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In the present work, mathematical models relating mass density and specific volume of solution with concentration for aqueous solutions of anionic (sodium lauryl sulfate - SLS) and cationic (cetyltrimethylammonium bromide - CTAB) surfactants (0-10% (w/w)) have been investigated. The experimental studies were performed to study the effect of solution concentration on mass density and specific volume of solution. Mass density increases, and specific volume decreases with an increase in solution concentration for both surfactants. Linear, quadratic, cubic, quartic, quintic, and exponential models were fitted to the experimental data to check the applicability. The models were validated based on the coefficient of determination (R2) and the sum of square of error (SSE) to be unity and zero, respectively. Modelling results reveal that the quintic model was fitted to study the effect of density on solution concentration for both surfactants. KEY WORDS: Density, Surfactant, Cetyltrimethylammonium bromide, Sodium lauryl sulfate, Modelling, Regression Bull. Chem. Soc. Ethiop. 2023, 37(4), 1047-1054. DOI: https://dx.doi.org/10.4314/bcse.v37i4.19

Biodiesel is the fatty acid alkyl esters that are used as the substitute for petro-diesel. The aim of the present work is to optimize biodiesel production from plant based non-edible crude oils with methanol using heterogeneous catalyst by transesterification for its commercialization. The factors affecting the biodiesel production from plant oils are volume of feedstock (oil), volume of alcohol (excess reactant), quantity of calcium hydroxide (catalyst), reaction time, temperature, and agitation speed. Transesterification is the reaction between acid and alcohol to produce ester in the presence of alkali catalyst. In this work, transesterification was carried out between crude sunflower oil and methanol in the presence of calcium hydroxide as catalyst. Finally, the maximum conversion of 85.6% was achieved at the optimum process parameters of 2 L of crude sunflower oil, 0.3 L methanol, 23 g of calcium hydroxide, reaction time of 24 h, temperature of 65 °C, and agitation speed of 100 rpm. The results showed that crude sunflower oil could serve as potential renewable substrate for biodiesel commercialization.Biodiesel is the fatty acid alkyl esters that are used as the substitute for petro-diesel. The aim of the present work is to optimize biodiesel production from plant based non-edible crude oils with methanol using heterogeneous catalyst by transesterification for its commercialization. The factors affecting the biodiesel production from plant oils are volume of feedstock (oil), volume of alcohol (excess reactant), quantity of calcium hydroxide (catalyst), reaction time, temperature, and agitation speed. Transesterification is the reaction between acid and alcohol to produce ester in the presence of alkali catalyst. In this work, transesterification was carried out between crude sunflower oil and methanol in the presence of calcium hydroxide as catalyst. Finally, the maximum conversion of 85.6% was achieved at the optimum process parameters of 2 L of crude sunflower oil, 0.3 L methanol, 23 g of calcium hydroxide, reaction time of 24 h, temperature of 65 ?C, and agitation speed of 100 rpm. The results showed that crude sunflower oil could serve as potential renewable substrate for biodiesel commercialization.

Textile industries are the second largest water-consuming industries, next to agriculture. This research is aimed at investigating the utilization of fly ash as a low-cost adsorbent to treat hot wash liquor by employing one factor at a time. Contact time, effluent dosage, pH, mass of adsorbent, temperature, particle size, and agitation speed have been varied to find the optimum conditions for dye removal from hot wash liquor by fly ash. The results from the sorption process show that the maximum dye removal of 56.07% has been obtained at a time of 5 min, an effluent to water ratio of 9:1, pH of 11, an adsorbent dosage of 0.55 g/mL, a temperature of 27 °C, a fly ash particle size of 128 m and an agitation speed of 100 rpm. The analysis of the results was performed through adsorption capacity and percentage colour removal. Hence, the results suggested that fly ash could be used as an effective adsorbent for treating dyehouse effluents.

