Effect Of Acid Pretreatment Research Articles

Effects of Acid Pre-Treatment on Removal of Organic and Inorganic Substances from Black Tilapia Bones and Scales

Fish bones and scales are good sources of gelatin. However, high mineral content in bones and scales often lead to low quality gelatin with high percentage of ash. Therefore, pre-treatment with acid prior to gelatin extraction is necessary. Black tilapia (Oreochromis niloticus) bones and scales were subjected to Hydrochloric (HCl) acid of 0.6 M to 1.4 M for 0 to 32 hr. The suitable pre-treatment conditions were determined using percentage of ash removed and loss of protein from the samples. Results obtained indicate, 99.86 % and 99.84 % of ash can be removed from bones and scales, with 1.4 M HCl (32 hr) and 1.0 M HCl (10 hr), respectively. Further analysis with UV-Vis revealed that, excessive protein breakdown starts to occur at 1.0 M (32 hr) and 0.6 M (12 hr), in bones and scales, respectively. The data suggest using pre-treatment conditions lower than the above to avoid protein loss which may lead to low gelatin yield.

Enhancing phenolic and lipid compound production in oat bran via acid pretreatment and solid-state fermentation with Aspergillus niger

Oat (Avena sativa) processing generates a large amount of by-products, especially oat bran. These by-products are excellent sources of bioactive compounds such as polyphenols and essential fatty acids. Therefore, enhancing the extraction of these bioactive substances and incorporating them into the human diet is critical. This study investigates the effect of acid pretreatment on the solid-state fermentation of oat bran with Aspergillus niger, with an emphasis on the bioaccessibility of phenolic acids and lipid profile. The results showed a considerable increase in reducing sugars following acid pretreatment. On the sixth day, there was a notable increase in the total phenolic content, reaching 58.114 ± 0.09 mg GAE/g DW, and the vanillic acid level significantly rose to 77.419 ± 0.27 μg/g DW. The lipid profile study revealed changes ranging from 4.66 % in the control to 7.33 % on the sixth day of SSF. Aside from biochemical alterations, antioxidant activity measurement using the DPPH technique demonstrated the maximum scavenging activity on day 4 (83.33 %). This study highlights acid pretreatment's role in enhancing bioactive compound accessibility in solid-state fermentation and its importance for functional food development.

Thermal degradation of emerging pollutants in municipal solid wastes and agro wastes: effectiveness of catalysts and pretreatment for the conversion of value added products

In this study, emerging soil pollutants in the form of municipal solid waste (MSW) and agricultural waste were converted into biofuel via thermal degradation process. Among various waste-to-energy conversion processes, the pyrolysis of biomass is considered the most significant due to its maximum biofuel yield than other conversion techniques. Individual and co-pyrolysis of MSW and sugarcane residue (SR) as well as its treated variant (TSR) were performed in a lab-setup fixed-bed reactor with and without catalyst. The effect of acid pretreatment and catalytic effects on the pyrolysis process was assessed in terms of product yields and characterization. The acidic pretreatment of SR and catalyst in the pyrolysis process alters the process yield and its composition. The maximum oil yield of 50.5 wt% was achieved by catalytic co-pyrolysis of MSW + TSR + HZSM5, whereas the maximum gas yield of 38.1 wt% was achieved by catalytic co-pyrolysis of MSW + SR + HZSM5. This suggests that intrinsic minerals present in the biomass and MSW, particularly alkali and alkaline earth metals, have a catalytic effect on the devolatilization of organic material and the char cracking event. The pretreatment of biomass showed considerable improvement in the properties of the produced pyrolysis oil and char. Compared to the pyrolysis oil and char obtained from MSW + SR, the oil and char obtained from MSW + TSR + HZSM5 showed a small increment in their heating values. Pretreatment and the catalytic co-pyrolysis process influenced the structure of the pyrolysis oils, increasing the production of phenolic compounds and aromatic hydrocarbons. The amount of gas components in pyrolysis gas, such as CH4, CO2, and CO also changed more according to the feedstock used for the process. Overall, the HZSM-5 catalyst and co-pyrolysis of MSW with pretreated SR enhanced the pyrolysis conversion of waste municipal solids and agricultural wastes into energy-rich products.

