Global outlook of biofuels turns out to be a full-fledged search focusing the viability and sustainability assets. The present day option for immediate and sustainable alternate fuels lies with algal ...biofuels. Algae are the most sustainable fuel resource in terms of food security and environmental issues. Inefficient and unsustainable biofuel derived from food crops twosome food security issues thus increasing interests towards algal energy. CO2 mitigation, quick biomass accumulation accomplishing simultaneous bioremediation have gathered progressive attention. Cultivation of biomass, harvesting, processing and fuel production by chemical/biochemical reactions are the sequential stages in algal biofuel production. Currently, biofuels produced from algal biomass is not economical since biomass cultivation, processing and separation of fuel products appears costly although certain advancements in culturing techniques have been recently unearthed. Further improvements with the biomass processing strategies may step up the third-generation biofuel concept a profitable one in the near future. This article reviews various cultivation methods, processing techniques and stages in algal biofuel production thereby extensively investigating their potential application in biofuel refineries.
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•Annona squamosa seed oil was found as a new source for biodiesel production.•Ultrasound assisted extraction of oil was assessed to extract >94%•Optimized the ultrasound assisted ...extraction and transesterification using RSM.•Conversion ratio of annona squamosa seed oil to biodiesel was evaluated as >95%
In this work, Annona squamosa seed oil (ASSO) was extracted using ultrasound-assisted extraction (UAE) and converted into fatty acid methyl esters (FAME) by ultrasound-assisted transesterification (UAT) using methanol and KOH. The multivariable process of UAE and UAT was optimized using a response surface methodology (RSM). The experimental data were analyzed by Pareto analysis of variance (ANOVA) and quadratic polynomial models developed using non-linear regression analysis. A maximum ASSO yield of 31.91% was achieved by the model with the optimum conditions for UAE: liquid-to-solid ratio, 8.8 mL g−1; extraction temperature, 45 °C; sonication time, 19.5 min; and sonication amplitude, 88%. The maximum conversion of ASSO into biodiesel (97.6%) was achieved with the optimum condition of the model: oil-to-methanol ratio, 5.04; catalyst concentration, 1.12%; temperature, 57 °C; and sonication time, 113 min. These models were found to be significant at the 95% confidence level. The transesterified ASSO FAME was characterized using Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), gas chromatography mass spectrometry (GC–MS), 1H-nuclear magnetic resonance (1H NMR), and fluorescence spectroscopy methods. Various physicochemical properties of ASSO and ASSO FAME were characterized according to ASTM standards. The ultrasound-assisted extraction and transesterification process was found to be rapid and simple without any change in the product quality. Importantly, ASSO was found to be a possible new source for potential biodiesel production.
Scientists and engineers have experimentally noticed that the heat transfer is essential for preeminence of multi scale production. Thermal properties are naturally accomplished via continuous phase ...liquids. Its importance is nevertheless constrained by the low capacity for heat transfer. Consequently, the increased heat transference phenomenon must be employed to accomplish the expected results. In this regard, the nature of the Arrhenius activation energy in the flow of hybrid nanoliquid over a curved stretchable surface (CSS) in the presence of exponential heat generation is scrutinized. The fluid suspended with Manganese zinc ferrite (MnZnFe2O4) and Nickel zinc ferrite (NiZnFe2O4) as nanoparticles along with Kerosene oil as a base liquid is accounted in this study. The described flow equations are transformed by using appropriate similarity variables and then they are tackled with Runge Kutta Fehlberg‐45 (RKF‐45) scheme by adopting shooting process. It can be concluded that, the increasing values of Biot number and heat source/sink parameter improves the thermal gradient. Further, hybrid nanofluid shows high heat transfer rate when compared to nanoliquid for improved values of heat source/sink parameter.
