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Cashew apple, by-product of cashew nut processing industry, is rich in vitamins, polyphenols, sugars, minerals, amino acids and dietary fibres. Despite being highly nutritious, it is an underutilized fruit due to its high perishability and astringent taste. In this study, a shelf-life extension of cashew apples using chemical pre-treatment has been investigated. The effect of chemical pre-treatment using a solution containing calcium chloride, sodium chloride, and potassium meta-bisulphite was investigated and its effect on physicochemical parameters such as pH, total soluble solids, physiological weight loss, colour, texture, total phenolic content, antioxidant, vitamin C, and enzyme inhibition (%) were studied. The chemical pre-treatment showed retention of firmness (84.19%), vitamin C (89.38%), total phenolic content (85.67%) and antioxidant capacity (94.04%) which was significantly higher than the untreated samples. Also, inhibition of polyphenol oxidase, peroxidase, amylase, cellulase, and pectinase was found to be more than 65% till the 10th day. Thus, the present study describes the potential of chemical pre-treatment to extend the shelf-life of cashew apples and its utilization for food product development can be explored. [ABSTRACT FROM AUTHOR]

The paper is focused on steel surface processing to ensure an improved adhesion of applied powder layer. Mechanical pre-treatment, chemical pre-treatment and their combination were used to compare their results with each other and to find out the pre-treatment that affected the final outcome the most. The final score was determined by the grid method. The outcome displayed a huge mutual dependency between the result and a kind of various surface treatments. The method with no pre-treatment was by far the worst, followed by the mechanical pre-treatment only, followed by the chemical pre-treatment only, and finally by their combination. The time of blasting affects the final outcome. Through the grid method, coating thickness, and aesthetic test it was confirmed that an optimal blasting time of 5 min provides the best outcome.

Italian law requires bioplastics to meet precise degradability criteria under aerobic conditions to be treated with Organic Fraction Municipal Solid Waste (OFMSW) but does not provide specific controls on anaerobic degradation capacity. The result is longer composting times for bioplastics than OFMSW. The marketing and use of biodegradable single-use products, such as shopper bags, sidesteps the problem of using common plastics without completely solving it. Therefore, there is a need to identify technological solutions that allow for the complete degradation of biodegradable plastics without the need to modify the process in place in organic waste treatment plants. For this purpose, on biodegradable plastics composed mainly of starch and PBAT, anaerobic digestion tests were carried out to assess whether the degradation kinetics are consistent with the digestion hydraulic retention time of the organic fraction. Alongside this process, pre-treatment tests involving chemical hydrolysis and commercial enzymes were conducted. The tests were performed on laboratory and pilot scales, using organic matter and culture medium for methanogenic bacteria growing also in comparison with Clostridia consortia and both in mesophilic and thermophilic conditions. During the tests, samples were collected after 30 and 55 days of reaction. Microplastic content was analysed in terms of weight loss and presence of PBAT building blocks: adipic acid, terephthalic acid, and 1,4-butanediol. The results showed that both types of pre-treatments increase the degradation yield of bioplastics at different processing times. These results lead the way for the prospect that pre-treated biodegradable plastics can be delivered along with organic waste to existing anaerobic digestion and could increase the quantities normally handled in the aerobic composting plants. [ABSTRACT FROM AUTHOR]

BACKGROUND: Pyrolysis process is one of the most effective recycling methods due to its ability to recover products like gas, oil and char with oil being the major/important product. The shortcomings of waste tyre‐derived oil from the conventional pyrolysis process are that the oil contains high amounts of sulfur and polycyclic aromatic hydrocarbons (PAHs) and has a pungent smell, which makes it difficult to utilize further. The aim of this study is to investigate the effect of chemical pre‐treated waste tyre rubber crumb‐derived oil versus conventional waste tyre oil. The instrumentation utilized in this study was to solely investigate the shortcomings of waste tyre pyrolysis (high sulfur and PAH content and also high temperature required for waste tyre pyrolysis). RESULTS: The results showed a reduction in amounts of both sulfur and PAHs in treated waste tyre‐derived oil by about 83% and 77% respectively. Also, there was a reduction in initial pyrolysis temperature for the treated waste tyre crumb as compared to untreated waste tyre crumb: a temperature range of 96–115 °C for treated waste tyre crumbs as compared to 300–400 °C for untreated waste tyre crumbs. CONCLUSIONS: The success of this study means the production of quality oil at a low temperature with lower amounts of PAHs and sulfur and less odour, plus the possibilities of it being used as a petroleum fuel or for extraction of important compounds like benzene, toluene, xylene, limonene and C12–C20 acids. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Cow dung is generally used as the feedstock material for the anaerobic digestion to produce biogas. A selection of alternate biomass material is needed to reduce the consumption or to eliminate the use of cow dung. Recently, cottonseed hull has been considered as the primary substrate to produce biogas. In this paper, the effect of biogas production on anaerobic co-digestion of CD with pre-treated CSH using sulfuric acid, hydrochloric acid, hydrogen per oxide, and acetic acid is investigated. The concentration of each acid has been varied as 1%, 2%, and 3%. In addition, the two alkaline, namely, sodium hydroxide and calcium hydroxide, are used at different concentrations of 4%, 6%, and 8%. The biogas yield obtained from the mono-digestion of pre-treated CSH and the co-digestion of CD with chemically treated CSH at the ratio of 75:25 (CD: CSH) using the experimental results are compared. The enhancement of biogas production from the batch reactors at mesophilic temperature where the cow dung is mono- and co-digested with acid-treated and alkaline-treated cotton seed hull are observed and compared. The maximum biogas yield is achieved for the treated CSH at the concentration of 6% NaOH that offers 13-fold improvement over untreated CSH during mono-digestion. Whereas in co-digestion, it achieved a 6-fold improvement over untreated CSH with the ratio of 75:25 at the concentration of 6% Ca(OH)2. [ABSTRACT FROM AUTHOR]