Low temperature non-aqueous dyeing of wool fiber with reactive dyes: A sustainable and eco-friendly method

Conventional wool dyeing usually performed at a boiling point, often destroys the wool structure, consumes plenty energy and water. Aiming at realizing the sustainable cleaning coloration of wool dyeing and keeping the excellent natural quality of wool fiber, a green dyeing technology, non-aqueous dyeing, has been successfully applied. The effect of acid-pretreatment on the reactive dye adsorption behaviors was explored and optimized the dyeing parameters by the design of experiments as well as a single factor screening way. The results demonstrate that acid-pretreatment improved the dye exhaustion rate to 99.79 % effectively by lowering the pH value of wool fiber and increased the dye fixation rate from 75.33 % to 86.93 % by enlarging the dyeing channel. Additionally, the factors that affected wool dyeing were analyzed, approving additional acetic acid had the most significant effect on the wool dyeing. The optimal wool dyeing condition included 1 % on the weight of fiber (o.w.f) acetic acid indicating low-temperature wool dyeing was achieved by this non-aqueous dyeing system at 85 °C for 60min. Furthermore, a higher color depth, constant mechanical properties, good rubbing fastness, and soaping fastness were obtained by this dyeing method. Compared with conventional dyeing, 24.28% energy consumption, 32.50% water usage, and 31.36% wastewater were reduced by this dyeing method. Therefore, sustainable non-aqueous dyeing technology is eco-friendly and has the potential to protect the wool structure from being damaged in the dyeing process.

Alleviating lignin repolymerization facilitated the combined acid and deep eutectic solvent pretreatment of Populus

To elucidate the effects of lignin repolymerization on the combined pretreatment, the sequential acid and deep eutectic solvent (DES) pretreatment was implemented on Populus (poplar) in this study. Effects of acid pretreatment with or without phenolic additives (2-naphthol (2 N) and resorcinol (RS)) on the DES post-treatment efficiency were examined. The results showed that 2 N inhibited the lignin repolymerization in the first-step pretreatment, and slightly enhanced the lignin removal during DES post-treatment. However, RS intensified the lignin repolymerization, significantly decreasing the delignification of DES post-treatment from 73.6%∼79.4% to 39.0∼43.0%. Moreover, the poorer enzymatic hydrolysis was observed in the combined pretreated substrates as compared to the single DES pretreated ones, due to the higher surface lignin coverage. The addition of 2 N counteracted the adverse effects of acid pretreatment on the hydrolysis yields of combined pretreated substrates, and facilitated the yields from 25.8%∼36.0% to 26.2∼67.3%, while the RS addition further decreased the hydrolysis yields to 8.6∼9.6%. The mechanism for the changes on enzymatic digestibilities of the combined pretreated substrates was elucidated.

Effect of pretreatment synergistics on Shenfu low-rank coal pyrolysis in molten metal

The two key factors that significantly impact coal pyrolysis are its structural composition and the medium in which it is carried out. In this study, effects of acid pretreatment (AP), hydrothermal pretreatment (HTP), and acid-hydrothermal synergistic pretreatment (AP-HTP) on Shenfu Low-rank coal (SF) structure were investigated. In molten metals (MM), the distribution and composition of coal pyrolysis products were investigated to evaluate the impact of pretreatment synergistics. The results showed that changing the structure of the coal had a significant effect on the pyrolysis behavior. The molten metal stimulated the pyrolytic conversion of the coal. Pyrolysis in molten metal with AP-HTP synergistic pretreatment coal (SF-AH/MM) increased the tar yield and reduced the water yield. The tar of SF-AH/MM increased aromatic and phenolic compounds, while decreased the aliphatic and oxygen compounds. The H2 increased by 19.48 % and carbon oxides decreased for the gas of SF-AH/MM. Moreover, the char of SF-AH/MM enriched the aromatic structure and the content of the perfect graphite crystal structure, while reduced the degree of graphite lattice defects. The pretreatment synergistics affected the structure of coal and the molten metals enhanced the pyrolysis process, the distribution of products was optimized. Pyrolysis of synergistic pretreatment coal in molten metals is promising to enhance the tar yield, the H2 yield and improved the quality of the char.

