High interfacial charge separation in visible-light active Z- scheme g-C3N4/MoS2 heterojunction: Mechanism and degradation of sulfasalazine

Examination of highly proficient photoactive materials for the degradation of antibiotics from the aqueous solution is the need of the hour. In the present study, a 2D/2D binary junction GCM, formed between graphitic-carbon nitride (g-C3N4) and molybdenum disulphide (MoS2), was fabricated using facile hydrothermal method and its photo-efficacy was tested for the degradation of sulfasalazine (SUL) from aqueous solution under visible-light irradiation. Morphological analysis indicated the nanosheets arrangement of MoS2 and g-C3N4. The visible-light driven experiments indicated that 97% antibiotic was degraded by GCM-30% within 90 min which was found to be quite high than pristine g-C3N4 and MoS2 at solution pH of 6, GCM-30% dose of 20 mg, and SUL concentration of 20 mgL-1. The degradation performance of GCM-30% was selectively improved due to enhanced visible-light absorption, high charge carrier separation, and high redox ability of the photogenerated charges which was induced by the effective Z-scheme 2D/2D heterojunction formed between g-C3N4 and MoS2. The reactive radicals as determined by the scavenging study were •O2-, and h+. A detailed degradation mechanism of SUL by GCM-30% was also predicted based on the detailed examination of the band gaps of g-C3N4 and MoS2

Challenges and perspectives on innovative technologies for biofuel production and sustainable environmental management

Specifically, human activities, such as those in industry and transportation, have resulted in an increase in the demand for fossil fuels, resulting in severe environmental problems.Throughout this article, we discuss the potential and challenges associated with the production of biofuels from a variety of feedstocks and advances in processing technologies utilizing a range of feedstocks. Based on the conclusion of the study, we conclude that bioenergy is a green alternative to be used for diverse energy needs, once the appropriate conversion processes are applied. The production of biofuels and their use in industries and transportation have significantly reduced the use of fossil fuels. The literature review concluded that producing biofuels from energy crops and microalgae was the most efficient and attractive method. The purpose of this review is to explain all aspects of biofuels and their sustainability criteria. With a particular focus on the role of nanotechnology in biofuel production, this article discusses the most recent advances in biofuel production. A number of emerging techniques have been investigated for improving process quality, including integrated techniques, less energy-intensive distillation strategies, and the use of microorganisms in engineering. A challenging aspect of biofuel production on a large scale remains; therefore, a novel technology must be developed in order to enhance biofuel production in order to meet the challenges and meet future energy needs

Removal of nutrients from pulp and paper biorefinery effluent : operation, kinetic modelling and optimization by response surface methodology

This study investigated the effectiveness of extended aeration system (EAS) and rice straw activated carbon-extended aeration system (RAC-EAS) in the treatment of pulp and paper biorefinery effluent (PPBE). RAC-EAS focused on the efficient utilization of lignocellulosic biomass waste (rice straw) as a biosorbent in the treatment process. The experiment was designed by response surface methodology (RSM) and conducted using a bioreactor that operated at 1–3 days hydraulic retention times (HRT) with PPBE concentrations at 20, 60 and 100%. The bioreactor was fed with real PPBE having initial ammonia-N and total phosphorus (TP) concentrations that varied between 11.74 and 59.02 mg/L and 31–161 mg/L, respectively. Findings from the optimized approach by RSM indicated 84.51% and 91.71% ammonia-N and 77.62% and 84.64% total phosphorus reduction in concentration for EAS and RAC-EAS, respectively, with high nitrification rate observed in both bioreactors. Kinetic model optimization indicated that modified stover models was the best suited and were statistically significant (R 2 ≥ 0.98) in the analysis of substrate removal rates for ammonia-N and total phosphorus. Maximum nutrients elimination was attained at 60% PPBE and 48 h HRT. Therefore, the model can be utilized in the design and optimization of EAS and RAC-EAS systems and consequently in the prediction of bioreactor behavior