Cattle manure usually contains a proportion of carbohydrates in the form of organic residues from incompletely digested feed and farm husbandry practices. These are not usually available for biogas production due to the long fermentation time. This paper investigates the optimal application of alkali, NaOH and KOH and mechanical pre-treatments to improve the degradation of the lignocellulosic content and the potential biogas yields from a local farm in Bavaria, Germany. Parameters such as temperature, pH, soluble chemical oxygen demand, organic acids, dry matter and volatile solids were analysed for this purpose. Alkali pre-treatments in 0.2, 0.1 and 0.05 M NaOH concentrations were tested in single mode and combined with shredding in batch experiments. The maximum increment of the soluble chemical oxygen demand during the pre-treatments took place during the first 50 h of experimentation, and it showed an improvement of 10,060.0 ± 8% mg/L s COD after the application of 0.2 M NaOH compared to the untreated substrate, which had an initial value of 2145.0 ± 8% mg/L s COD. Pre-treatments with 0.1 and 0.05 M NaOH concentrations showed similar s COD increments, with an additional 6860.0 ± 8% mg/L s COD and 8505.0 ± 8% mg/L s COD, respectively. The pH values varied strongly after the addition of the pre-treatment chemicals, with a continuous pH of 12 by 0.2 M NaOH during the 7 days of pre-treatment. Batch biogas experiments were done by applying 0.05 M NaOH and 0.05 M KOH pre-treatments in single mode and combined with shredding. The chemically pre-treated substrates showed a faster biogas production with an advantage of 18 days in comparison to the untreated cattle manure by a biogas yield of 350.0 NL/kg VS. All experiments were done under mesophilic conditions. [ABSTRACT FROM AUTHOR]

The present work aims to enhance the mechanical properties, thermal stability, and water resistance behavior of hybrid Pinus/Shorea robusta wood particles reinforced epoxy composites employing the chemical pre-treatments. The hybrid wood composites were prepared by hand lay-up method keeping a constant of 25 wt% of wood particles concentration with equal proportions of Pinus and Shorea robusta wood particles. The performance of the hybrid wood composite was improved by improving the interfacial bonding between wood particles and epoxy resin by chemical pre-treatments of the wood particles using silane (APTES) with varying concentrations of 2, 4, and 6 wt% and alkali (NaOH) with varying concentrations of 5%, 10%, and 15%. The mechanical properties (namely, tensile, flexural, impact, and microhardness) and water absorption properties (namely, maximum water uptake and sorption, diffusion, and permeability coefficients) of the prepared hybrid wood composites were measured. The investigations include the study of thermal degradation and crystalline behavior using thermogravimetric analysis and X-ray diffraction analysis, respectively. It was observed that the mechanical properties, thermal stability, and water resistance and crystalline behavior of the hybrid wood composites were significantly enhanced after these pre-treatments. Further, it was concluded that silane pre-treated hybrid composite with 6 wt% concentration provided the best performance than untreated as well as alkali pre-treated wood composites. [ABSTRACT FROM AUTHOR]

Polyacrylonitrile-based pre-oxidized fibers with improved thermal stability, flame retardant, and mechanical properties were made from the pristine polyacrylonitrile fibers through chemical pretreatment followed by pre-oxidation in air. The morphological structure of the polyacrylonitrile-based pre-oxidized fibers was investigated by Fourier transfer infrared spectra, X-ray diffraction, scanning electron microscopy, and X-ray energy dispersive spectrometer. The changes of characteristic functional groups and chemical compositions confirmed the successful modification of the polyacrylonitrile fibers during pre-treatment. The grooves and cracks on the surface of polyacrylonitrile-based pre-oxidized fibers were remarkably decreased in comparison with that of pristine polyacrylonitrile fibers. The evolution of crystalline structure of the polyacrylonitrile fibers proved the occurrence of cyclization reactions during pre-oxidation. Meanwhile, thermal stability, flame retardant, and mechanical properties of polyacrylonitrile-based pre-oxidized fibers were also investigated by thermogravimetric analyzer, oxygen index meter, micro combustion calorimeter, and single fiber tensile tester, respectively. The results demonstrated that the polyacrylonitrile-based pre-oxidized fibers initially pre-treated by hydroxylamine hydrochloride, followed by monoethanolamine, had a high limiting oxygen index of 40.1 and breaking strength of 2.03 cN/dtex. The peak of heat release rate and total heat release of polyacrylonitrile-based pre-oxidized fibers decreased significantly while its charred residues increased, contributing to the improved flame retardant property. [ABSTRACT FROM AUTHOR]

