.1016/j.susc.2016.03.022), a set of nearest-neighbor and next-nearest-neighbor interaction energies (ϵNN, ϵNNN) can uniquely be derived from the diffusivity of steps along 〈100〉 and 〈110〉. We find strong repulsive next-nearest neighbor (NNN) interaction in KBr and HCl, whereas NNN interaction is negligibly for H2SO4. The NNN repulsive interaction energy ϵNNN therefore correlates positively with the Gibbs adsorption energy of the anions. We find furthermore that ϵNNN increases with increasing Br− and Cl− coverage.The results for ϵNNand ϵNNN are quantitatively consistent with the coverage dependence of the step line tension. We thereby establish a sound experimental base for theoretical studies on the energetics of steps in the presence of specific adsorption.

Utilization of palm kernel cake as a renewable feedstock for fermentative hydrogen production

Fermentative hydrogen generation was studied using palm kernel cake (PKC) as sustainable cellulosic biomass. PKC was subjected to an acid hydrolysis approach using dilute H2SO4 (7% v/v). PKC hydrolysate obtained was then diluted (70%) and used as a substrate for hydrogen generation. Chemical analysis showed that the main fermentable sugars in diluted PKC hydrolysate were glucose, xylose and mannose with the concentrations of 2.75 g/L, 2.60 g/L and 27.75 g/L, respectively. Hydrogen production was carried out by the cultivation of Clostridium acetobutylicum YM1 on PKC hydrolysate. The effect of incubation temperature, the initial pH of culture medium and microbial inoculum size on hydrogen production was studied using a statistical model. The analysis of the model generated showed that the initial pH value of the culture medium and inoculum size had significant effects on the hydrogen production. The study showed that the optimum conditions for the biohydrogen production were 30.57 °C temperature, pH 5.5 and 20% inoculum size. A verification experiment was performed in the optimum conditions determined. Experimental results of the verification test showed that a cumulative hydrogen volume of 1575 ml/L was generated with consuming 2.75 g/L glucose, 2.20 g/L xylose and 16.31 g/L mannose.

Removal of Strontium Ions by Synthetic Nano Sodalite Zeolite from Aqueous Solution

In this research, the zeolite sodalite, as an inorganic ion exchange material, was chemically produced in the template-free synthesis and evaluated in order to facilitate the sorption of strontium ions from aqueous solutions in batch operations onto acid treated zeolite with dilute H2SO4 solutions. The following indicates what the batch experiments included: a sorbent amount of 0.25 g in 100 mL of strontium solution (50 mg/L), a contact time of 80 min, pH 6 and a 20 oC temperature. To study the kinetics of removal process, three equations, i.e. Morris–Weber, Lagergren (pseudo first order) and pseudo second order were used. The sorption data were applied to the Langmuir, Freundlich, Dubnin-Randkovich (D-R) and Temkin models in order to estimate the sorption capacity, intensity and energy. An evaluation of the thermodynamic parameters ΔH, ΔS and ΔG was done. It was found out from thermodynamic parameters that the sorption of strontium onto zeolite was feasible, spontaneous and endothermic under studied conditions.

Pretreatment of Dried Distiller Grains with Solubles by Soaking in Aqueous Ammonia and Subsequent Enzymatic/Dilute Acid Hydrolysis to Produce Fermentable Sugars.

Dried distillers grains with solubles (DDGS), a co-product of corn ethanol production in the dry-grind process, was pretreated by soaking in aqueous ammonia (SAA) using a 15% w/w NH4OH solution at a solid/liquid ratio of 1:10. The effect of pretreatment on subsequent enzymatic hydrolysis was studied at two temperatures (40 and 60°C) and four reaction times (6, 12, 24, and 48h). Highest glucose yield of 91% theoretical was obtained for the DDGS pretreated at 60°C and 24h. The solubilized hemicellulose in the liquid fraction was further hydrolyzed with dilute H2SO4 to generate fermentable monomeric sugars. The conditions of acid hydrolysis included 1 and 4wt% acid, 60 and 120°C, and 0.5 and 1h. Highest yields of xylose and arabinose were obtained at 4wt% acid, 120°C, and 1h. The fermentability of the hydrolysate obtained by enzymatic hydrolysis of the SAA-pretreated DDGS was demonstrated in ethanol fermentation by Saccharomyces cerevisiae. The fermentability of the hydrolysate obtained by consecutive enzymatic and dilute acid hydrolysis was demonstrated using a succinic acid-producing microorganism, strain Escherichia coli AFP184. Under the fermentation conditions, complete utilization of glucose and arabinose was observed, whereas only 47% of xylose was used. The succinic acid yield was 0.60g/g total sugar consumed.

