Sulfuric Acid Treatment Research Articles

Characterization of unsubstituted and methylated polycyclic aromatic hydrocarbons in settled dust: Combination of instrumental analysis and in vitro reporter gene assays and implications for cancer risk assessment

Concentrations of 34 unsubstituted and methylated polycyclic aromatic hydrocarbons (PAHs and Me-PAHs) and AhR-mediated activities in settled dust samples were determined by a combination of gas chromatography–mass spectrometry and an in vitro reporter gene assay (PAH-CALUX). The levels of Σ34PAHs and bioassay-derived benzo[a]pyrene equivalents (CALUX BaP-EQs) were significantly higher in workplace dust from informal end-of-life vehicle dismantling workshops than in common house dust and road dust. In all the samples, the theoretical BaP-EQs of PAHs (calculated using PAH-CALUX relative potencies) accounted for 28 ± 19% of the CALUX BaP-EQs, suggesting significant contribution of aryl hydrocarbon receptor (AhR) agonists and/or mixture effects. Interestingly, the bioassay-derived BaP-EQs in these samples were significantly correlated with not only unsubstituted PAHs with known carcinogenic potencies but also many Me-PAHs, which should be included in future monitoring and toxicity tests. The bioassay responses of many sample extracts were substantially reduced but not suppressed with sulfuric acid treatment, indicating contribution of persistent AhR agonists. Cancer risk assessment based on the CALUX BaP-EQs has revealed unacceptable level of risk in many cases. The application of bioassay-derived BaP-EQs may reduce underestimation in environmental management and risk evaluation regarding PAHs and their derivatives (notably Me-PAHs), suggesting a consideration of using in vitro toxic activity instead of conventional chemical-specific approach in such assessment practices.

Estimation of Crystalline Cellulose Content of Plant Biomass using the Updegraff Method.

Cellulose is the most abundant polymer on Earth generated by photosynthesis and the main load-bearing component of cell walls. The cell wall plays a significant role in plant growth and development by providing strength, rigidity, rate and direction of cell growth, cell shape maintenance, and protection from biotic and abiotic stressors. The cell wall is primarily composed of cellulose, lignin, hemicellulose and pectin. Recently plant cell walls have been targeted for the second-generation biofuel and bioenergy production. Specifically, the cellulose component of the plant cell wall is used for the production of cellulosic ethanol. Estimation of cellulose content of biomass is critical for fundamental and applied cell wall research. The Updegraff method is simple, robust, and the most widely used method for the estimation of crystalline cellulose content of plant biomass. The alcohol insoluble crude cell wall fraction upon treatment with Updegraff reagent eliminates the hemicellulose and lignin fractions. Later, the Updegraff reagent resistant cellulose fraction is subjected to sulfuric acid treatment to hydrolyze the cellulose homopolymer into monomeric glucose units. A regression line is developed using various concentrations of glucose and used to estimate the amount of the glucose released upon cellulose hydrolysis in the experimental samples. Finally, the cellulose content is estimated based on the amount of glucose monomers by colorimetric anthrone assay.

Determination of brominated flame retardants including polybrominated diphenyl ethers, pentabromoethylbenzene, hexabromobiphenyl, and decabromodiphenyl ethane in sediment samples: Validation of a rapid and efficient clean-up method and application to a sediment core from Lake Biwa, Japan

The development of rapid and efficient analytical method for the determination of legacy and current-use brominated flame retardants (BFRs) has been performed due to environmental concern related to these pollutants. In the present study, we used an automated clean-up device equipped with pre-packed micro-column sets (containing sulfuric acid impregnated silica gel and silver-modified alumina) to develop an effective purification method for polybrominated diphenyl ethers (PBDEs), pentabromoethylbenzene, hexabromobiphenyl, and decabromodiphenyl ethane (DBDPE) in sediment extracts. Matrix-spiked sediments (n = 6) and the Standard Reference Material® 1944 samples (n = 6) were tested. Our method showed acceptable accuracy, repeatability, and sensitivity for almost all the target compounds with reduced processing time, labor requirement, and solvent amounts as compared to conventional clean-up method (e.g., sulfuric acid treatment and self-packed chromatographic columns). The validated method was applied to sediment core samples (n = 16) collected in 2019 from Lake Biwa, the largest lake in Japan. PBDEs were detected in sediment samples of 0–13 cm depth (dated between 1990 and 2019) at relatively low concentrations (median 5.7; range 2.6–9.4 ng/g dry weight). PBDE profiles were dominated by BDE-209, which accounted for 91 ± 10% of total PBDEs. Among other BFRs, only DBDPE was found in sediment layers of 0–9 cm depth (deposited between 2005 and 2019). DBDPE concentrations ranged from 0.43 to 1.6 (median 0.71) ng/g and showed increasing trend toward shallower depths.