Agar is a strongly gelling polysaccharide extracted from gracilarioids, which is processed through conventional alkaline pre-treatment and chemical bleaching. However, the use of chemical bleaching agents has associated health risks to humans and the environment. The aim of the present study was to determine the effects of photo-bleaching in combination with NaOH pre-treatments at 5, 10 and 15% concentrations on the physico-chemical properties of agar extracted from Gracilariopsis heteroclada. The results highlighted that the gel strength of photo-bleached agar extracts PBA-15 (1822.00 g cm−2), PBA-10 (1465.60 g cm−2), and PBA-5 (1067.70 g cm−2) were significantly higher than in either a commercially sourced agar reference sample (756.20 g cm−2) or a chemically bleached agar (390.94 g cm−2). The physico-chemical properties of PBA extracts fell within the acceptable limits of food-grade agar. Photo-bleached agar extracts (PBA-5, PBA-10, PBA-15) also exhibited a higher lightness (L*) and whiteness index (WI) which makes these agars ideal for microbiological use. This study demonstrated that photo-bleaching by solar irradiation improved the physico-chemical properties of agar from G. heteroclada without the use of a chemical bleaching agent. [ABSTRACT FROM AUTHOR]

The purpose of this study is to determine the influence of abrasive pre-treatments on plum drying time compared to the conventional ones. The mechanical pre-treatment examined included the abrasion at three different cylinder rotation times: 5, 10 and 15 min. The chemical pre-treatment under consideration included the immersion of plums in alkaline solution (KOH) of different concentrations (0.5, 1 and 1.5% (v / v)) at 60 °C for one minute. The thermal treatment performed included the immersion of fruits in distilled water at 60 °C for one minute. As a control (untreated) sample, fruits with waxy lawyers were used. According to the results obtained, the drying time of plums was significantly reduced compared to the control sample (97 h): in the samples treated with distilled water (thermal treatment) drying time was reduced by 21 h, whereas the drying time reduction of up to 68 h was reorded using a KOH solution of 1.5%. In the samples pre-treated by abrasion for 15 min, the drying time recorded was also reduced by 68 h compared to the control samples, thus proving the exceptional efficiency of abrasive pre-treatment in plum drying.

The recalcitrant nature of native wheat straw (WS) biomass results from cellulose, lignin, hemicellulose and some amount of protein embedded together in a composite structure causing poor adhesion to a polymer matrix composite. Adequate pre-treatment can curtail the recalcitrance structure of WS and enhance the susceptible cellulose area to synthesize a green composite. This paper examined the effect of various chemical pre-treatment procedures in improving surface morphology of wheat straw. Moreover, polystyrene (PS), PS (60 wt%)/native WS (40 wt%), PS (60 wt%)/NaOH-treated WS (40 wt%), PS (60 wt%)/HCl-treated WS (40 wt%), and PS (60 wt%)/H2SO4-treated WS (40 wt%) composite films were prepared using solution casting method. The changes in crystalline structure, hydrophobicity, water vapor migration rate, and thermal and mechanical stabilities of synthesized bio-composites were examined. From the results it can be concluded that the alkali-treated WS is highly compatible with the PS and can be used to synthesize a biodegradable composite film for various industrial green packaging applications. [ABSTRACT FROM AUTHOR]

Polyacrylonitrile-based pre-oxidized fibers with improved thermal stability, flame retardant, and mechanical properties were made from the pristine polyacrylonitrile fibers through chemical pretreatment followed by pre-oxidation in air. The morphological structure of the polyacrylonitrile-based pre-oxidized fibers was investigated by Fourier transfer infrared spectra, X-ray diffraction, scanning electron microscopy, and X-ray energy dispersive spectrometer. The changes of characteristic functional groups and chemical compositions confirmed the successful modification of the polyacrylonitrile fibers during pre-treatment. The grooves and cracks on the surface of polyacrylonitrile-based pre-oxidized fibers were remarkably decreased in comparison with that of pristine polyacrylonitrile fibers. The evolution of crystalline structure of the polyacrylonitrile fibers proved the occurrence of cyclization reactions during pre-oxidation. Meanwhile, thermal stability, flame retardant, and mechanical properties of polyacrylonitrile-based pre-oxidized fibers were also investigated by thermogravimetric analyzer, oxygen index meter, micro combustion calorimeter, and single fiber tensile tester, respectively. The results demonstrated that the polyacrylonitrile-based pre-oxidized fibers initially pre-treated by hydroxylamine hydrochloride, followed by monoethanolamine, had a high limiting oxygen index of 40.1 and breaking strength of 2.03 cN/dtex. The peak of heat release rate and total heat release of polyacrylonitrile-based pre-oxidized fibers decreased significantly while its charred residues increased, contributing to the improved flame retardant property. [ABSTRACT FROM AUTHOR]

The quality of dried fig was compared by treating blanched figs with potassium metabisulfite, NaCl, ascorbic acid (AA) at various concentrations (2, 3, 4%) and sucrose solution (30, 40, 50%). In comparison of results for functional attributes, T5 (blanching +4% AA dipped for 10 min) stood prominent in retaining higher ascorbic acid, phenolics and antioxidant activity followed by T4 (blanching +3% AA dipped for 10 min) and T3 (blanching +2% AA dipped for 10 min). However, higher fibers and total sugars were found in T8 (blanching +50% sucrose dipped for 30 min) and T7 (blanching +40% sucrose dipped for 30 min). Eventually, sensory evaluation of the stored samples demonstrated best scores for the osmotically dehydrated fig with 30 and 40% sucrose prior to cabinet drying. Overall, the results of present investigation have significant contribution to the food industry. Of note the shelf life and stability of fig could be enhanced upon bringing the result of this finding in practice. [ABSTRACT FROM AUTHOR]

Wheat gluten (WG) and potato protein (PP) were modified to a basic pH by NaOH to impact macromolecular and structural properties. Films were processed by compression molding (at 130 and 150 °C) of WG, PP, their chemically modified versions (MWG, MPP) and of their blends in different ratios to study the impact of chemical modification on structure, processing and tensile properties. The modification changed the molecular and secondary structure of both protein powders, through unfolding and re-polymerization, resulting in less cross-linked proteins. The β-sheet formation due to NaOH modification increased for WG and decreased for PP. Processing resulted in cross-linking of the proteins, shown by a decrease in extractability; to a higher degree for WG than for PP, despite higher β-sheet content in PP. Compression molding of MPP resulted in an increase in protein cross-linking and improved maximum stress and extensibility as compared to PP at 130 °C. The highest degree of cross-linking with improved maximum stress and extensibility was found for WG/MPP blends compared to WG/PP and MWG/MPP at 130 °C. To conclude, chemical modification of PP changed the protein structures produced under harsh industrial conditions and made the protein more reactive and attractive for use in bio-based materials processing, no such positive gains were seen for WG.

