Biodiesel production from Nannochloropsis is investigated in the current study. Based on the extraction studies, the used biomass is composed of 50% saponifiable lipids, which turns this species to a ...vulnerable feedstock for biodiesel production. It should also be noted that the acidity of the obtained crude bio‐oil is higher than 2 mg KOH/g, hence it was attempted to survey the biodiesel production from the obtained oil through the esterification reaction with the aid of response surface methodology (RSM). According to the data, the highest biodiesel yield (99.5%) from the bio‐oil is obtained at a reaction temperature of 69°C, a reaction time of 30 min, a methanol to oil molar ratio of 9:1, and an H2SO4 concentration of 0.13 wt.%. In the next step, the in‐situ extraction and esterification of Nannochloropsis were investigated at the observed optimum reaction conditions. Based on the analysis, biodiesel yield from the dry cell weight of the biomass is considered to be 16%, which accounts for 99% conversion of bio‐oil to biodiesel.
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The facile synthesis of crosslinked chitosan-tripolyphosphate/kaolin clay (CS-TPP/KC) composite was performed by two subsequent steps involving modification of chitosan (CS) with an ...inorganic clay (kaolin, KC), followed by ionic cross-linking reaction by tripolyphosphat (TPP). The applicability of the CS-TPP/KC composite for decolourization and chemical oxygen demand (COD) reduction of remazol brilliant blue R dye (RBBR) from aquatic system was investigated. The main key factors that influences the RBBR dye decolourization and COD reduction such as A: CS-TPP/KC dosage (0.02−0.1 g), B: pH (4–10), and C: time (5−30 min) were optimized by using Box–Behnken design (BBD). The highest RBBR dye decolourization (99.5 %) and COD reduction (88.5 %) were observed at the following significant interactions: AB, BC, and AC (only on COD reduction was significant). Langmuir isotherm was the best model presented the adsorption process with remarkable adsorption capacity of 687.2 mg/g was obtained for CS-TPP/KC composite at 30°C. This work highlights that CS-TPP/KC composite offers great potential as a low-cost and effective biocomposite material for the organic dyes removal and COD reduction from water/ wastewater.
Agro-industrial biorefinery effluent (AIBW) is considered a highly polluting source responsible for environmental contamination. It contains high loads of chemical oxygen demand (COD), and phenol, ...with several other organic and inorganic constituents. Thus, an economic treatment approach is required for the sustainable discharge of the effluent. The long-term process performance, contaminant removal and microbial response of AIBW to rice straw-based biochar (RSB) and biochar-based geopolymer nanocomposite (BGC) as biosorbents in an activated sludge process were investigated. The adsorbents operated in an extended aeration system with a varied hydraulic retention time of between 0.5 and 1.5 d and an AIBW concentration of 40–100% for COD and phenol removal under standard conditions. Response surface methodology was utilised to optimize the process variables of the bioreactor system. Process results indicated a significant reduction of COD (79.51%, 98.01%) and phenol (61.94%, 74.44%) for BEAS and GEAS bioreactors respectively, at 1 d HRT and AIBW of 70%. Kinetic model analysis indicated that the Stover-Kincannon model best describes the system functionality, while the Grau model was better in predicting substrate removal rate and both with a precision of between R2 (0.9008–0.9988). Microbial communities examined indicated the abundance of genera, following the biosorbent addition, while RSB and BGC had no negative effect on the bioreactor's performance and bacterial community structure of biomass. Proteobacteria and Bacteroidetes were abundant in BEAS. While the GEAS achieved higher COD and phenol removal due to high Nitrosomonas, Nitrospira, Comamonas, Methanomethylovorans and Acinetobacter abundance in the activated sludge. Thus, this study demonstrated that the combination of biosorption and activated sludge processes could be promising, highly efficient, and most economical for AIBW treatment, without jeopardising the elimination of pollutants or the development of microbial communities.
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•Emerging agro-industrial biorefinery wastewater treatment.•Utilizing biochar-based geopolymer nanocomposite for COD and phenol removal.•Microbial community analysis following RSB and BGC biosorbents addition.•Optimization by response surface methodology.•Kinetic modelling for COD and phenol removal.
•Optimization of chestnut shells extraction using response surface methodology.•Subcritical water extraction is a clean method for antioxidants extraction.•Optimum extraction conditions: temperature ...220 °C and extraction time 30 min.•Caffeoylquinic acid isomers were the main phenolic compounds.
