Sherif A. Younis

Construction of a new ternary α-MoO3–WO3/CdS solar nanophotocatalyst towards clean water and hydrogen production from artificial wastewater using optimal design methodology

Photocatalytic wastewater remediation and hydrogen generation were successfully achieved using a novel α-MoO3(0.03)–WO3(0.36)/CdS(0.61) heterojunction photocatalyst, fabricated by a solid-state approach. Through statistical optimal design of experiments (ODOE), simplex centroid design (SCD) and Box–Behnken design (BBD) were used to optimize the preparation and photocatalytic processes. The effects of combinatorial catalyst ratios on the photocatalytic responses were modeled using SCD under ultraviolet and visible light factors. Using BBD, the photodegradation experiments were fitted to the quadratic polynomial relationship with significance terms in the order of pH > catalyst dose > pollutants concentrations. The apparent first-order rate constants (Kapp) of the developed ternary photocatalyst revealed that the solar-driven photoreaction is 1.4 times higher than the visible activation. The photocatalytic activities reached a maximum of 75% removal of total organic contaminants (TOC) and hydrogen yield of 8 μmol g−1 h−1 after 6 h of solar-harvesting with good photostability and durability for 5 cycles. The notable oxidation–reduction photoreaction of the ternary photocatalyst is attributed to the constructed Z-scheme by the synergic CdS–WO3–α-MoO3 heterojunction interaction. This work proves the power of ODOE to manufacture a photostable α-MoO3(0.03)–WO3(0.36)/CdS(0.61) solar-photocatalyst for a green environment.

Utilization of a pyrrole derivative based antimicrobial functionality impregnated onto CaO/g-C3N4 for dyes adsorption

A novel functionalization of CaO/g-C3N4 based nanocomposite using 4,5-diphenyl-2-thioxo-2,5-dihydro-1H-pyrrole-3-cabonitrile (P3C@CaO–HCN) was performed for wastewater remediation from organic dyes and microbial pollutants. Adsorption performance of multiple mixtures of basic and acidic dyes by P3C@CaO–HCN was investigated and optimized using a three-level Box–Behnken design of experiment (BBD-DOE). The quadratic Box–Behnken polynomial equation showed the best fit with experimental adsorption capacities of crystal violet (CV), methylene blue (MB), and methyl orange (MO) model dyes. The simultaneous influence of adsorption conditions was tested based on the developed Box–Behnken equation, 3D contour plots, and ANOVA analysis. Nonlinear regression analysis of kinetics and isotherm constants were computed and validated to propose the adsorption mechanism. Adsorption was found within the ranges of endothermic physical adsorption (ΔH° = 6.17 to 8.58 kJ mol−1) and controlled by both π–π and electrostatic forces depending on the pH level in addition to film diffusion mechanism. The maximum adsorption affinity can be arranged in the order of MB > CV ≥ MO with qe (µmol g−1) of 1915.8, 1227.8, and 1221 µmol g−1, respectively. At 500 mg L−1 P3C@CaO–HCN as the minimum inhibitory dose, the inhibition rates (I%) were 87.9%, 46.9%, and 72.5% for E. coli, P. aeruginosa, and C. albicans, respectively. The antimicrobial effect can result from the free cyanide (CN) functionality of a pyrrole-3-cabonitrile and protonated g-C3N4 (HCN) sheet, which depends on the P3C@CaO–HCN concentration and pathogen types.

Kinetic evaluation and modeling for batch degradation of 2-hydroxybiphenyl and 2,2′-dihydroxybiphenyl by Corynebacterium variabilis Sh42

abstract This study evaluated the biodegradation kinetics of 2-hydroxybiphenyl (2-HBP) and 2,2′-dihydroxybiphenyl (2,2′-DHBP) with different initial concentrations range S 0 (5–50 mg/L) using suspended cultures of Corynebacterium variabilis Sh42 with fixed initial biomass concentration X 0 (315.8 mg/L) in a series of batch experiments. The cultures followed substrate inhibition kinetics. By fitting specific growth rates μ (h−1) on suitable substrate inhibition models, biokinetic constants that are necessary to understand the kinetics of biodegradation process were evaluated by POLYMATH 6.1 software. Although Haldane and Yano and Koga (2) biokinetic equations for substrate inhibition seem to be the best adequate expressions for specific growth rates on 2-HBP and 2,2′-DHBP, respectively, an evident disagreement was observed between experimental and simulated profiles for bacterial growth X (mg/L) and substrate concentration S (mg/L). Correlation and simulation studies using a new proposed model based on mod...