Production of elastomer-based highly conductive hybrid nanocomposites and treatment with sulfuric acid

Abstract As an elastomer, poly(dimethylsiloxane) (PDMS) is used in various applications such as wearable technology and sealants, and is especially preferred in microelectromechanical device production due to its advantage in fabrication of microstructures. However, some of its applications such as sensor-based or electrode-based are limited due to its insulator aspect. Various conductive nanomaterials such as carbon nanotubes (CNTs), graphene, graphite, carbon black, and silver nanoparticles were incorporated into the PDMS matrix for the production of conductive nanocomposites. In this study, we produced highly conductive PDMS nanocomposites by addition of multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) in a three-dimensional network. Due to the synergistic effect between CNTs and GNPs inside a polymeric matrix, we expected to obtain PDMS nanocomposites more conductive than nanocomposites with only CNTs. Additionally, we investigated the effect of sulfuric acid treatment on the electrical conductivity and surface composition of prepared PDMS/MWCNT/GNP nanocomposites. Results indicated that the electrical conductivity in sulfuric acid-treated samples was significantly higher than in untreated samples. Levels of conductivity in the range of 270.7–1074.8 S/m were achieved; the higher ones were the samples treated with sulfuric acid solution.

Enhanced performance of iron-cerium NOx reduction catalysts by sulfuric acid treatment: The synergistic effect of surface acidity and redox capacity

CeO2-based catalysts have raised extensive attention in selective catalytic reduction of NO with NH3 but the poor T90 operation window limits their industrial application. In present work, FeOx-CeO2 mixed oxides were prepared by a sol-gel method for NH3-SCR, and the effects of sulfuric acid treatment on the catalytic performance were systematically investigated. The results showed that sulfuric acid treatment significantly improved the high temperature activity. Compared to the FeOx-CeO2 sample, the T90 operation window of FeOx-CeO2-S was greatly broadened from 200−300 °C to 250−450 °C. Various characterizations demonstrated that sulfuric acid introduction increased redox capacity and also enhanced surface acidity. The synergistic effect of these two parameters was closely associated with the enhanced performance. Further investigations revealed that the sulfuric acid modification favored the formation of active intermediate species for N2 generation, while inhibited the formation of N2O and NOx, thus contributing to the high catalytic activity and N2 selectivity.

Production of Cellulase and bioethanol by ethanol-tolerant coculture of Bacillus cereus and Fusarium solani

Cellulase is an enzyme produced by fungi and bacteria that hydrolyzes cellulose by breaking down the glycosidic bond, β-1,4 that binds sugar glucose units. Bioethanol and cellulase enzyme were produced by ethanol-tolerant of Bacillus cereus co-culture. So the production of filamentous solani were using the wastes of Cynodon dactylon L. The highest activity of enzyme was at 96 hour/30°C of incubation. The optimal pH value was 7.5, while the carbon concentration was 3%. On the other hand, the best inoculum ratio was 0.5/100 mL (52 × 108 cell/mL bacterial cells and 105 conidia/mL of the fungus). In order to test the efficiency of ethanol production by the co-culture by using different concentrations of pure ethanol was measured in the solid medium. Both Bacillus sp. and F. solani tolerated incubation with 5% ethanol. The best treatment when using 0.5% sulfuric acid which gave the best concentration of reduced sugars and the results showed a difference in the concentration of sugars produced by the fermentation process, it was 3.9 mg/mL in the first day, whereas it was 2.51 mg/mL after 120 hours of fermentation, the concentration of bioethanol produced after fermentation was 195 g/L. In conclusion Cynodon dactylon L. wastes were treated by sulfuric acid, cellulase digestion, and autoclave treatment to be a good source of reducing sugars.