Effects of Acid Pretreatment on Purity of Copper Foil Recovered by Electrolytic Refining from Waste Printed Circuit Board

Effects of Acid Pretreatment on Purity of Copper Foil Recovered by Electrolytic Refining from Waste Printed Circuit Board

Effect of Acid Pretreatment of Seeds on the Germination and Early Growth of Albizia lebbek (L) Benth in Makurdi, Benue State-Nigeria

The seeds of A. lebbeck exhibit physical dormancy, which leads to poor seed germination due to a tough seed coat, which has prevented the species from being domesticated in the study area. Pre-sowing treatments are therefore necessary to increase seed germination and reduce germination period. This study aims at the evaluation of the impact of acid pretreatment on seed dormancy and growing seedlings of A. lebbeck for the establishment of plantations in Benue state, Nigeria, where it is lacking. The experiment was laid out in a completely randomized design with six pretreatments (soaked) with the used of acids. The pretreatments include: sulphuric acid (70 % H2SO4) for 2 minutes, 5 minutes, and 10 minutes; nitric acid (70 % HNO3) for 2 minutes, 5 minutes, and 10 minutes; and untreated seeds (control); and replicated thrice. Two seeds were sown in each plastic pot and later thinned to one seed per pot after germination. A total of 144 plastic pots were used. The immersion in 70 % nitric acid for 5 minutes as pretreatment of A. lebbeckyielded the highest germination percentage (50%) and immersion in nitric acid for 2 minutes had the highest emergence index (38). According to the study's findings, pre-treating A. lebbeck with 70 % nitric acid breaks dormancy better and promotes faster growth. Thus, it is recommended that pretreatment of A. lebbeck seeds with 70% nitric acid for five minutes before sowing should be adopted to grow the species faster in the study area.

Effect of acidic pretreatment on the microstructural arrangement and anaerobic digestion of Arachis hypogea shells; and process parameters optimization using response surface methodology

Enzymatic hydrolysis of lignocellulose feedstocks has been observed as the rate-limiting stage during anaerobic digestion. This necessitated the need for pretreatment before anaerobic digestion for an effective and efficient process. Therefore, this study investigated the impact of acidic pretreatment on Arachis hypogea shells, and different conditions of H2SO4 concentration, exposure time, and autoclave temperature were considered. The substrates were digested for 35 days at a mesophilic temperature to assess the impact of pretreatment on the microstructural organization of the substrate. For the purpose of examining the interactive correlations between the input parameters, response surface methodology (RSM) was used. The result reveals that acidic pretreatment has the strength to disrupt the recalcitrance features of Arachis hypogea shells and make them accessible for microorganisms' activities during anaerobic digestion. In this context, H2SO4 with 0.5% v. v−1 for 15 min at an autoclave temperature of 90 °C increases the cumulative biogas and methane released by 13 and 178%, respectively. The model's coefficient of determination (R2) demonstrated that RSM could model the process. Therefore, acidic pretreatment poses a novel means of total energy recovery from lignocellulose feedstock and can be investigated at the industrial scale.