Development of a novel method for the removal of diazinon pesticide from aqueous solution and modeling by artificial neural networks (ANN)

In this study, perlite was used as a low-cost source of Si and Al to synthesize the sodalite zeolite via hydrothermal synthesis method. Cu2O nanoparticles (30–60nm) were coated on a bed of sodalite zeolite. Toward this aim, a series of batch adsorption experiments was carried out and the sorption of diazinon from aqueous solutions on acid treated zeolite (ATZ) with dilute H2SO4 solutions and modified zeolite by Cu2O nanoparticles (MZ) were also determined. Results showed that Cu2O nanoparticles have a significant effect on the diazinon removal processing from aqueous solution. Maximum adsorption rates were 98.2% (with 0.2, 20, 6 of adsorbent dose, contact time and pH, respectively, for MZ) and 63.4% (with 0.3, 80, 6 of adsorbent dose, contact time and pH, respectively, for ATZ). Three equations, i.e., Morris–Weber, Lagergren (pseudo first order) and pseudo second order have been applied to study the kinetics of removal process. The diazinon sorption process was well described by the pseudo second order (type 2) kinetic model. The Langmuir, Freundlich, Temkin and Dubnin–Randkovich (D–R) models were tested on sorption data to estimate the sorption capacity, intensity and energy. Langmuir (type 1) isotherm provided the best fit to the equilibrium data with maximum adsorption capacity of 61.73 and 15.10mg/g for MZ and ATZ, respectively. The thermodynamic parameters ΔH, ΔS and ΔG were evaluated. Thermodynamic parameters showed that the sorption of diazinon onto zeolite was feasible, spontaneous and exothermic under studied conditions. Artificial neural network (ANN) model was also applied for modeling of diazinon removal from aqueous solution by ATZ and MZ. There was a good agreement between the experimental and predicted values with seven neurons in hidden layer.

Production of hydrogen, ethanol and volatile fatty acids through co-fermentation of macro- and micro-algae

Algae may be fermented to produce hydrogen. However micro-algae (such as Arthrospira platensis) are rich in proteins and have a low carbon/nitrogen (C/N) ratio, which is not ideal for hydrogen fermentation. Co-fermentation with macro-algae (such as Laminaria digitata), which are rich in carbohydrates with a high (C/N) ratio, improves the performance of hydrogen production. Algal biomass, pre-treated with 2.5% dilute H2SO4 at 135°C for 15min, effected a total yield of carbohydrate monomers (CMs) of 0.268g/g volatile solids (VS). The CMs were dominating by glucose and mannitol and most (ca. 95%) were consumed by anaerobic fermentative micro-organisms during subsequent fermentation. An optimal specific hydrogen yield (SHY) of 85.0mL/g VS was obtained at an algal C/N ratio of 26.2 and an algal concentration of 20g VS/L. The overall energy conversion efficiency increased from 31.3% to 54.5% with decreasing algal concentration from 40 to 5 VS g/L.

Hemicellulose isolation, characterization, and the production of xylo-oligosaccharides from the wastewater of a viscose fiber mill

Viscose fiber mills generate a lot of wastewater enriched with hemicelluloses. The structure of the hemicellulose in the wastewater was characterized and the hemicellulose was isolated to produce xylo-oligosaccharides (XOS). It was confirmed that the hemicellulose was mainly 4-O-methylglucuronoxylan with a small amount of glucomannan and xyloglucan. The 4-O-methylglucuronoxylan was completely de-acetylated and linear with a few 4-O-methyl glucuronic acid attached. After purified by the acid precipitation and washing, the hemicellulose was pretreated by dilute acid, and then subjected to xylanase hydrolysis. After the dilute H2SO4 pretreatment at pH 2.6 and 150°C for 30min and the followed xylanase hydrolysis (65IU/g xylan), the total XOS yield was improved from 0.215 to 0.578g/g xylan. The percentage of XOS in the final sugar product was 68.9%. These results demonstrated the potential economical and environmental benefits of the process to utilize the byproducts from viscose fiber mills.