Overcoming the limitations of anthracene alkylation using SZ-DeAl-DFNS acid catalyst

In situ formation of composite micro-mesoporous dendritic fibrous nano-silica (DFNS) and Al-DFNS was prepared using a cetylpyridinium bromide (CPB) template synthetic system. Dealumination is induced by impregnation of zirconium with flux followed by a sulfuric acid treatment. This procedure results in a series of highly uniform nano-spheres, which exhibit stronger acid property than that of Al-MCM-41. In the selective alkylation of anthracene with tert‑amyl alcohol, SO42− modified Zr-contained dealuminated Al-DFNS (SZ-DeAl-DFNS) shows great catalytic activity and higher conversion (60.8%). The DFNS samples were characterized with XRD, SEM, TEM, NH3-TPD and other techniques. The results reveal that DFNSs consist of center-radial micro-mesopores and that the acid contribution of SZ-DeAl-DFNS is much broader, as compared with amorphous aluminosilicate

A biorefinery concept for the production of fuel ethanol, probiotic yeast, and whey protein from a by-product of the cheese industry.

Agroindustrial by-products and residues can be transformed into valuable compounds in biorefineries. Here, we present a new concept: production of fuel ethanol, whey protein, and probiotic yeast from cheese whey. An initial screening under industrially relevant conditions, involving thirty Kluyveromyces marxianus strains, was carried out using spot assays to evaluate their capacity to grow on cheese whey or on whey permeate (100 g lactose/L), under aerobic or anaerobic conditions, in the absence or presence of 5% ethanol, at pH 5.8 or pH 2.5. The four best growing K. marxianus strains were selected and further evaluated in a miniaturized industrial fermentation process using reconstituted whey permeate (100 g lactose/L) with cell recycling (involving sulfuric acid treatment). After five consecutive fermentation cycles, the ethanol yield on sugar reached 90% of the theoretical maximum in the best cases, with 90% cell viability. Cells harvested at this point displayed probiotic properties such as the capacity to survive the passage through the gastrointestinal tract and capacity to modulate the innate immune response of intestinal epithelium, both in vitro. Furthermore, the CIDCA 9121 strain was able to protect against histopathological damage in an animal model of acute colitis. Our findings demonstrate that K. marxianus CIDCA 9121 is capable of efficiently fermenting the lactose present in whey permeate to ethanol and that the remaining yeast biomass has probiotic properties, enabling an integrated process for the obtainment of whey protein (WP), fuel ethanol, and probiotics from cheese whey.Key points• K. marxianus-selected strains ferment whey permeate with 90% ethanol yield.• Industrial fermentation conditions do not affect selected yeast probiotic capacity.• Whey permeate, fuel ethanol, and probiotic biomass can be obtained in a biorefinery.

Multiscale fibril structure of hollow windmill palm fibers

Windmill palm fiber is a kind of multicellular lignocellulose fiber material. Multiscale structure is an essential factor in mechanical properties and applications. The multiscale fibrils under sulfuric acid treatment had been prepared to improve the understanding of the macro-, micro-, and nanoscale structure of the windmill palm fiber. Scanning electron microscopy, atomic force microscopy, wide-angle X-ray scattering, and X-ray diffraction were used to analyze these samples’ structure. Furthermore, the result showed that the elementary fibril diameter was 4–10 nm, whereas that of the microfibrils was 20–70 nm. The diameters of macrofibril and macrofibril bundles were 0.4–1.0 µm and 1.2–5.5 µm, respectively. The elementary fibril assembled into spiral microfibril with an angle of 46°. The crystallinity of nanofibril extracted from windmill palm fiber was about 62%.

Sulfur Promotion in Au/C Catalyzed Acetylene Hydrochlorination.