Scientists and engineers have experimentally noticed that the heat transfer is essential for preeminence of multi scale production. Thermal properties are naturally accomplished via continuous phase liquids. Its importance is nevertheless constrained by the low capacity for heat transfer. Consequently, the increased heat transference phenomenon must be employed to accomplish the expected results. In this regard, the nature of the Arrhenius activation energy in the flow of hybrid nanoliquid over a curved stretchable surface (CSS) in the presence of exponential heat generation is scrutinized.…
A tubular ceramic microfiltration membrane was prepared by an extrusion technique using inexpensive clay mixtures namely, ball clay, kaolin, feldspar, quartz, pyrophyllite and calcium carbonate. The ...mixture of clay powders extruded to form a porous tubular membrane without the addition of any organic additives. The dimensions, such as outer and inner diameters, wall thickness and length of the tube are 11.5, 5.5, 3 and 100mm, respectively. The sintered membrane possesses the porosity of 53%, water permeability of 5.93×10−7m/skPa, an average pore size of 0.309μm and mechanical strength of 12MPa with very good corrosion resistance in acidic and basic conditions. The fabricated membrane is expected to have potential applications in the pretreatment and also can be used as support for ultrafiltration membranes. With this intention, the membrane is subjected to microfiltration of synthetic oily wastewater emulsion experiments at various combinations of applied pressures (69–345kPa), feed concentrations (50–200ppm) and cross flow rates (5.55×10−7–1.66×10−6m3/s). An increase in the applied pressure and flow rate of oily wastewater emulsion result a decreased oil rejection while, an increase in the oil concentration results in enhanced rejection. The applied pressure of 69kPa offers the highest rejection of oily wastewater (99.98%) with permeate flux of 3.16×10−5m/s. Additionally, the membrane fouling mechanisms are investigated using diverse pore blocking models (complete, standard, intermediate pore blocking and cake filtration model) with obtained experimental data. It is found that the experimental results are well described by the cake filtration model. Finally, the rejection potential of the membrane is compared with other membranes reported in the literature.
•Novel low cost tubular membrane effectively elaborated by extrusion.•Performance checked in treatment of oily wastewater emulsion.•Highest rejection of 99.98% attained with permeate flux of 3.16×10−5m/s.•Fouling mechanisms analyzed using various models.
The economically significant production of carbon-neutral biodiesel from microalgae has been hailed as the ultimate alternative to depleting resources of petro-diesel due to its high cellular ...concentration of lipids, resources and economic sustainability and overall potential advantages over other sources of biofuels. Pertinent questions however need to be answered on the commercial viability of large scale production of biodiesel from microalgae. Vital steps need to be critically analysed at each stage. Isolation of microalgae should be based on the question of whether marine or freshwater microalgae, cultures from collections or indigenous wild types are best suited for large scale production. Furthermore, the determination of initial sampling points play a pivotal role in the determination of strain selection as well as strain viability. The screening process should identify, purify and select lipid producing strains. Are natural strains or stressed strains higher in lipid productivity? The synergistic interactions that occur naturally between algae and other microorganisms cannot be ignored. A lot of literature is available on the downstream processing of microalgae but a few reports are available on the upstream processing of microalgae for biomass and lipid production for biodiesel production. We present in this review an empirical and critical analysis on the potential of translating research findings from laboratory scale trials to full scale application. The move from laboratory to large scale microalgal cultivation requires careful planning. It is imperative to do extensive pre-pilot demonstration trials and formulate a suitable trajectory for possible data extrapolation for large scale experimental designs. The pros and cons of the two widely used methods for growing microalgae by photobioreactors or open raceway ponds are discussed in detail. In addition, current methods for biomass harvesting and lipid extraction are critically evaluated. This would be novel approach to economical biodiesel production from microalgae in the near future. Globally, microalgae are largest biomass producers having higher neutral lipid content outcompeting terrestrial plants for biofuel production. However, the viscosities of microalgal oils are usually higher than that of petroleum diesel.
Fins are widely used in many industrial applications, including heat exchangers. They benefit from a relatively economical design cost, are lightweight, and are quite miniature. Thus, this study ...investigates the influence of a wavy fin structure subjected to convective effects with internal heat generation. The thermal distribution, considered a steady condition in one dimension, is described by a unique implementation of a physics-informed neural network (PINN) as part of machine-learning intelligent strategies for analyzing heat transfer in a convective wavy fin. This novel research explores the use of PINNs to examine the effect of the nonlinearity of temperature equation and boundary conditions by altering the hyperparameters of the architecture. The non-linear ordinary differential equation (ODE) involved with heat transfer is reduced into a dimensionless form utilizing the non-dimensional variables to simplify the problem. Furthermore, Runge-Kutta Fehlberg's fourth-fifth order (RKF-45) approach is implemented to evaluate the simplified equations numerically. To predict the wavy fin's heat transfer properties, an advanced neural network model is created without using a traditional data-driven approach, the ability to solve ODEs explicitly by incorporating a mean squared error-based loss function. The obtained results divulge that an increase in the thermal conductivity variable upsurges the thermal distribution. In contrast, a decrease in temperature profile is caused due to the augmentation in the convective-conductive variable values.