Citrus fruits contain sufficient citric acid, which is the main tricarboxylic acid. The properties of citric acid make it an important additive in various process industries. This experimental study aims to produce citric acid from orange and grape juices. The chemical route for the synthesis of citric acid from citrus juices involves three steps: (i) neutralization to adjust pH (9-11) with a 2.8 M NaOH solution, (ii) addition of CaCl2 solution (40.3-41.1% w/v), and (iii) acidification with an H2SO4 solution (1.5-2.3 M) to produce citric acid. In this study, the fruits were peeled, crushed, filtered, neutralized, added CaCl2 solution, and acidified to obtain citric acid. The experiments were carried out by varying the final pH of the solution and the concentrations of CaCl2 and H2SO4 solutions, maintaining the total volume constant. A maximum citric acid yield of 91.1% and 79.8% were achieved from orange and grapefruits, respectively, at the optimum final pH of the solution and the concentrations of CaCl2 and H2SO4 solutions at 10, 40.7% w/v, and 1.9 M, respectively. Finally, the purified citric acid crystals were characterized using FTIR and XRD. Thus, it could be concluded that orange fruit would be a promising source for citric acid production than grape.

Natural fibers are gaining popularity among researchers and academics for use in polymer composites due to their environmental friendliness and long-term viability.A new series of green composites ...

In this study, the methanol extract of Musa acuminate leaves has a significant development on the quality of the protection features such as, antibacterial and ultraviolet protection, was observed....

The current experimental study involves the synthesis and characterization of nanochitosan/sodium alginate composite (NC/Na-Alg) and utilized for the adsorptive removal of naphthalene from its aqueous solution. The NC/Na-Alg was primarily characterized using electron microscopy, Fourier transform spectrometer and X-ray diffractometer analysis. The operating process conditions such as pH, time, initial concentration, composite dosage and temperature were investigated on percentage degradation. The isotherm pattern and kinetic follow-up were fitted well with Freundlich mechanism and pseudo-second order, respectively, and the adsorption equilibrium capacity was estimated to be 55 mg/g. The thermodynamic analysis of adsorption revealed the physical and exothermic process. The column experiments produced optimum values at bed height, inlet flow rate of solution and initial naphthalene concentration of 150 mm, 10 mL/min and 50 mg/L, respectively. Also, the current study exhibited that the application of deacetylation method for NC/Na-Alg synthesis could be a productive approach for competing sequestration of naphthalene in the environment.

Artificial Neural Network (ANN) architecture contains three main (input, hidden and output) layers. The connections are established between layers through weights and bias. The various simulators are available to implement ANN. But, a knowledge on the numerical investigation and application of ANN for arbitrary values related by a nonlinear function is essential for the better understanding of a nature-inspired algorithm. Hence, the present manuscript provides the mathematical implementation of an algorithm for known values of independent and dependent variables, with and without bias. The predictability of ANN was assessed by a statistical parameter, mean squared error (MSE). The MSE by ANN algorithm was found to be higher (0.008) without bias than with bias for arbitrary values of independent and dependent variables. Hence, it could be concluded that the bias reduces error and enhances the predictability .

Inulin is a polysaccharide rich in good dietary fiber. Due to its increasing demand in the nutrition and pharmaceutical applications, industries are now looking out for alternative sources of inulin. This study focuses on extraction of inulin from garlic by solvent phase extraction method using water as solvent. The extraction parameters were optimized with temperature (60–90 °C), time (2–4 h), and material ratio (2–4 mL/g). The experiment was investigated by response surface methodology using central composite design. The results were statistically analyzed and graphically visualized. The quadratic model fitted well. The optimal conditions of factors, at 77.35 °C with 3.5 h of extraction time and material ratio of 5 mL/g resulted in maximum yield of 44.73 g/L. Temperature and material ratio showed more influence over the response yield. This study demonstrates the effective method of extraction of inulin from garlic.

The current study involves the synthesis of Lantana camara (LC)–incorporated mesostructured iron nanoparticles for the removal of nickel ions from aqueous solution. By systematically varying the operational parameters such as metal ion concentration, pH, adsorbent dosage, contact time, and temperature, the desirable conditions of adsorption were determined. The favorable adsorption at higher temperatures implies that the system is exhibiting endothermic reactions and the Van’t Hoff plot suggested the spontaneous and feasible nature of the adsorption process. Another key point is the fast kinetics of the sorption process that occurred in the first 10 min of sorption processes. Among the kinetic models investigated, the sorption is better explained by pseudo-second-order model favoring chemical adsorption. Furthermore, the complexation of nickel ions with –COOH groups of the LC nanoparticles are confirmed in the FTIR studies and the mesoporous (162.1 A°) nature of nanoparticles are confirmed in the BET analysis. From the VSM analysis, the superparamagnetic nature of the mesoporous nanoparticles were revealed. Another important finding from the VSM results is the high saturation magnetization (66.9 emu/g) of the nanoparticles. Equally important is desorption studies where a maximum efficiency of 81% is obtained using 05 N HCl. With the help of the Langmuir modeling studies, the possible mechanism of sorption are explained and more importantly the monolayer adsorption capacity from the model was found to be 133 mg/g.