Effect of Acid Pretreatment on the Primary Products of Biomass Fast Pyrolysis

A high load of inorganics in raw lignocellulosic biomass is known to inhibit the yield of bio-oil and alter the chemical reactions during fast pyrolysis of biomass. In this study, palm kernel shell (PKS), an agricultural residue from palm oil production, and two other woody biomass samples (mahogany (MAH) sawdust and iroko (IRO) sawdust) were pretreated with distilled water or an acidic solution (either acetic, formic, hydrochloric (HCl) or sulfuric acid (H2SO4)) before fast pyrolysis in order to investigate its effect on the primary products and pyrolysis reaction pathways. The raw and pretreated PKS, MAH and IRO were pyrolysed at 600 °C and 5 s with a micro-pyrolyser connected to a gas chromatograph–mass spectrometer/flame ionisation detector (GC-MS/FID). Of the leaching solutions, HCl was the most effective in removing inorganics from the biomass and enhancing the primary pyrolysis product formed compared to the organic acids (acetic and formic acid). The production of levoglucosan was greatly improved for all pretreated biomasses when compared to the original biomass but especially after HCl pretreatment. Additionally, the relative content of the saccharides was maximised after pretreatment with H2SO4, which was due to the increased production of levoglucosenone. The relative content of the saccharides increased by over 70%. This increase may have occurred due to a possible reaction catalysed by the remaining acid in the biomass. The production of furans, especially furfural, was increased for all pretreatments but most noticeable when H2SO4 was used. However, the relative content of acids and ketones was generally reduced for PKS, MAH and IRO across all leaching solutions. The relative content of the phenol-type compound decreased to a large extent during pyrolysis after acid pretreatment, which may be attributed to dehydration and demethoxylation reactions. This study shows that the production of valuable chemicals could be promoted by pretreatment with different acid solutions.

Valorization of Groundnut Shell Biomass for Biosorption of Hexavalent Chromium from Aqueous Solution

Biosorption is a cost-effective biotechnological innovation for the removal of heavy metals from aqueous solutions. There is widespread research into ways of utilizing agricultural residues to achieve zero waste. Groundnut shells are biodegradable waste available in large quantities. This study investigated the use of groundnut shells for the biosorption of chromium (VI) ions from an aqueous solution. Groundnut shells were cleaned and crushed to make fractions of particle size in the range of 90-1000 µm. The point of zero charge (pHPZC) and the distribution of oxygenated acidic and basic surface functional groups were determined. In batch experiments, the effect of acid pre-treatment, initial metal concentration, biosorbent particle size, biosorbent dosage, and contact time on biosorption was investigated. The biomass was found to have a pHPZC value of 6 and was dominated by acidic groups. The best biosorption activity was observed at 20 mg/L initial metal concentration and a biosorbent dosage of 10%. The effect of contact time was dependent on the initial chromium (VI) concentration. At 20 mg/L initial chromium (VI) concentration, the biosorption process reached equilibrium within 60 minutes whilst at high (>80 mg) chromium (VI) concentration equilibrium was not reached, even after 240 minutes. The best biosorption activity was observed with acid-treated biomass of particle size 300 µm. The adsorption fitted best with the Langmuir isotherm model and the pseudo-second-order kinetic model (R2 > 0.9982). Groundnut shell biomass has the potential for the removal of chromium (VI) ions from aqueous solutions and possibly from chromium-polluted effluents on an industrial scale.

Effect of Acid Pretreatment on PhysicoChemical, Optical, Functional, Thermal, and Morphological Characteristics of Unripe Plantain and Banana Flour

Effect of Acid Pretreatment on PhysicoChemical, Optical, Functional, Thermal, and Morphological Characteristics of Unripe Plantain and Banana Flour

Developing pretreatment methods to promote the production of biopolymer and bioethanol from residual algal biomass (RAB)