The formation of highly active and stable acetylene hydrochlorination catalysts is of great industrial importance. The successful replacement of the highly toxic mercuric chloride catalyst with gold has led to a flurry of research in this area. One key aspect, which led to the commercialization of the gold catalyst is the use of thiosulphate as a stabilizing ligand. This study investigates the use of a range of sulfur containing compounds as promoters for production of highly active Au/C catalysts. Promotion is observed across a range of metal sulfates, non-metal sulfates, and sulfuric acid treatments. This observed enhancement can be optimized by careful consideration of either pre- or post-treatments, concentration of dopants used, and modification of washing steps. Pre-treatment of the carbon support with sulfuric acid (0.76 m) resulted in the most active Au/C in this series with an acetylene conversion of ≈70% at 200°C.

Enhanced Hydrophobicity of Nanofibrillated Cellulose Through Surface Modification Using Cetyltrimethylammonium Chloride Derived from Palmityl Alcohol

This study aims to provide an approach for increasing the hydrophobicity of nanofibrillated cellulose in oil palm empty fruit bunches (NFC-OPEFBs) through surface modification using a sustainable cationic surfactant, i.e., cetyltrimethylammonium chloride derived from palmityl alcohol (CTAC-PA). The NFC-OPEFB was prepared by sulfuric acid treatment. The hydrophobicity of NFC-OPEFB was increased following modification using CTAC-PA, indicated by an increase in the water contact angle value. The dispersibility of the modified NFC-OPEFB (modNFC) in chloroform solution was more stable than that of unmodified NFC-OPEFB (unmodNFC) as observed via ultraviolet–visible spectrophotometry and based on visual appearance. Observation through transmission electron microscopy confirmed that modNFC was completely dispersed in chloroform but undispersed in water. Furthermore, Fourier-transform infrared (FTIR) spectroscopy analysis revealed that the functional groups of NFC-OPEFB were successfully modified using CTAC-PA, justifying the increase in their hydrophobicity characteristics. Peaks were observed at 2892 and 2921 cm−1 for symmetrical and asymmetrical CH2 from the long alkyl chain of CTAC, at 1480 cm−1 for the trimethyl groups of the quaternary ammonium, and at approximately 805 cm−1 for the C–Cl bond on the FTIR spectra of modNFC which were absent from the FTIR spectra of the unmodNFC. This work provides an eco-friendly way to enhance the hydrophobicity characteristics of NFC-OPEFB and expand the use of NFC-OPEFB in hydrophobic polymer matrices, such as poly (lactic acid), polyethylene, etc.

Potato peel waste-derived carbon-based solid acid for the esterification of oleic acid to biodiesel

Bio-waste valorization to generate carbon-based solid acid catalysts for biodiesel production from the low-grade, highly acidic feedstocks has been a research hot spot over the last decade. In this study, an abundant bio-waste from the household kitchens, restaurants, and food processing industries, potato peel (PP), was adopted as a raw material for the production of a solid acid catalyst (SO 3 H-PPAC). Firstly, PP was mixed with ZnCl 2 and activated at 450 °C for 1 h to obtain a porous carbon material (PPAC), which was subsequently sulfonated via concentrated sulfuric acid treatment. Various physicochemical techniques, such as XRD, N 2 physisorption measurements, FTIR spectroscopy, and high-resolution transmission electron microscopy (HR-TEM), were used to study the structural properties of the prepared materials. The catalytic behavior of the catalyst was tested in the acid-catalyzed esterification of oleic acid with methanol for biodiesel production. The combination of the high surface area of 827.7 m 2 / g and high concentration of acidic active sites of 1.6 mmol/g led to a high oleic acid conversion efficiency of 97.2% at 5 wt.% SO 3 H-PPAC, methanol/oleic acid molar ratio of 12:1 at 80 °C after 2.5 h. Moreover, the kinetic results unveiled that the esterification reaction obeyed the pseudo-first-order kinetic model, with an activation energy of 32.9 kJ/mol. Importantly, SO 3 H-PPAC has satisfying recyclable features and could maintain ∼ 70 % of its initial catalytic performance in the 5 th catalytic run. • Sulfonated carbon catalyst was synthesized from potato peel by ZnCl 2 activation and sulfonation. • The obtained catalyst exhibited high surface area of 827.7 m 2 g -1 . • Synthesized catalyst used in oleic esterification acid and afforded a high conversion of 97.2%. • The catalyst maintained ∼ 70 % of its initial catalytic performance in the 5 th catalytic run.