Application of Response Surface Methodology to Enhance Phenol Removal from Refinery Wastewater by Microwave Process

Phenol contaminated petroleum refinery wastewater presents a great threat on water resources safety. This study investigates the effect of microwave irradiation on removal of different concentrations of phenol in an attempt for petroleum refinery wastewater treatment. The obtained results show that the MW output power and irradiation time have a significant positive effect on the removal efficiency of phenol. The kinetic reaction is significantly affected by initial MW output power and initial phenol concentrations. Response surface methodology (RSM) was employed to optimize and study the interaction effects of process parameters: MW output power, irradiation time, salinity, pH, and H2O2 concentration using central composite design (CCD). From the CCD design matrix, a quadratic model was considered as an ultimate model (2 = 0.75) and its adequacy was justified through analysis of variance (ANOVA). The overall reaction rates were significantly enhanced in the combined MW/H2O2 system as proved by RSM. The optimum values for the design parameters of the MW/H2O2 process were evaluated giving predicted phenol removal percentage of 72.90% through RSM by differential approximation and were confirmed by experimental phenol removal of 75.70% in a batch experiment at optimum conditions of 439 W MW power, irradiation time of 24.22 min, salinity of 574 mg/L, pH 5.10, and initial H2O2 concentration of 10% (v/v).

Optimization of a batch CaO-catalyzed transesterification of used domestic waste oil with methanol and elucidation of a mathematical correlation between biodiesel yield and percent conversion

ABSTRACT The major drawback of the wide applicability of biodiesel is its price compared to the conventional petro-diesel. The feedstock and the applied catalyst in the transesterification reaction are the main contributor for the overall cost of the biodiesel production. Thus, this study summarizes the optimization of a batch transesterification reaction of used domestic waste oil (UDWO) with methanol using CaO, which can be easily prepared from different cheap and readily available natural sources. Quadratic model equations were elucidated describing the effect of methanol:oil molar ratio, CaO concentration wt.%, reaction temperature °C, reaction time h, and mixing rate rpm on biodiesel yield and conversion percentage. The optimum operating conditions were found to be competitive with those of the high-cost immobilized enzyme Novozym435. An overall acceptable agreement was achieved between the produced biodiesel, its blends with petro-diesel and the available commercial petro-diesel, and the international fuel standards. A precise and reliable logarithmic mathematical model was predicted correlating the production of pure high-quality biodiesel yield with the conversion percentage which were measured based on the fatty acid methylester content and decrease in viscosity, respectively.

Main and Interactive Effects of Polyaromatic Sulfur Heterocyclic Compounds on Growth and Biodegradation Efficiencies of Bacillus sphaericus HN1: Modeling and Statistical Analysis

Bioremediation is an effective technique to remediate soil and water contaminated with a mixture of recalcitrant polyaromatic sulfur heterocyclic (PASH) compounds. Based on two levels of full factorial design, a statistical design of experiments was used in this study to investigate the interactive effects of three PASHs; thiophene (Th), benzothiophene (BT), and dibenzothiophene (DBT) on their biodegradation in multisubstrate batch process using Bacillus sphaericus HN1. Kinetic modeling was performed to estimate the rate of biodegradation of each PASH in single-, binary-, and tertiary-substrate systems. Biodegradation of BT, DBT, and total PASHs follows the first order kinetic reaction in the single- and multisubstrate batch systems, while biodegradation of Th follows the first-order kinetic reaction, in single-substrate system, but second-order kinetic reaction in multisubstrate batch system. Four linear interaction regression models were estimated and validated to describe the interactive effect of the three PASHs on their biodegradation. Statistical analysis of the results in the form of analysis of variance and Student t test indicated significant role played by the main effects of Th, BT and DBT on their biodegradation (p < 0.01). Th and the interactive effect between Th and DBT has statistically significant negative effect on DBT removal (p = 0.0665). However, DBT expresses higher statistically significant positive effect on total PASHs removal than that of Th (p = 0.0178 and p = 0.026, respectively), but their interaction has a significantly negative effect (p = 0.0143).