One of the bottlenecks in the industrial production of cellulose nanofibrils (CNFs) is its high energy cost. Several pretreatments have been researched in an attempt to reduce costs. A promising strategy is phosphorylation, which has the advantages of being low cost and non-toxic. This study aimed to produce CNFs with lower energy consumption and better characteristics, such as improved barrier properties and thermal resistance, by phosphorylation using different reagent concentrations and heat treatment times. For this, bleached Eucalyptus fibers were heat-treated at 150 °C using fiber/diammonium phosphate/urea molar mass ratios of 1:1:1 and 1:2:2 for 5, 20, and 40 min. Subsequently, the material was subjected to mechanical fibrillation to produce CNFs. Fiber quality was analyzed using thermogravimetry, Fourier-transform infrared spectroscopy, and X-ray diffraction. CNF samples were characterized using scanning electron microscopy, turbidimetry, contact angle analysis, wettability analysis, surface energy measurement, confocal microscopy, roughness analysis, mechanical tests, and transparency analysis. Energy consumption was measured during fibrillation. Phosphorylation was efficient in reducing energy consumption and resulted in the production of higher-quality CNFs as compared with no pretreatment. The best pretreatment conditions were molar mass ratio of 1:1:1 and time of reaction of 20 min [Display omitted] • Phosphorylation leave a less energy consumption during nanocellulose production. • Phosphorylation led to an increase in the degree of fibrillation of nanocellulose. • Nanopapers with phosphorylation are more transparent, smooth, and hydrophobic. [ABSTRACT FROM AUTHOR]

Poly(vinyl alcohol) (PVA) blended with natural chitosan (CH) was selected as matrix for the production, by solvent casting in water, of nanocomposite films containing cellulose nanocrystals (CNC) extracted from barley residues, that were introduced in PVA_CH systems as reinforcement phases. Cellulose nanocrystals were successfully extracted from both barley straw and husk by applying two different approaches, a chemical alkaline and an enzymatic pre-treatment, followed by acidic hydrolysis. The results evidenced the major effectiveness of the enzymatic pre-treatment on the quality of obtained CNC; nevertheless, all the different typologies of nanocrystals were added to the polymers and the morphological, optical, mechanical response, thermal and migration characteristics were investigated, whereas antimicrobial assay were carried out to evaluate the bactericidal effect induced by chitosan presence. The results indicated that chitosan reduced the optical transparency and the mechanical response of PVA matrix, whereas its combination with CNC (especially when extracted by enzymatic treatment and added at a higher content) was able to modulate the optical properties, the mechanical and thermal responses. Moreover, inhibitions on fungal and bacterial development were detected for PVA_CH_CNC ternary systems, suggesting their protective function against microorganisms contamination. [ABSTRACT FROM AUTHOR]

Anaerobic digestion (AD) is a useful method for producing renewable energy/biofuel. Today, biogas production uses a large amount of energy crops (EC), with the effect of increasing AD costs and creating conflict between food/feed vs. energy use. A partial solution to this might be the substitution of EC with agricultural wastes, e.g. straw. Straw and corn stover are widely available in the world and approximately 1600 million Mg year − 1 of these substrates are available. Straw can be useful used for biogas production but its characteristics limit its performance so that sometimes the energetic balance can be negative. In this review, the limits for the conversion of this substrate into biogas were investigated and solutions/proposals for getting higher straw biogas production performance are reported. In addition, energetic balances for untreated and pre-treated substrates are reported, giving indicative evaluations of the sustainability of straw and corn stover use for biogas production. [ABSTRACT FROM AUTHOR]

The removal of Cu2+ ions by adsorption using biomass derived from Zalacca edulis peel was studied in a batch system.The effects of pH and chemical pre-treatment of the biomass by the use of CaCl2 with different thermal conditions and initialconcentrations were also determined. The results showed that chemical pre-treatment by CaCl2 enhanced the capacity of Cu2+ions biosorption. The equilibrium sorption data of untreated Zalacca edulis peel and Zalacca edulis peel pre-treated withCaCl2 were fitted well by both Langmuir and Freundlich isotherms equations. According to the Langmuir equation, the maximumuptake of Cu2+ ions by the use of Zalacca edulis peel pre-treated with CaCl2 was found to be 27.03 mg g-1 at pH 5. Therate of adsorption was found to conform to pseudo-second order kinetics with good correlation. The binding between heavymetal Cu2+ ions and chemically pre-treated biosorbent was confirmed by the use of scanning electron microscope combinedwith energy dispersive X-ray analysis and electron probe microanalyser.