Synthesis and Characterization of Pine-cone Derived Carbon-based Solid Acid: a Green and Recoverable Catalyst for the Synthesis of Pyrano_ pyrazole, Amino-benzochromene, Amidoalkyl Naphthol and Thiazolidinedione Derivatives

In this report, SO<sub>3</sub>H-functionalized Carbon nanoparticles (Pine-SO<sub>3</sub>H) with high acid density have been synthesized by the thermal treatment of sulfuric acid with Pine-Cone as carbon-based at 180°C in a sealed autoclave in a one-step procedure. The resulted Nanocatalyst was characterized by FT-IR, TGA, XRD, FE-SEM and elemental analysis (EA). The result of characterization was shown that the carbon-based acid is amorphous with polycyclic aromatic carbon sheets attached plentiful -OH, -COOH, and -SO<sub>3</sub>H groups. The catalytic activities of Pine-SO<sub>3</sub>H was investigated in the highly efficient synthesis of pyrano[2,3-c] pyrazole, amino-benzochromenes, amidoalkyl naphthol and 5-arylidene-2,4-thiazolidinedione derivatives. The application of Pine-SO<sub>3</sub>H in the synthesis offers several advantages such as simple procedure with an easy work-up, recoverable catalyst, mild condition, eco-friendliness, excellent yields, short reaction times and use of an inexpensive catalyst.

Sulfuric Acid Treated g-CN as a Precursor to Generate High-Efficient g-CN for Hydrogen Evolution from Water under Visible Light Irradiation

Modifying the physical, chemical structures of graphitic carbon nitride (g-CN) to improve its optoelectronic properties is the most efficient way to meet a high photoactivity for clean and sustainable energy production. Herein, a higher monomeric precursor for synthesizing improved micro-and electronic structure possessing g-CN was prepared by high-concentrated sulfuric acid (SA) treatment of bulk type g-CN (BCN). Several structural analyses show that after the SA treatment of BCN, the polymeric melon-based structure is torn down to cyameluric or cyanuric acid-based material. After re-polycondensation of this material as a precursor, the resulting g-CN has more condensed microstructure, carbon and oxygen contents than BCN, indicating that C, O co-doping by corrosive acid of SA. This g-CN shows a much better visible light absorption and diminished radiative charge recombination by the charge localization effect induced by heteroatoms. As a result, this condensed C, O co-doped g-CN shows the enhanced photocatalytic hydrogen evolution rate of 4.57 µmol/h from water under the visible light (>420 nm) by almost two times higher than that of BCN (2.37 µmol/h). This study highlights the enhanced photocatalytic water splitting performance as well as the provision of the higher monomeric precursor for improved g-CN.

Effect of Acid Treatment on Electrocatalytic Performance of PtNi Catalyst

In this paper, we describe the synthesis of the AC-PtNi/G catalysts with graphene as the carrier, via the alcohol reduction and the sulfuric acid treatment. The prepared catalysts were microscopically characterized by X-ray diffractometry(XRD), X-ray photoelectron spectroscopy(XPS), scanning electron microscopy(SEM), electron spectroscopy(EDAX), and transmission electron micros-copy(TEM). We tested the electrochemical performance of the prepared catalysts using an electrochemical workstation and in situ infrared spectroscopy(FTIR). The results showed that the acid-treated AC-PtNi/G catalysts had a more uniform dispersion and with the increased of treatment time, the particle size of the catalyst became smaller. And the electrocatalytic performance of the AC-PtNi/G-48h catalyst treated with sulfuric acid for 48 h was significantly better than that of the untreated PtNi/G catalyst. Its electrochemically active surface area was 76.63 m2/g, and the peak current density value for catalytic oxidation of ethanol was 1218.83 A/g, which was 10 times that of ordinary commercial Pt/C catalyst. The steady-state current density value of 1100 s was 358.77 A/g, and it has excellent anti-CO toxicity performance. It was determined that a sulfuric acid treatment controlled catalyst particle size and increased the electrocatalytic activity of the catalytic oxidation of ethanol.