The intention of this present study is to optimize the recovery of pectin from Persea americana peel (PAP) examining four independent process variables (pH, solvent to substrate ratio (SSR) (ml/g), agitation time (AGT) (h), and agitation speed (AGS) (rpm)) and compare the pectin recovery (PR) using statistical (Box-Behnken response surface design (BBRESD)) and non-statistical (artificial neural network (ANN) with genetic algorithm (GA)) methods. Optimal condition derived in ANN-GA (pH of 1.9, SSR of 16 ml/g, AGT of 2.1 h, AGS of 99 rpm, and PR of 90.59%) has forecast PR very precisely than BBRESD (pH of 2, SSR of 14 ml/g, AGT of 2 h, AGS of 100 rpm, and PR of 85.44%). Extrapolative capacities of two methods were examined by several statistical restraints. Structural analysis (FT-IR and XRD) of PR was exhibited that highly esterified and amorphous nature of pectin was recovered from PAP. Recovered pectin was melted at the temperature of 258.5 °C which was similar to commercial pectin. SEM observations revealed that recovered pectin was flake and spherical particle. The results of this work suggested that pectin from PAP is one of the good sources to recover pectin with good quality as commercial pectin and used as a food ingredient.

Research & Reviews in Biotechnology & Biosciences ISSN No: 2321-8681 Website: www.biotechjournal.in Review Paper Volume-8, Issue No: 1, Year: 2021 (January-June)&nbsp

The feasibility of using Eucalyptus citriodora leaves (ECL), an abundantly available agricultural waste, for adsorption of an anionic dye, direct red 31 (DR31), adsorption from hydrous solution has been examined in the present research. The batch adsorption trials were performed to analyse the effects of pH, contact time, initial dye concentration, adsorbent dose, temperature and particle size on DR31 removal from its aqueous solution on biochar of ECL. A maximum of 97% removal of DR31 dye was observed at pH and initial adsorbate concentration of 2 and 40 mg/L by the ECL biochar, respectively. Equilibrium data were examined by Langmuir and Freundlich isotherms. Langmuir isotherm appeared as the best fit model with the highest adsorption capacity of 3.2 mg/g. The kinetic results were also examined and found pseudo-second-order to be the best fit which expressed that the adsorption rate was mainly regulated by chemisorption. ECL biochar maintained > 41.56% adsorption capacity of DR31 dye even after five adsorption–desorption consecutive cycles. Phytotoxicity studies on Vigna radiata substantiated the non-toxic nature of the treated DR31 dye-containing water. The present study reveals that the biochar of ECL can be utilized as a cost-effective adsorbent to make the dye-contaminated wastewater reusable.

Pollution is a major issue impacting the health of life and ecosystems. In particular, some pollutants may alter gene expression by epigenetic mechanisms such as deoxyribonucleic acid (DNA) methylation, histone modifications, and microRNA (miRNA) expression. Epigenetics is the study of heritable changes without alteration in the DNA sequence. In the healthy state, the coordinated actions of interconnected epigenetic factors are responsible for proper cell development and cell regulation. Epigenetic mechanisms are tissue-specific; hence, a pollutant may or may not cause an alteration depending on the type of tissue. Here we review mechanisms by which pollutants disrupt epigenetic factors. We focus on the impact of arsenic, cadmium, nickel, mercury, benzene, bisphenol A, dioxin, hexahydro-1,3,5-trinitro-1,3,5-triazine and diethylstilbestrol. A list of diseases related to epigenetic factors and heavy metals exposure is provided.