This study investigates the effect of acidic pretreatment (HT-ACPT), enzymatic pretreatment (ENZ-PT), and microwave laser-hydrogen peroxide-Fe-nanoparticle pretreatment (Mv-H2O2-Fe-PT) on the production of bioethanol (bio-eth.) and biopolymer (bio-p) from residual algal biomass (RAB). The effectiveness of these pretreatments is based on using the entire RAB and maximizing sugar liberation to produces bio-p and bio-eth under optimized conditions. The Mv-H2O2-Fe-PT yielded the maximum total and soluble sugar liberation of 0.988 ± 0.08 and 0.6888 ± 0.08 g/gDCW compared with HT-ACPT (0.588 ± 0.02 and 0.488 ± 0.02 g/gDCW) and ENZ-PT (0.528 ± 0.06 and 0.428 ± 0.06 g/gDCW). All pretreatment methods split the β-1, 4-glycosidic bonds into cellulose and liberate sugars that were later used to produce bio-p and bio-eth. The algal strains treated by Mv-H2O2-Fe-PT produced the highest bio-p of 0.740 ± 0.004 gpolyemer/gDCW, which is 1.3 folds higher than the productivity of HT-ACPT and ENZ-PT. The HT-ACPT and ENZ-PT produced 67 to 72 % and 59 to 63 % lower biopolymer yield. The maximum bioethanol production (Mbio−ethP) of 0.950 ± 0.005 mL/gRAB was achieved using microalgae pretreated with Mv-H2O2-Fe-PT and incubated at pH = 5.5 and 37 °C. The Mbio−ethP was negatively affect by increasing the pH or decreasing the temperature. The Mbio−ethP decreased to 0.853 ± 0.002 mL/gRAB by increasing the pH to 6 and to 0.761 ± 0.002 mL/g when the temperature decreased to 33 °C. The Mbio−ethP as a fraction of theoretical yield (%ThY) were in the ranges of 21 to 33 %, 33.3 to 51.1 % and 59.52 to 91.2 % for RAB pretreated with HT-ACPT, ENZ-PT and Mv-H2O2-Fe-PT, respectively. The produced bio-p exhibited excellent properties and can be used in a variety of applications including soil additives, biofuel production, regenerative medicine, and other medical applications. The Mv-H2O2-Fe-PT pretreatment offers complete use of RAB to produce different bio-products.

Effect of Acid Pretreatment on the Anaerobic Codigestion of Sewage Sludge, Chicken Litter, and Sugarcane Waste (SCW) for Biogas Production

Effect of Acid Pretreatment on the Anaerobic Codigestion of Sewage Sludge, Chicken Litter, and Sugarcane Waste (SCW) for Biogas Production

Effect of acid pre-treatment and potting media on seed germination and early seedling growth of Albizia Lebbek

Effect of acid pre-treatment and potting media on seed germination and early seedling growth of Albizia Lebbek

Towards green whiskey production: Anaerobic digestion of distillery by-products and the effects of pretreatment

Using renewable biogas from the anaerobic digestion of distillery by-products as a low-carbon heat source can decarbonize the distillery process and support the distillery industry to transition to a more sustainable production process. This study investigated the anaerobic digestion performance of different types of whiskey by-products and the effects of acid pretreatment on the digestion of solid by-products. Results of biomethane potential assays showed that the methane yield from the unprocessed by-products was 330 mL/g volatile solids (VS) from draff, 495 mL/g VS from thin stillage, and 503 mL/g VS from thick stillage. For the processed by-products the specific methane yield was 370 mL/g VS from cake maize, 382 mL/g VS from wet distillers’ grains with solubles (WDGS), and 545 mL/g VS from syrup. Acid pretreatment (1% H2SO4 at 135 °C for 15 min) did not significantly improve the methane yield from solid by-products (such as draff and WDGS) but reduced the digestion time by 54.5% for cake maize. The microbial community analysis revealed that methane production from the untreated and acid-pretreated solid by-products (draff and WDGS) was mainly through the hydrogenotrophic methanogenesis pathway. The gross thermal energy in the form of methane produced from 100 tonnes of mixed unprocessed by-products (draff, thin stillage, and thick stillage) was calculated as 24.4 MWthh equivalent to 60.6% of the thermal energy consumed in whiskey production, which effected the same percentage of CO2 emissions reduction.