Production and harvesting of microalgae and an efficient operational approach to biofuel production for a sustainable environment

Biofuel derived from microalgae has developed as an environmentally benign alternative to conventional fossil fuels. Mass production of this biofuel remains difficult due to several of technological and economic issues ranging from commercial production and harvesting of microalgae to biofuel production. The major impediments to establishing an integrated system are large-scale microalgal production and harvesting in a manner that allows for downstream processing to produce biofuels and other useful bioproducts. We integrated and evaluated suspended cultures in open ponds and closed reactors for algal production systems, emphasizing the advantages of attached cultures for algal production. The challenge of harvesting microalgae in liquid growing media has been addressed by technical improvements that have incorporated chemical, mechanical, biological and thermal approaches for dewatering microalgal suspensions and extracting additional bioproducts. Nonbiological approaches such as centrifugation, electrocoagulation, chemical, electrical, and magnetic nanoparticle flocculation, filtering, and biological coculture-based methods were evaluated for their feasibility and considerations in establishing microalgae harvesting systems. The latest breakthroughs in bacteria and fungi-based coculture algae-flocculation technology are discussed. Additionally, this review considers the opportunities for genetic engineering innovation and resources for increasing microalgae production and harvesting, as well as for developing new bioproducts in a sustainable and cost-effective manner

Hole-induced polymerized interfacial film of polythiophene as co-sensitizer and back-electron injection barrier layer in dye-sensitized TiO2 nanotube array

In this work, we demonstrate that an ultra-thin film of polythiophene deposited interfacially via hole-induced polymerization on the surface of dye-sensitized TiO2 nanotube array acts as co-sensitizer, and hinders back-electron transfer in a DSSC. Consequently, the dark current, and the recombination reactions can be suppressed, leading to an improved number of electron density at the TiO2 array electrode. Thus, an enhanced photocurrent, and power conversion efficiency of the device is achieved. This logical concept is experimentally justified, and the device, after polythiophene interfacial treatment, demonstrates an enhanced power conversion efficiency by the factor of 39.19%. (C) 2018 Elsevier B.V. All rights reserved.11Nsciescopu

Facile synthesis and optoelectronic exploration of silylthiophene substituted benzodithiophene polymer for organic field effect transistors

This work reports the synthesis, characterization and organic field effect transistors (OFET) application of a novel conjugated polymer (PBDTDPP) based on silylthiophene substituted benzo[1,2-b:4,5-b']dithiophene (BDT) donor and diketopyrrolopyrrole (DPP) acceptor obtained via Stille polymerization reaction. The polymer exhibits a broad absorption in the UV-visible spectrum ranging from 300 nm to 900 nm with the band edge of the polymer at 1.31 eV. Thermogravimetric analysis of the polymer demonstrates the stability up to 303 degrees C, and the cyclic voltammetry shows the HOMO and LUMO levels at -5.42 and -4.11 eV, respectively. Employing the polymer as an active layer in a bottom gate-top contact based OFET, hole mobility of as high as 9.34 x 10(-2) cm(2) V-1 s(-1) with the On/Off ratio of similar to 10(4) was obtained. This work successfully demonstrates that the DPP and the silylthiophene substituted BDT are promising units to build D-A based copolymer for organic electronics. (c) 2018 Elsevier B.V. All rights reserved.11Nsciescopu

Acceptor Unit Effects for Ambipolar Organic Field-Effect Transistors Based on TIPS-Benzodithiophene Copolymers