In this work, a novel citrate stabilised electroless bath was developed and the process parameters (concentrations of nickel, reducing agent, and stabiliser) were optimised to achieve the maximum hardness in the ENi-B deposit on 7075-T6 aluminium alloy, using the back-propagation neural network (BPNN), Box–Behnken design (BBD), simulated annealing (SA) and genetic algorithm (GA). The effect of independent variables on dependent variable was modelled using the BPNN and BBD. The models were assessed for their significance using the coefficient of determination (R2) and mean squared error (MSE). The MSE and R2 of 34.18 and 0.9852 were obtained for BPNN model against 20.48 and 0.9911 for BBD, which proved that the BBD fits well to the experimental data. The optimum nickel ion, reducing agent and stabiliser concentrations of 29.86, 0.77 and 30.92 g L−1 were obtained from BBD for the maximum hardness of 592 HV. The local optimum values obtained from BBD were compared with global optimisation techniques, SA and GA, and the values were validated through experiments carried out in triplicate. The maximum hardness from local and global optimisation techniques was identical, with negligible change in the values of optimised process parameters. X-ray diffraction and scanning electron microscopy methods were used to examine the elemental composition and surface morphology, respectively, before and after heat treatment.

Biogas, an alternative to fossil fuels, is a blend which consists predominantly of CH4 and CO2 used for transportation and collective heat as well as power (CHP) generation. The factors affecting biogas manufacture are characteristics of substrate (especially C/N and VSS/TSS ratios), concentration of substrate in feed, process temperature, retention time, working pressure, and pH of feed. Biogas is produced by anaerobic digestion, in which biopolymers are transformed to biogas in the nonappearance of O2. This digestion process is essentially anaerobic which contains four major steps. These are hydrolysis of polymer, acidogenesis, acetogenesis, as well as methanogenesis. Hydrolysis involves the breakdown of biopolymers to its monomers with the help of water. Acidogenesis involves the formation of acids, which are essentially volatile, from the monomers. Acetogenesis produces acetates and acetic acid from various volatile acids. Finally, acetates and acetic acid are converted to methane and carbon dioxide during methanogenesis. Anaerobic digestion takes place in the presence of co-culture containing hydrolytic, acidogenic, acetogenic, and methanogenic organisms. In this chapter, a comprehensive review on the development of hydrolytic, acidogenic, acetogenic, and methanogenic organisms for biogas production is presented.

Biodiesel is a renewable and clean-burning fuel used as a substitute for petroleum diesel. Biodiesel, as a biofuel, increases energy security and environment quality and provides safety benefits. The objective of this chapter is to study the effectiveness of various lime-based materials as catalysts for the preparation of biodiesel from crude sunflower oil through transesterification with methanol and ethanol. First, biodiesel was prepared from pure sunflower oil using methanol and NaOH as a catalyst. Then, biodiesel was prepared from pure sunflower oil using ethanol and rejected lime as a catalyst. Later, biodiesel was prepared from crude sunflower oil using methanol and various lime-based materials such as rejected lime, pure lime, and limestone as catalysts. Biodiesel was checked for its properties such as free fatty acid, density, dynamic viscosity, kinematic viscosity, flash and fire points, and cloud and pour points. From the results, it was found that pure lime is the suitable catalyst for the production of biodiesel from crude sunflower oil. A concise review on biodiesel production using lime-based materials as a catalyst was also presented.

Biodiesel attracts much attention among researchers due to utilization of residual oils and fats as feedstocks and solid materials as heterogeneous catalysts. A transesterification between triglyceride and alcohol with a catalyst produces biodiesel. The aim of the chapter is to present the mathematical modelling and process simulation of transesterification reaction from non-edible yellow oleander (Thevetia peruviana) oil and waste chicken fat. Seeds of T. peruviana were collected, extracted oil and reacted with methyl alcohol and ethyl alcohol using alkaline potassium hydroxide as a catalyst to produce biodiesel. Oil was extracted from waste chicken fat and reacted with methyl alcohol using Candida rugosa lipase as a catalyst to produce biodiesel.

The laser cladding technique is useful for enhancing the surface performance and extending the life of many components in severe wear and corrosive environments. The aim of the present study is to develop a model relating independent variables, laser power (2200–2800 W), powder-feed rate (30–50 g/min), laser-scanning speed (800–1200 mm/min) and the focal position of the laser beam (15–35 mm), with the dependent variable, Vickers hardness number, and optimize the process parameters to achieve maximum hardness in CO2 laser cladding of Inconel 625 powder on AISI 304 SS substrate. The models were developed using curve fitting and artificial neural network (ANN) models by fitting the experimental data and comparing the predicted values from the models with the experimental values. The model developed by curve fitting method was employed to optimize the hardness using first derivative test, generalized reduced gradient (GRG) and grey-relational analysis (GRA). The maximum hardness of 374 was achieved by first derivative test at optimal laser power, powder-feed rate, laser-scanning speed, and the focal position of the laser beam of 2554 W, 999 mm/min, 30 mm and 40.5 g/min, respectively.