Formaldehyde oxidation on Pd/USY catalysts at room temperature: The effect of acid pretreatment on supports

The complete catalytic oxidation of formaldehyde (HCHO) to CO2 and H2O at room temperature is a green route for indoor HCHO removal. Zeolite is an excellent carrier material for HCHO oxidation due to its large surface area, intricate pores and high adsorption capacity. However, the zeolite-supported noble metal catalysts have currently shown relatively low activity especially at room temperature. In this work, we present a facile acid treatment strategy for zeolite catalysts to improve the hydroxyl concentration and further enhance their catalytic activity for HCHO oxidation. Activity tests illustrated that HCHO could be completely oxidized to CO2 and H2O at a nearly 100% conversion rate with a weight hourly space velocity (WHSV) of 150,000 mL/(g∙hr) at 25°C, when the support of Pd/USY catalysts was pretreated by hydrochloric acid with a concentration of 0.20 mol/L. The characterization results revealed that the active hydroxyl groups originated from the dealumination in the acid treatment play a key role in the HCHO oxidation reaction. The deduced reaction mechanism suggests that bridging hydroxyl groups may oxidize HCHO to dioxymethylene (DOM) species and terminal hydroxyl groups are responsible for the transformation of DOM groups to formate (HCOO) species.

Effect of Acid Pretreatment on the Primary Products of Biomass Fast Pyrolysis

Effect of Acid Pretreatment on the Primary Products of Biomass Fast Pyrolysis

Influence of extraction times on physical and functional properties of gelatin from salted jellyfish by-products

By-products of the marine industry have gained attention for producing valuable food ingredients like gelatin, which might benefit food applications and decrease food waste. Gelatin is the only protein-based food hydrocolloid, mainly used for gelling, viscosity, or emulsifying in the food industry. So far, a number of researchers have reported that by-products of salted jellyfish can produce jellyfish gelatin. The quality of jellyfish gelatin gel depends on several factors including hydrochloric acid pretreatment, extraction temperature, and extraction time. However, the functional properties such as foaming and emulsifying of jellyfish gelatin are not well understood. This research was aimed at investigating the hydrochloric acid pretreatment effect of extraction times (12, 24, and 48 h) at 60 °C on the resulting gelatin's yield, physical, and functional properties. Results showed that jellyfish gelatin's yield, gel strength, and viscosity significantly increased with increasing extraction times. Jellyfish gelatin yields were 2.74-14.07%. The gel strength of jellyfish gelatin extracted for 48 h (325.97±2.84 g) was higher than that of jellyfish gelatins extracted for 12 h (210.46±3.97 g) and 24 h (261.60±3.25 g). All jellyfish gelatins can form gels at 4 °C. Viscosity values of jellyfish gelatin were 23.00-24.50 centipoise. The foaming capacity and foaming stability of jellyfish gelatin were 12.28-17.54% and 10.52-15.78%, respectively. The emulsification activity index of jellyfish gelatin was 13.11-13.30 m2/g, and the emulsification stability index was 39.19-56.42%. As a result, varied gelatin extraction periods influenced jellyfish gelatin's physical and functional properties, indicating that the extended extraction time of 48 h delivered the jellyfish gelatin that can be used as a foaming and emulsifying agent. Therefore, turning the jellyfish by-products into food ingredients like gelatin would increase product values and potential uses in the food and medical applications.

Efficacy of dental materials in terms of apparent mineral density restoration: Composite resin, glass ionomer cement and infiltrant

In the present study the methodology for assessing the effect of dental treatments on the mineral density of pathological tooth tissues using micro-CT was proposed. The mineral density values of early carious enamel and dentine in its vicinity with the apparent mineral density of the same tissues modified by two filling materials and an infiltrant were compared. Five cases were considered ex vivo. The high efficacy of laboratory micro-CT for carrying out such observations has been demonstrated. The composite resin was found to be very close in terms of the apparent mineral density to natural enamel as opposed to glass ionomer cement. Also, unlike the latter, the composite resin showed a small amount of internal structural artifacts. When studying the effect of the infiltrant on the apparent mineral density of carious enamel and dentine bordering it, a significant negative effect of acid pre-treatment was observed. In none of the infiltration cases considered was the apparent mineral density of the modified enamel restored to its natural values. In one case the infiltrant reached the dentine and increased its apparent mineral density.