Novel gluten based bionanocomposites reinforced with cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC) extracted from sunflower stalks by respectively a steam explosion treatment and a hydrolysis procedure, were prepared by casting/evaporation. The extracted cellulose nanomaterials, both CNC and CNF, were embedded in gluten matrix and their effect was investigated. Morphological investigations highlighted that gluten based bionanocomposites showed a homogenous morphology, the absence of visible cellulose nanoreinforcements, and the presence of holes for Gluten_CNF nanocomposites. Gluten_CNF showed a reduction of water vapour permeability coefficients but the values are higher respect to gluten reinforced with CNC. This behaviour could be related to the ability of CNC to increase the tortuous path of gas molecules. Moreover, the results from thermal, mechanical and barrier properties confirmed the strong interactions obtained between CNC and gluten matrix during the process. The study suggested the possibility to re-valorise agricultural wastes with potential applications as reinforcement in polymer matrix bionanocomposites. [ABSTRACT FROM AUTHOR]

An attempt was made to quantify the contribution of chemical pre-treatment on the color changes of apple slices during hot air drying. The monitored color attributes of apple slices were computed real time at drying air temperatures of 50, 60, and 70 °C. The apple slices dried in a computer vision system (CVS) assisted-hot air dryer both with and without pre-treatment. The quantities of measured color parameters for pre-treated (P.T.) samples were subtracted from the values obtained for untreated (U.T.) samples at the same water content. For this purpose, an artificial neural network was developed and used satisfactorily for mapping out the color parameters of P.T. samples at calculated moisture ratio for U.T. sample to compute the physio-chemically significant difference. From the results, it can be derived that a CVS seems to be a promising tool when it comes to detecting and monitoring the effects of various pre-treatments on being-processed foodstuffs . [ABSTRACT FROM AUTHOR]

The aim of this work was to study the effect of the solvent N-methylmorpholine-N-oxide (NMMO) to pre-treat Nannochloropsis oculata before the anaerobic digestion process. The results indicated that the pre-treatment affects the characteristics of the cell wall, which consequently becomes more susceptible to the microorganisms attack during anaerobic digestion. The methane production was increased by 43% after the pre-treatment, from 238 ± 6 mL CH4 /g VS until 339 ± 4 mL CH4 /g VS . On the contrary, the methane production from Chlorella vulgaris decreased after the pre-treatment from 251 ± 4 mL CH4 /g VS to 231 ± 3 mL CH4 /g VS . The failure on the pre-treatment was attributed to the particular characteristics of the substrate in consequence of a previous drying step. [ABSTRACT FROM AUTHOR]

This paper aims at presenting a solution for the treatment of industrial waste water, resulted from the process of chemical pretreatment in the electrostatic painting industry, which can also supply water decontamination, thus preventing environmental destruction. The proposed technological process can be optimized by redesigning the pretreatment process by changing the path of the waste water and redirect it in the system created within the company, based on the observations noted during two years of sampling and testing. The results have been confirmed by the fact that through the implemented system, the waste water, can be efficiently cleaned and re-entered in the work process without affecting the quality of the process the pretreated products. By using this system lower production costs were achieved. This was possible by reducing the amount of water used from the distribution network, as well as by reducing the amount of chemicals needed for the pretreatment of contaminated water. [ABSTRACT FROM AUTHOR]

Biological hydrogen production using palm oil mill effluent (POME) as a carbon source through dark fermentation process has been suggested to be a promising bioenergy potential and enacts as alternative renewable energy source. Results have indicated that among various 1.5% (w/v) chemical pre-treatments (sodium hydroxide, NaOH; hydrochloric acid, HCl; sulphuric acid, H 2 SO 4 ; phosphoric acid, H 3 PO 4 and nitric acid, HNO 3) on POME, using H 3 PO 4 would generate maximum biohydrogen production of 0.193 mmol/L/h, which corresponded to a yield of 1.51 mol H 2 /mol TC consumed with an initial total soluble carbohydrate concentration of 23.52 g/L. Among H 3 PO 4 concentrations (1%–10%), the soluble carbohydrate content and the biohydrogen produced was highest and increased by 1.70-fold and 2.35-fold respectively at 2.5% (w/v), as compared to untreated POME. The batch fermentation maximum hydrogen production rate and yield of 0.208 mmol/L/h and 1.69 mol H 2 /mol TC consumed were achieved at optimum pre-treatment conditions of pH 5.5 and thermophilic temperature (60 °C). This study suggests that chemical pre-treatment approaches manage to produce and improve the carbohydrate utilisation process further. Continuous fermentation in CSTR at the optimum conditions produce heightened 1.5-fold biohydrogen yield for 2.5% H 3 PO 4 at 6 h HRT as compared to batch scale. Bacterial community via next-generation sequencing analysis at optimum HRT (6 h) revealed that Thermoanaerobacterium thermosaccharolyticum registered the highest relative frequency of 20.24%. At the class level, Clostridia , Bacilli , Bacteroidia , Thermoanaerobacteria, and Gammaproteobacteria were identified as the biohydrogen-producing bacteria in the continuous system. Insightful findings from this study suggest the substantial practical utility of dilute chemical pre-treatment in improving biohydrogen production. [Display omitted] • Acid pre-treatment of POME enhanced biohydrogen production than alkaline treatment. • 2.5% (w/v) H 3 PO 4 pre-treatment at 20 min increased total sugar content by 2-fold. • pH 5.5 and temperature of 60 °C represented optimum pre-treatment conditions. • CSTR at 6-h HRT produced HY of 2.25 mol H₂ /mol TC from pre-treated POME. • Biohydrogen attributed to genera Thermoanaerobacterium , Clostridium and Bacillus. [ABSTRACT FROM AUTHOR]