The objective of this study was to evaluate the optimal Subcritical Water Extraction (SWE) conditions of antioxidants and polyphenols from chestnut shells using Response Surface Methodology (RSM). A central composite design (CCD) was conducted to analyse the time (6–30 min) and temperature (51–249 °C) effects in antioxidant activity (ABTS, DPPH and FRAP) and Total Phenolic Compounds (TPC). TPC ranged from 315.21 to 496.80 mg gallic acid equivalents (GAE)/g DW; the DPPH from 549.23 to 1125.68 mg Trolox equivalents (TE)/g DW; ABTS varied between 631.16 and 965.45 mg ascorbic acid equivalents (AAE)/g DW and FRAP from 2793.95 to 11393.97 mg ferrous sulphate equivalents (FSE)/g DW. The optimal extraction conditions were 30 min/220 °C, revealing excelling scavenging efficiencies against HOCl (IC50 = 0.79 µg/mL) and O2− (IC50 = 12.92 µg/mL) without toxicity on intestinal cells (0.1 µg/mL). The phenolic composition revealed high amounts of pyrogallol and protocatechuic acid. SWE can be a useful extraction technique for the recovery of polyphenolics from chestnut shells.
Response Surface Methodology (RSM) is used to optimize the conditions of the saponification reaction (Concentration of alkaline solution (%), temperature (°C) and reaction time (hour)). Level of ...foaming and durability of the emulsion (cleaning ability) from the product of the saponification reaction are two factors to evaluate the optimization process by RSM. After optimization, the alkaline solution concentration is 11%, the reaction was carried out for 2.5-3 hours at 85°C for the highest level of foaming and the most prolonged durability of the emulsion. This parameter was compared with the experiment, and the results showed that there was no significant error, this proves that the RSM model has good repeatability, can optimally correct and is essential in optimizing the survey parameters.
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•Successfully synthesized BAFPcPDIL heterogeneous photocatalysts and characterized.•Photo-catalytic esterification of alcohols with LA successfully carried out.•The catalyst shows ...admirable photocatalytic activity in the presence of 12 W LED light.•The numerical optimization examines the design expert software using RSM method.•Diesel blended with OL achieved admirable physical and emission properties.
NovelBrønsted acid functionalized phthalocyanine on perylene diimide framework knotted with ionic liquid (BAFPcPDIL) was synthesized and confirmed by instrumentation techniques. DRS-spectrum and Hammett value has been determined to confirm band-gap and proton levels of photo-catalyst respectively. The photo-catalytic performance was evaluated by production of octyl levulinate (OL) using levulinic acid (LA) with n-octyl alcohol (OA) under visible light irradiations. Response surface methodology (RSM)with Box–Behnken design (BBD) with 29 experiments was applied to explore consequences of four crucial process variables: catalyst loading (A), molar ratio of reactants (B) andpower of visible light (C), duration in hour (D) on OL yield. From the model, the optimum conditions for the utmost conversion were found as: 10 mg catalyst with (1:1) alcohol to LA molar ratio under 12 W lamp, in 12 h for completing esterification reaction with 95.58% yield of OL. With optimum conditions, various alkyl esters such as methyl levulinate 92.14%, ethyl levulinate 93.12%, n-propyl levulinate 91.45%, iso-propyl levulinate 92.38%, n-butyl levulinate 85.13%, n-pentyl levulinate 86.35%, n-hexyl levulinate 89.57%, tert-butyl levulinate 91.58%, were successfully synthesized with excellent yields. The plausible photocatalytic mechanismof the esterification reaction was also described. The study was extended on blending of OL with diesel sample in 10–30%, found comparable result of density, kinematic viscosity, calorific values, cetane number, flash, fire and pour point of the blended samples with blank diesel sample and appreciable changes in exhaust gases of 25% blended diesel sample. Additionally, BAFPcPDIL displayed good recyclability without loss of photo reactivity after four runs.
Microwave-steam activation (MSA), an innovative pyrolysis approach combining the use of microwave heating and steam activation, was investigated for its potential production of high grade activated ...carbon (AC) from waste palm shell (WPS) for methylene blue removal. MSA was performed via pyrolytic carbonization of WPS to produce biochar as the first step followed by steam activation of the biochar using microwave heating to form AC. Optimum yield and adsorption efficiency of methylene blue were obtained using response surface methodology involving several key process parameters. The resulting AC was characterized for its porous characteristics, surface morphology, proximate analysis and elemental compositions. MSA provided a high activation temperature above 500 °C with short process time of 15 min and rapid heating rate (≤150 °C/min). The results from optimization showed that one gram of AC produced from steam activation under 10 min of microwave heating at 550 °C can remove up to 38.5 mg of methylene blue. The AC showed a high and uniform surface porosity consisting high fixed carbon (73 wt%), micropore and BET surface area of 763.1 and 570.8 m2/g respectively, hence suggesting the great potential of MSA as a promising approach to produce high grade adsorbent for dye removal.