Extraction of impurities from phosphorite ore in concentration and processing

The article presents a review of the reports on the composition and properties of phosphorite ore from the Polpino deposit and on the problems connected with the ore processing by dry fractional crushing–sifting separation. The content of impurities in this ore exceeds the standard, which eliminates technological capability of straight sulfuric acid treatment of the ore for wet-process phosphoric acid production. The attempted wet processing of the ore by solutions of weak organic acids, selected because of their availability, regenerative capacity and environmental safety, is described. It is found that the organic acids are lo w-effective in extraction of alkaline-earth metal impurities: extraction is not higher than 3.5 and 9.5 % with acetic and formic acids, respectively; total recovery of Al2O3 and Fe2O3 is not higher than 2.0 and 8.0 %, and is factually independent of concentration of the acids. The authors prove straight processability of phosphorite ore by sulfuric acid treatment with production of compound fertilizers, including selective removal of impurities and carbonate minerals, and controlled recovery of iron and aluminium. The optimization parameters of the process are concentration of nitric acid, the acid–ore interaction time and temperature. These parameters should ensure complete extraction of the target component to solution (99.0 %), as well as controlled removal of iron impurities (18.0–20.0 %) and aluminium impurities (31–32 %), which have an adverse influence on rheological properties of suspensions. Thus, the article proves technological capability of straight processing of Polpino phosphorite resources containing Р2О5–15.3 %, CaO–27.42 %, MgO–0.95 %, Fe2O3–2.58 % and Al2O3–3.65 % without pretreatment.

Hydolysis of multi substrate biomass using para-toluenesulphonic acid for bioethanol production: A promising option over the sulfuric acid treatment

The municipal and agricultural wastes are promising source of ligniocellulosic biomasses (LBs) for bioethanol production. However, the pretreatment-hydrolysis (P–H) of LB is the most difficult process in bioethanol production due to high crystallinity of LB compositional structures. In this study, p-toluenesulphonic acid (PTSA) was investigated for P–H of multi-substrate (MS) sample of LBs. Five alternative MS samples were prepared from 10 single LBs. Based on the total reducing sugar yield, one of the MS was selected for optimization experiment. The factors affecting P–H (acid concentration, time and temperature) were optimized to compare catalytic activity of PTSA and H2SO4. Under the optimized conditions, maximum total reducing sugar (TRS) yield of 95.89 and 78.26% was obtained using PTSA and H2SO4, respectively. Mass production of hydrolysate was carried out using both catalysts at a substrate load of 50 g.L−1 and fermented at an optimum yeast load of 10% (v/v). The ethanol yield from the hydrolysates of PTSA treatment was 16.89 g L−1 (74.5%) and from H2SO4 was 13.17 g L−1 (70.9%) at 48 & 56 h fermentation time, respectively. The PTSA surpassed the conventional method of treatment (H2SO4) both in TRS and ethanol yield. The efficiency of PTSA can be noticed in that one third of the acid concentration required in sulfuric acid treatment was used in PTSA to obtain 96% of TRS at lower temperature. This study revealed the potential of aqueous PTSA for the hydrolysis of a mixture of feedstocks which is much more complex and challenging than treating a single substrate.

Eucheuma cottonii Seaweed-Based Biochar for Adsorption of Methylene Blue Dye

Pollution from dye containing wastewater leads to a variety of environmental problems, which can destroy plant life and eco-systems. This study reports development of a seaweed-based biochar as an adsorbent material for efficient adsorption of methylene blue (MB) dye from synthetic wastewater. The Eucheuma cottonii seaweed biochar was developed through pyrolysis using a tube furnace with N2 gas, and the properties were later improved by sulfuric acid treatment. The adsorption studies were conducted in a batch experimental setup under initial methylene blue concentrations of 50 to 200 mg/L, solution pH of 2 to 10, and temperature of 25 to 75 °C. The characterization results show that the developed biochar had a mesoporous pore morphology. The adsorbent possessed the surface area, pore size, and pore volume of 640 m2/g, 2.32 nm, and 0.54 cm3/g, respectively. An adsorption test for 200 mg/L of initial methylene blue at pH 4 showed the best performance. The adsorption data of the seaweed-based biochar followed the Langmuir isotherm adsorption model and the pseudo-second-order kinetic model, with the corresponding R2 of 0.994 and 0.995. The maximum adsorption capacity of methylene blue using the developed seaweed‑based biochar was 133.33 mg/g. The adsorption followed the chemisorption mechanism, which occurred via the formation of a monolayer of methylene blue dye on the seaweed-based biochar surface. The adsorption performance of the produced seaweed biochar is comparable to that of other commercial adsorbents, suggesting its potential for large-scale applications.