The pre-treatment step of lignocellulosic ethanol production is recognised as the most energy intensive part of the overall process. Key objectives are thus that pre-treatments should operate effectively at low to moderate temperatures and at high percentage solids, in order to minimise energy inputs. Chemical pre-treatment of BSG using alkaline reagents, at moderate process temperatures, was optimised in terms of sugar release following enzymatic saccharification of the pre-treated residues. An excess of Celluclast ® cellulase enzyme was used to compare various pre-treatments in terms of the % of theoretical sugars that could be liberated. Using alkaline peroxide (5% H 2 O 2 /NaOH at pH 11) up to 87% of the theoretical glucose yield (based on composition of the pre-treated residue) was attained following pre-treatment of BSG at 25% (w/v) solids loading for 5 h at 100 °C. Pre-treatment using 5% NaOH at 25% (w/v) solids loading for 12 h at 50 °C liberated 92% of theoretical glucose This pre-treatment remained effective with process times as short as 2 h (ca. 70% of theoretical glucose). For NaOH pre-treatments the extent of lignin removal from pre-treated residues broadly correlated with the efficacy of the pre-treatment in terms of final saccharification yields. However, for alkaline peroxide pre-treatments no such correlation was observed. Saccharified BSG was prepared following treatment with the optimised NaOH or alkaline peroxide pre-treatments and the resultant hydrolysates fermented with Saccharomyces cerevisiae . Fermentation performance was superior for the NaOH pre-treated samples relative to alkaline peroxide generated feedstocks with shorter lag phases and faster attenuation rates. Mean ethanol concentrations of ca. 17.3 g/L and 8.4 g/L were achieved for the NaOH and alkaline peroxide fermentations respectively which corresponded to 81% and 43% of theoretical ethanol yields. [ABSTRACT FROM AUTHOR]

• Biomethane is one of the cleaner energy alternatives to replace other fuels. • Anaerobic digestion of lignocellulosic biomass into biomethane production is reviewed. • The environmental and economic impact over the biomethane production is reviewed. • Different pre-treatment methods were adopted for the generation of sustainable green energy is reviewed. Biomethane is one of the cleaner energy alternatives to replace natural, fossil fuels and has emerged incredibly along the years for its wider implementation in most parts of the globe. This review outlook the works which were made effectively to stabilize the biogas production via anaerobic digestion (AD) for the lignocellulosic biomass with an effective pre-treatment method. This review is eloquent in the wider acceptance of the pre-treatment methods applied on lignocellulosic feed-biomass for the biomethane production with AD process, which relies on the complete structural breakdown of the lignocellulosic biomass. Pre-treatment can be classed as physical, chemical and biological methods. The physical methods such as mechanical and liquid hot water could increase the biomass properties whereas irradiation and steam explosion methods could able to enhances the hydrocarbons in the biomethane during anaerobic digestion process. The chemical pre-treatment methods basically eliminate the toxic metals in the biomass and therefore improve the energy value in the produced biomethane. The biological methods could increase the process stability by completely degraded the biomass to biomethane. The environmental and economic impact over the biomethane production and its pre-treatment methods is briefed to understand the importance and the need for anaerobic biomethane production system in the future. This study would open new insight for various pre-treatment methods employed in the production of sustainable green energy from lignocellulosic biomass through the AD process. Thus, leading to cheaper and eco-friendly production of green energy. [ABSTRACT FROM AUTHOR]

Dealing with the digestate liquid phase from biogas stations has become a problem, due to the rapidly increasing number of biogas stations, tighter legislation, and the nature of the digestate that remains after anaerobic digestion of a biodegradable feedstock. The present solution is a farmland disposal. Standard biological treatment is not applicable because of the extremely high Chemical Oxygen Demand (COD). The method proposed here places chemical pre-treatment of the digestate before the biological stage. This reduces the COD to an acceptable level, from about 100 kg m −3 to about (2–4) kg m −3 . The separated water phase can then be treated in a standard biological aerobic wastewater treatment plant. The chemical sludge can be treated by composting, together with the biological sludge. With the use of proper additives, a digestate material can be produced that raises the fertilizing and adsorption properties of the soil. [ABSTRACT FROM AUTHOR]

In the present study a comparison of two different surface pre-treatments and their influence on a subsequent surface metallization were studied. Standard electroless copper deposition involving initial etching in mild acid is thoroughly compared with the process where plasma pre-treatment replaced the mild acid etch. Specific surface co-planar type of dielectric barrier discharge was employed to provide a technologically feasible plasma pre-treatment of composites of carbon reinforced epoxy polymers. Results demonstrated both approaches being able to achieve excellent adhesion of final coating. In contrast to standard chemical pre-treatment, plasma pre-treatment is associated with changes of initial composite surface chemistry only. The purpose of plasma action in polymer pre-treatment is to provide ample amount of active surface sites where Pd ions can be attached effectively. XPS analysis revealed, that Pd atom on plasma treated surface takes the form of its oxide compounds PdO and PdO 2 preferably, while its form on the surface of standard chemical pre-treatment is mostly metallic-Pd. [ABSTRACT FROM AUTHOR]