Two narrow band gap triisopropylsilyl substituted benzo[1,2-b:4,5-b] dithiophene (TIPS-BDT) derivatives, P1 (1.65 eV) and P2 (1.46 eV) are synthesized for ambipolar organic field-effect transistors and complementary inverters. Two electron acceptor units, heptadecanyl substituted thieno[3,4-c]pyrrole-4,6-dione (TPD) and ethylhexyl substituted diketopyrrolo[3,4-c]pyrrole (DPP) are incorporated to tune the structure and resulting properties of the donor-acceptor type copolymers. Structural modification based on the acceptor unit variation, resulted in comparable electrochemical, optical, microstructural, and charge transporting properties, as well as environmental and operational stability. TIPS-BDT copolymers with TPD acceptor units show comparatively superior performance, with field effect mobility approximate to 10(-3) cm(2)V(-1)s(-1) for both holes and electrons and inverter gain approximate to 18 with poly(methyl methacrylate) gate dielectric.11Nsciescopuskc

Precipitation of (Mg/Fe-CTAB) - Layered double hydroxide nanoparticles onto sewage sludge for producing novel sorbent to remove Congo red and methylene blue dyes from aqueous environment

Preparation of new sorbent from precipitation of nano-sized (Mg/Fe-CTAB)- layered double hydroxide (LDH) on the surfaces of sewage sludge byproduct to remove the anionic and cationic dyes was the focal point of this work. The presence of nanoparticles and enlarged of interlayers by CTAB intercalation have increased the sludge surface area from 5.34 to 10.32 m2/g. The CTAB mass 0.03 g/50 mL, sludge dosage 1 g/50 mL and (Mg/Fe) molar ratio 2 were the best preparation conditions required to obtain effective sorbent with efficiencies exceeded 93% for MB and CR dyes. These efficiencies were obtained under operational conditions for batch study of 0.5 g coated sludge per 50 mL colored dye solution, initial pH 3 (for CR) and 12 (for MB), and time 3 h for 10 mg/L dyes at 200 rpm. Models of Langmuir and pseudo second-order have a high capability in the representation of sorption records with maximum capacities of adsorption 163.6 and 132.6 mg/g for CR and MB dye, respectively. The X-ray diffraction analysis proved that the calcite occurred mainly at 2θ = 29.8° while quartz corresponded to the 21, 26.6, 36.4, 36.9, 50.1, 60.01 and 68.4°. Characterization tests showed that nano-sized particles of magnesium/iron were precipitated on the sludge due to the formation of hydrotalcite-like compounds with an increase in the percentages of Mg and Fe from 0.87 to 1.36 to 4.25 and 3.03%, respectively. The results showed that the electrostatic attraction, intra-particle diffusion and hydrogen bonding were predominant mechanisms for removal of CR and MB onto coated sludge.Validerad;2022;Nivå 2;2022-02-15 (hanlid);Funder: King Saud University (RSP-2021/8)</p

Au-Pd bimetallic nanoparticles embedded highly porous Fenugreek polysaccharide based micro networks for catalytic applications

Currently, metallic nanoparticles possessing versatile heterogeneous catalytic functionality such as in hydrogenation, water splitting, hydrogen production and CO2 reduction for global pollution remediation have been paid great attentions due to their high chemical stability, superior activity and unique electrical and optical properties. However, the gradual degradation of their catalytic activity on multiple usage limits the monometallic nanoparticles to industrial applications. Herein, we fabricated the highly porous fenugreek polysaccharide assisted green synthesis of Au-Pd nanostructures for heterogeneous catalytic hydrogenation of the industrial usable highly toxic 4-nitrophenol to the medicinally useful 4-aminophenol. The aqueous method developed in the present work is environmentally friendly, simple and low-cost procedure. The fabricated bimetallic porous Au Pd nano structures characterized using SEM, TEM, UV-Vis, XRD, XPS and FTIR analysis. The catalytic activity of the synthesized nanostructures was studied for the heterogeneous hydrogenation of 4-nitrophenol to 4-aminophenol in presence of NaBH4, and the catalytic kinetic for the hydrogenation was analyzed via an UV-Vis spectrometer. (C) 2018 Elsevier B.V. All rights reserved.11Nsciescopu