Tear resistant Tyvek/Ag/poly(3,4-ethylenedioxythiophene): Polystyrene sulfonate (PEDOT:PSS)/carbon nanotubes electrodes for flexible high-performance supercapacitors

• Tyvek paper substrate applied in the supercapacitors for the first time. • High flexibility and excellent tear resistance of the supercapacitors. • Higher power density and energy density compared with CNTs-related and PEDOT:PSS-based supercapacitors. The current information era has witnessed the fast development of flexible high-performance energy storage devices for portable and wearable smart electronics. Here, tough supercapacitor with high flexibility and tear resistance based on Ag-coated Tyvek/PEDOT:PSS/carbon nanotubes (Tyvek/Ag/PCNTs) composite electrodes has been well designed and fabricated for the first time via a facile and scalable method. In the supercapacitor, Ag-coated Tyvek substrate roles as the current collector through a polymer-assisted metal deposition method while the treatment of sulfuric acid on the electrode contributes to the removal of insulating PSS part and the increase of the crystallinity of the active materials. Due to the tough and flexible substrate and the increased conductivity of the electrodes, the supercapacitor exhibits excellent stability and rate capacity as well as brilliant mechanical strength and flexibility. The prepared supercapacitor can exhibit large specific mass capacitance (138.7 F/g) and specific volume capacitance (544.2 F/cm 3 ) at the scan rate of 50 mV/s. As far as we can concern, the Tyvek/Ag/PCNTs-based supercapacitor owns higher energy density or power density than any other CNTs-based or PEDOT-related supercapacitors. In addition, after 1000 bending cycles, the capacitance of the supercapacitor can still reach to 91.2% of the initial value. This work will help to enlarge the study in the Tyvek-based supercapacitors for the flexible and tough energy storage devices.

Dilute acid pretreatment and enzymatic sachharification of cotton ginning waste

Background/Objective: The objective is to study the effect of dilute sulfuric acid pretreatment and enzymatic saccharification of cotton ginning waste to produced fermentable sugars. The Box Behnken design (BBD) was used for optimization of physical parameters. Method: Cellulase production by Trichoderma sp. (A11) was carried out under solid state fermentation using wheat bran. Pretreatment were carried out with 3% (V/V) diluted sulfuric acid and sachharification with crude cellulase enzyme of cotton ginning waste. The proximate analysis of treated and untreated cotton ginning biomass was done by Goering and Van Soest method to find the cellulose, hemicellulose and lignin content. The total reducing sugar was measured by using Di-nitro salicylic acid (DNSA) method. Incubation time, moisture ratio and substrate loading was optimized by using BBD for sachharification of cotton ginning waste. Finding: Untreated cotton ginning waste biomass contain 40.7% (w/w) of cellulose and 17.3 % (w/w) of lignin. Under sulfuric acid treatment, the residual acid treated cotton ginning waste biomass was found to have 62.4  4.1 % (w/w) cellulose and 9.9  0.6 % (w/w) lignin. Acid treated cotton ginning waste produced 117.3 mg/g while as untreated cotton ginning waste produced 29.7mg/g total reducing sugar. After statistical optimization by using BBD total reducing sugar was increased to 328 mg/g experimentally, at an optimum 5% of substrate concentration, 10 FPU enzyme loading on 7th day of incubation period and at 5 pH. Application: The fermentable sugar which is produced from cotton ginning waste biomass which can be further utilized for bioethanol production. Keywords: Cotton ginning waste; acid pretreatment; Cellulase; enzymatic sachharification