•Rare earth element Ce3+ doped CoFe2O4 NPs were prepared by simple sol-gel combustion technique.•Cerium was successfully substituted into the spinel lattice without any distortion.•Powder XRD and SEM ...along with EDX studies confirmed the pure phase formation.•There was a substantial decrease in the crystallite size on doping with Ce3+.•Magnetic properties altered by the addition of Ce3+ in the CoFe2O4 matrix.
In this present study, we made an attempt for the different concentration of rare earth element (REE) Cerium (Ce3+) doped cobalt ferrite (CoFe2O4) nanoparticles (NPs) were prepared by the simple sol-gel combustion technique. Cerium was successfully substituted into the spinel lattice without any distortion. It was analyzed the effect of Ce3+ ions doping on structural, morphological, magnetic properties and antibacterial activities using the various instrument techniques. Powder XRD and SEM along with EDX studies confirmed the pure phase formation Ce3+ doped CoFe2O4 NPs and spherical shaped agglomerated nanoparticles morphology without any other impurity. The well resolved broad peaks in the XRD pattern clearly indicated the nanosized, single phased, cubic spinal nature of these samples. There was a substantial decrease in the crystallite size on doping with Ce3+. A more in-depth morphological study was facilitated using the TEM and SAED analysis. TEM investigation revealed random shaped, sharp edged nanoparticles with a normally facetted morphology. The presence of distinctive diffractions spots on the SAED pattern indicated the formation of nanoparticles that are highly crystalline in nature. The magnetic response of the Ce3+ doped CoFe2O4 NPs was recorded at room temperature (RT) using the VSM technique. The magnetic properties have been seen to be altered by the addition of Ce3+ in the CoFe2O4 matrix. The decrease in the saturation magnetization (Ms, emu/g) with the increase in Ce3+ content rendered the synthesized sample applicable in field of antenna construction. This change will be also suitable for reducing the size of the antenna. The antibacterial activity of Ce3+ doped CoFe2O4 nanoparticles was found to be enhanced with increase in Ce3+ doping level as it cause a reduction in the grain size.
The electrocatalytic reduction of carbon dioxide at Cu based metal organic framework film surface was studied in N,N-dimethylformamide containing tetrabutylammonium tetrafluoroborate with saturated ...CO2. Cyclic voltammetric studies of the MOF film immobilized onto GC in 0.1MKCl clearly showed the well defined Cu(II)/Cu(I) and Cu(I)/Cu(0) reversible redox responses. In the presence of saturated CO2/TBATFB/DMF solution, the cyclic voltammetric studies revealed that the electrochemically generated Cu(I) formed adduct with carbon dioxide in-situ and on further formed oxalic acid. The formation of oxalic acid was confirmed by GCMS in bulk electrolysis experiment. A detailed mechanism for the formation of oxalic acid was also discussed in this communication.
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This study investigated the removal of two widely used antibiotics, norfloxacin (NOR) and ofloxacin (OFL) from aqueous solution by employing a novel integrated adsorption cum membrane filtration ...process. The application potential of the adsorbent was investigated by evaluating the effect of different process parameters; including solution pH, initial antibiotic concentration and adsorbent dosage. Among these parameters, solution pH significantly affected the removal of antibiotics due to its strong effect on the charges of the adsorbent and the adsorbate. The removal efficiency decreased with an increase in the initial antibiotics concentration and increased with an increase in the adsorbent amount. A maximum removal of 98.7% for NOR and 94.61% for OFL was achieved with 10mg/L initial concentration and at a solution pH of 7. A high removal of NOR as compared with that of OFL was attributed to a high steric hindrance of OFL due to its bulky structure. The adsorption kinetic data for both the antibiotics followed the pseudo second order kinetics, and the sorption isotherm data was best described by the Langmuir model. Further, adsorption of the two antibiotics involved a combination of electrostatic interaction, anion exchange and hydrophobic interaction mechanisms. The FTIR spectrum of the modified LDH obtained before and after adsorption confirmed the adsorbate-adsorbent interaction. Finally, the microfiltration technique using a ceramic membrane was effectively employed to separate the loaded adsorbent from solution to recover and reuse the adsorbent with an aim to reduce the overall cost of the adsorption process.
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•Hybrid adsorption cum membrane microfiltration introduced for antibiotics removal•SDS modified Ni-Al LDH contributed as an adsorbent to wastewater treatment.•Low cost microfiltration membrane applied to reduce the overall operation cost•Modified LDH is better for adsorption of NOR (98.7%) and OFL (94.6%).•Established scheme can be employed efficient removal of fluoroquinolone antibiotics.
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