The aim of this research work was to study the surface properties and sorption characteristics of differently treated regenerated cellulose fabrics. Surface modifications of viscose, modal and lyocell samples caused by using standard chemical pre-treatment procedures were compared to an alternative activation procedure by applying low pressure oxygen plasma treatment. The elemental chemical composition of the modified fabric surfaces was investigated using X-ray photoelectron spectroscopy (XPS), while hydrophilic/hydrophobic properties were evaluated by determining the water contact angles, as well as thoroughly analysed using Owens–Wendt surface energy (SFE) and surface polarity investigations.Standard chemical and also plasma treatments changed the surface chemistry of cellulose. Bleaching and alkaline treatments increased the surface carboxylic acid content by approximately 4.8% while plasma treatment increased it by approximately 9.7%. As a consequence, higher hydrophilicity arises as proved by water contact angle decrease; i.e. 24% (61°) after standard chemical treatments and 70% (20°) after plasma treatment. Both chemical treatments increase the SFE and polar components, while the reduction of dispersive components was less pronounced. The oxygen activation treatment has the greatest influence on the SFEs of the samples as well as on polarity of the samples. [ABSTRACT FROM PUBLISHER]

In this study, various chemical and advanced oxidation processes were tested for enhancement of anaerobic biodégradation of olive mill effluent (OME). The experiments were carried out in a 20 L lab-scale ACF reactor packed with cross-flow filter material made of water-resistant cardboard with a specific surface area of ∼300 m2 m3. The ACF reactor was operated at chosen OLR conditions and fed with different pre-treated OME samples for 240 days (717 days in total). All pretreatment options used in this study improved the anaerobic biological degradation in terms of COD, phenolics and color removal efficiencies. Best effluent quality (5700±250 mg COD per liter) was obtained by using the Fenton process as a pre-treatment. This effluent value is still higher than the official discharge limit for COD (4000 mg COD per liter) in Turkey. Therefore, additional final treatment (e.g. membrane filtration) may be required before discharging into the sewer line. [ABSTRACT FROM AUTHOR]

The removal of Cu2+ ions by adsorption using biomass derived from Zalacca edulis peel was studied in a batch system. The effects of pH and chemical pre-treatment of the biomass by the use of CaCl2 with different thermal conditions and initial concentrations were also determined. The results showed that chemical pre-treatment by CaCl2 enhanced the capacity of Cu2+ ions biosorption. The equilibrium sorption data of untreated Zalacca edulis peel and Zalacca edulis peel pre-treated with CaCl2 were fitted well by both Langmuir and Freundlich isotherms equations. According to the Langmuir equation, the maximum uptake of Cu2+ ions by the use of Zalacca edulis peel pre-treated with CaCl2 was found to be 27.03 mg g-1 at pH 5. The rate of adsorption was found to conform to pseudo-second order kinetics with good correlation. The binding between heavy metal Cu2+ ions and chemically pre-treated biosorbent was confirmed by the use of scanning electron microscope combined with energy dispersive X-ray analysis and electron probe microanalyser. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the results of olive oil mill wastewater (OOMW) using physicochemical pre-treatment and Fenton and Fenton-like processes are presented. On the other hand, acute toxicities of raw, physicochemical pre-treated, and Fenton and Fenton-like oxidations applied samples of OOMW on activated sludge microorganisms using respiration inhibition test (ISO 8192) are presented. Chemical pre-treatment (acid cracking and coagulation–flocculation) positively affected the biodegradability and inhibition on activated sludge was considerably removed (>67% COD and >72% total-phenol removal). Fenton and Fenton-like processes showed high COD (>80%) and total-phenol (>85%) removal performance on evaluated effluents. Inhibitory effect of Fenton-like reagents applied samples on activated sludge mixture was considerably removed. In addition to the toxicity, total-phenol and COD removal efficiencies of applied processes, their associated operating costs were also determined in this paper. [Copyright &y& Elsevier]

The physicochemical characteristics of three Brazilian peats were investigated using elemental analysis, scanning electron microscopy (SEM), X-ray diffractometry (XRD) and studies of Cr(III) biosorption based on adsorption isotherms. Adsorption of Cr(III) by in natura peat from Santo Amaro das Brotas (Sergipe State) was much greater than by peats from either Ribeirão Preto (São Paulo State) or Itabaiana (Sergipe State), with adsorption capacities (q) of 4.90±0.01, 1.70±0.01 and 1.40±0.01mgg−1, respectively. Pre-treatments with HCl and NaOH+HCl reduced adsorption by the Santo Amaro das Brotas peat, showing that adsorption efficiency was associated with the amount of organic matter present. Conversely, increase in the mineral content following pre-treatment increased adsorption of Cr(III) by the Ribeirão Preto and Itabaiana peats. Highest adsorption (retention >95.0%) was achieved at equilibrium pH 4.0 using the Santo Amaro das Brotas peat. Experimental data for the adsorption of Cr(III) from aqueous solution onto this peat were fitted to the Langmuir equation, from which an equilibrium adsorption capacity, q max, of 5.60mgg−1 was obtained, which was close to the experimentally determined value. [Copyright &y& Elsevier]