•Microporous activated carbon (AC) is made via microwave steam activation (MSA).•MSA shows short process time, fast heating rate, low temperature to produce AC.•Optimal yield and adsorption efficiency of AC at 550 °C and 10 min of heating.•85 wt% yield with 38.5 mg of dye/g of AC of adsorption efficiency were obtained.•Low production cost of AC (RM 2.90/kg) suggests the economical feasibility of MSA.
► AB1 dye biosorption was studied onto three brown macroalgae. ► Response surface methodology was employed to optimize the experimental conditions. ► Biomass dose, dye concentration and solution pH ...were found to be the main controlling parameters. ► The maximum dye removal efficiency was observed at pH 2.0.
Response surface methodology (RSM) based on three-variable-three-level Box–Behnken design was employed to interpret the adsorption characteristics of Acid Black 1 (AB1) dye onto three brown macroalgae viz.,
Nizamuddin zanardini,
Sargassum glaucescens and
Stoechospermum marginatum. The effects of three independent variables, viz. biomass dosage, dye concentration, and initial solution pH were studied for the removal of AB1 dye by the three macroalgae. A second-order polynomial model successfully described the effects of independent variables on the AB1 dye removal. The maximum experimental dye removal efficiency of 99.27, 98.12 and 97.62% for
N. zanardini,
S. glaucescens and
S. marginatum, respectively, was obtained, which was in agreement with the calculated values. The results of the present study suggest that these macroalgae can be used as an efficient biosorbents for dye removal from aqueous solution.
Big Data applications are typically associated with systems involving large numbers of users, massive complex software systems, and large-scale heterogeneous computing and storage architectures. The ...construction of such systems involves many distributed design choices. The end products (e.g., recommendation systems, medical analysis tools, real-time game engines, speech recognizers) thus involve many tunable configuration parameters. These parameters are often specified and hard-coded into the software by various developers or teams. If optimized jointly, these parameters can result in significant improvements. Bayesian optimization is a powerful tool for the joint optimization of design choices that is gaining great popularity in recent years. It promises greater automation so as to increase both product quality and human productivity. This review paper introduces Bayesian optimization, highlights some of its methodological aspects, and showcases a wide range of applications.
•Microencapsulated of lauric acid with a polystyrene shell was prepared.•A renewable and non-toxic phase change materials has been used for the process.•Emulsion polymerization has been applied as a ...microencapsulated technique.•Response surface method was applied to the statistical design.•The microencapsulated PCM had a good potential for energy storage system.
Thermal energy storage (TES) plays an important role in the development of an efficient solar energy system by storing the solar energy when available during the daytime and use it at night when required. The main component of a TES system is encapsulated phase change materials in macro, micro and nano sacles. Microencapsulated lauric acid (LA) as a renewable (obtained from vegetable oils) and non-toxic Phase Change Material (PCM) with a polystyrene shell was prepared using an emulsion polymerization technique. The individual and interactive effects of operating variables including lauric acid to styrene mass ratio, sodium dodecyl sulfate (SDS) to styrene (St) mass ratio, stirring rate and temperature on the microencapsulation ratio (ME.R) were investigated. Response surface method was applied to the statistical design, analysis of experiments and process optimization. Analysis of Variance (ANOVA) showed that the interaction between the stirring rate and temperature had non-significant effects on ME.R (%). The maximum achieved value of ME.R was 92.3% in the process optimization. It was enhanced compared with microencapsulation ratio of lauric acid in previous studies. By using the optimal values, LA/St mass ratio of 0.42, emulsifier (SDS) to styrene mass ratio of 0.01, stirring rate of 1076 rpm and the temperature of 55 °C, ME.R of 91.64% was obtained. Thermal properties, morphology and thermal stability of the optimal microcapsules were studied using DSC thermograms, Scanning Electron Microscopy (SEM) and thermogravimetry analysis (TGA), respectively. The results showed that microencapsulated renewable PCM with a melting point of 43.77 °C and latent heat of 167.26 kJ/kg has a good potential for utilizing renewable solar energy.
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