The Utilization of Activated Carbon/Lignin Biocomposite as Recyclable Sorbent For In-Situ Removal of High-Concentration BTX from Petroleum Wastewater

Extended Abstract Among varies petroleum pollutants of interest, BTX (i.e., benzene, toluene, and xylene of ortho, meta and para-positions) mono-aromatics has found to be the most environmental problem [1]. Environmental legalization policies are listed BTX as contaminants of emerging concerns (CECs) because of their potential toxic and/or carcinogenic properties for human health or animals and drinking water contamination, even in trace levels [2]. In this work, a facile one-pot co-precipitation process was developed to construct granule activated carbon (gAC)/Kraft lignin (KL) biocomposite (gAC/KLx) as a new eco-friendly sorbent from recycling industrial wastes of both palm-date pits and pulping black liquor. The synthesized gAC/KLx biocomposite with defined characteristics using ATR-FTIR, XRD, SEM, BET, TGA, DLS and Zeta potential analyses was utilized as an effective sorbent of environmentally toxic BTX compounds (benzene, toluene and xylene) from petroleum wastewater effluents. Sorption behavior of BTX over gAC/KLx biocomposites with different ratios of Kraft lignin (x = 33, 50 and 67%) in batch experiments were evaluated using high performance liquid chromatography (HPLC). Interestingly, the gAC/KL showed the highest sorption capacity of BTX at lignin blended ratio of 50%, even from broad ranges of water salinity (up to 100,000 mg/L) and pH values (pH 4 9). The sorption behavior of BTX compounds were found to fit better to a type two pseudo-second kinetic (adsorption kinetic rate of BTX at 0.104 g.mg.min) and Langmuir isotherm models, as confirmed by the higher coefficient of R> 0.98. The sorption affinities of the gAC/KL0.5 biocomposite with respect to 250 mg/L BTX can be ordered in the sequence Xylene > Toluene ≥ benzene with highest monolayer capacities reached to 170.5, 160.5 and 159.7 mg/g, respectively after 6 h. The adsorption mechanism was found to follows the diffusion and hydrophobic sorption mechanisms. Particularly, the possibilities of BTX elution for gAC/KL0.5 reuse were evaluated up to five cycles without high significant loss in sorption efficiencies during multiple wastewater treatment. As such, on the basis of batch BTX sorption studies, the gAC/KL0.5 is expected to be a promising low cost and high performance new sorbent to be reutilize for real wastewater treatment process and petroleum hazardous decontamination with higher thermal stability (up to 350 C) and aqueous stability (10% 21% efficiency loss).

Statistical enhancement of lipase extracellular production by Bacillus stratosphericus PSP8 in a batch submerged fermentation process

The aim of this study was to isolate and identify lipolytic bacteria. Perform a statistical stepwise physicochemical optimization for maximum production of extracellular lipase and its validation in a bioreactor.

Batch bioethanol production via the biological and chemical saccharification of some Egyptian marine macroalgae

Marine seaweeds (macroalgae) cause an eutrophication problem and affects the touristic activities. The success of the production of the third‐generation bioethanol from marine macroalgae depends mainly on the development of an ecofriendly and eco‐feasible pretreatment (i.e. hydrolysis) technique, a highly effective saccharification step and finally an efficient bioethanol fermentation step. Therefore, this study aimed to investigate the potentiality of different marine macroalgal strains, collected from Egyptian coasts, for bioethanol production via different saccharification processes.

Physiochemical properties of Trichoderma longibrachiatumDSMZ 16517-synthesized silver nanoparticles for the mitigation of halotolerant sulphate-reducing bacteria

In order to efficiently control the corrosive sulphate‐reducing bacteria (SRB), the main precursor of the microbial influenced corrosion (MIC) in oil industry, the ability of Trichoderma longibrachiatumDSMZ 16517 to synthesize silver nanoparticles (AgNPs) was investigated and their biocidal activity against halotolerant SRB was tested.