The employment of macroalgal biomass in anaerobic digestion (AD) systems could provide an alternative and renewable energy source and overcome the concern of algal influx. Sargassum fulvellum macroalgae was applied in the batch digesters as raw algal biomass (M raw), enzymatically treated biomass (M enz), reduced-sized biomass (M red), chemically pretreated reduced-sized biomass with 0.36 mL g−1 VS (M acid1) and 0.18 mL g−1 VS (M acid2) of 2 M HCl and with 0.09 mL g−1 VS (M alkali1) and 0.04 mL g−1 VS (M alkali2) of 6 M NaOH. The results of this study indicated that the biologically treated digester (M enz) enhanced the methane yield to 186.60 mL g−1VS, which corresponds to 116.64% and 33.48% increases over those in the M red and M raw , respectively. Additionally, chemical pre-treatments of Sargassum fulvellum enhanced the methane outcome by 15.11%, 6.53%, 45.65%, and 37.01% for M acid1 , M acid2 , M alkali1 , and M alkali2 , respectively, compared with the M red. This study emphasized that the utilization of raw untreated Sargassum fulvellum macroalgae through the thermophilic AD system was better than chemical and mechanical pre-treated feedstocks, which verified the eco-benefits and sustainable biomass management approach. The gas recovery of raw macroalgae can be further improved through the supplementation with a cellulase enzyme. [Display omitted] • Potential of biogas production from Sargassum fulvellum macroalgae was explored. • Biological treatment of macroalgae enhanced the methane yield to 116.64%. • Alkali pretreatment improved the gas yield to 45.65%. • Biological treatment of macroalgae was the optimum and reasonable method. • Utilization of macroalgae attained eco-benefits and sustainable bioenergy production. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this work was to study the influence of ethyl tris-2-methoxyethoxy silane (compound belonging to the class of silanes referred to as silicon tripodands) on the formation of passive layer (often called solid electrolyte interphase) on the electrode made of highly graphitic material during first reduction in propylene carbonate-based (PC) electrolytes. The podand molecules were introduced to the system as additives (co-solvents) to PC and as surface pre-treatment agents for graphite electrodes. It was found that in the presence of podand graphite anode functions properly in PC-containing electrolytes and no detrimental solvent co-intercalation is observed. These phenomena have been ascribed to partial hydrolysis of podand molecules on the graphite surfaces, leading to the formation of a two-dimensional polymeric network via Si–O–Si bonds. Electrochemical characterization involved galvanostatic charging/discharging and cycling voltammetry experiments. On the basis of the presented findings new industrially viable, low-cost, low-temperature Li-ion cell designs can be developed. [Copyright &y& Elsevier]

Many novel treatment technologies, usually representing a pre-treatment prior to the biological degradation process, have been developed in order to improve the recycling and reuse of sewage sludge. Among all the methods available, a chemical (alkaline) and a thermal treatment have been considered in this study. The behaviour of 13 substances belonging to different therapeutic classes (musks, tranquillisers, antiepileptic, anti-inflammatories, antibiotics, X-ray contrast media and estrogens) has been studied during the anaerobic digestion of sewage sludge combined with these pre-treatments (advanced operation) in comparison with the conventional process. Two parameters have been analysed: the temperature (mesophilic and thermophilic conditions) and the sludge retention time. While organic matter solubilization was higher with the alkaline process (55–80%), no difference between both pre-treatments was observed concerning volatile solids solubilization (up to 20%). The removal efficiencies of solids and organic matter during anaerobic digestion ranged from 40–70% and 45–75%, respectively. The higher removal efficiencies of pharmaceuticals and personal care products were achieved for the antibiotics, Naproxen and the natural estrogens (>80%). For the other compounds, the values were in the range 20–70%, except for Carbamazepine, which was not removed at any condition tested. [ABSTRACT FROM AUTHOR]

Abstract: The biomass of the brown seaweed, Ecklonia sp., is capable of reducing Cr(VI) to Cr(III). However, very little is known about the mechanism of Cr(VI) reduction by the biomass. The aims of the present investigation were to enhance the Cr(VI)-reducing capacity of the biomass using various chemical treatments and to elucidate the mechanisms governing Cr(VI) reduction. Among the various chemical treatments, acid-treatment showed the best performance with regards the improvement of Cr(VI) removal from the aqueous phase, while organic solvent-treatment significantly improved the removal efficiency of total Cr in the equilibrium state. Based on FTIR study, the biomass was subjected to chemical modification of its amino and carboxyl groups, to examine their roles in the Cr(VI) removal from the aqueous phase. Methylation of the amino group significantly decreased the Cr(VI) removal rate, but amination of the carboxyl group significantly increased the Cr(VI) removal rate. Meanwhile, esterification of the carboxyl group and carboxylation of the amino group decreased the Cr(VI) removal rate, but the former showed a more negative effect than the latter. These findings indicated that the amino and carboxyl groups take part in the Cr(VI) removal from the aqueous phase. In conclusion, mechanisms for direct and indirect Cr(VI) removal are proposed, and some aspects for the application of this biomass to Cr(VI) detoxification are discussed. [Copyright &y& Elsevier]

Chemical treatment previous to biological treatment of p-coumaric acid may represent a strategy in order to improve its biodegradability. In this work, anaerobic biodegradation of synthetic waters containing this compound and pre-oxidized waters by ozonation was studied. The critical and optimum retention times for the reactor fed with p-coumaric acid were 15.9 and 20 days, respectively. Under the optimal operational conditions removal percentage ranged from 85 to 90%. The bioreactor for ozonated p-coumaric acid was operated at a constant hydraulic retention time (HRT) of 25 days, since lower HRT caused its destabilization and during period of more stability the percentage of removal varied between 71 and 84%. Thus, the use of the ozonation as chemical pre-treatment did not enhance biological degradation of p-coumaric acid. On the other hand, microorganisms able to use p-coumaric acid (or its major intermediates produced from the ozonation treatment), were isolated at maximum tolerated concentrations of these compounds. Since the ozonation as chemical pre-treatment did not improve p-coumaric acid biodegradation, the enrichment of these isolated strains could be the most adequate strategy to enhance the biological degradation of p-coumaric acid. [Copyright &y& Elsevier]