A stoichiometric analysis of biogas production by anaerobic digestion from cassava wastewater, wheat bran, and sewage sludge is proposed. A wide range of methods are available to study stoichiometry of biochemical reactions. This work reported elemental balances method to solve stoichiometric coefficients in biogas production from cassava wastewater, wheat bran, and sewage sludge. The method could be employed for various substrates for biogas production and for other biochemical reactions.

Aerobic digestion is the process of breaking down of larger molecules to smaller molecules in the presence of oxygen. The manuscript presents a comprehensive review of experimental studies on aerobic digestion of wastewater sludge. In the review section, the manuscript presents an overview of developments in aerobic digestion of wastewater sludge. In the experimental studies, municipal sewage sludge was digested in the presence of oxygen by using dry yeast as a catalyst. Batch experiments were carried out in Armfield aerobic digester to maximize the reduction in VSS by optimizing the process parameters such as digestion time, air flowrate, concentration of sludge, and pH of feed at the constant temperature of 35°C.

Pyrolysis is used to produce bio-char, bio-oil and syngas from industrial residues through thermochemical processing route. Pyrolysis decomposes biomass at an elevated temperature in an inert atmosphere. The aim of this study is to develop a model and evaluate activation energy for pyrolysis of teak sawdust. Teak sawdust was pyrolysed at four different temperatures from 300 to 600 °C. The mathematical model was developed for pyrolysis of teak sawdust. Kinetic constants were calculated by fitting the data from pyrolysis experiments to the model. Activation energy was determined from Arrhenius equation which related kinetic constant and temperature. The results reveal that pyrolysis of waste biomass, teak sawdust, could be the effective thermochemical route for bioenergy.

Curcuma caesia commonly known as Black turmeric exhibits high medicinal properties due to the presence of bioactive compounds. The rhizomes of Curcuma caesia was extracted with organic solvent such as ethanol using cold percolation method. The main objective of this study was carried out in order to find the best suitable condition for the extraction of total polyphenols. Total polyphenols are compounds which includes flavonoids, phenolic acids, stilbenes and lignans. The effects of extraction of total polyphenols involving extraction time, particle size and L/S ratio were evaluated and optimized using Box-Behnken design (BDD) a well-known response surface methodology. The results obtained from the experiments were subjected to analysis of variance (ANOVA) and analysed using polynomial equation. From the results, it was found that further optimization studies need to be carried out for effective extraction of total polyphenols.

Biochar was prepared from waste Gossypium hirsutum seeds using microwave activation and were used as adsorbent for copper (II) removal from aqueous solution. The main and interactive properties of biochar dosage (1–3 g/L), initial copper (II) concentration (5–15 mg/ L), pH (2–12) and temperature (20–40°C) were examined using Box– Behnken surface methodology. The statistical analysis indicated good fit of the experimental data with correlation coefficient (R2=0.9997), F–value (3929.31), coefficient of variation (0.61), and adequate precision (200.89). Nonlinear optimization indicated that 100% removal of copper could be achievable at biochar dosage 2.1 g/L, initial copper concentration 10.72 mg/L, pH 8.2, and temperature 28.69°C.

Dyes are the major pollutants in the waste waters which are mainly from textile industries. Though large number of treating methods available each has its demerits. Synthetic dyes used for the dyeing process increase the rate of water body pollution due to the discharge from the industries. Liquid-membrane extraction is a (LME) suitable technique for dye removal dude to its simple and easy design. Recalcitrant surfactants are the only hindrance faced in the LME which can be overcome by suitable biosurfactant. Hence in this work methyl orange is taken as model dye pollutant and saponin extracted from palm oil was used as biosurfactant. Central composite design (CCD) was utilized to optimize the extraction parameters such as concentration of methyl orange (100-200 mg/L), concentration of the surfactant (1-3 mg/L), and solvent ratio (1:1-1:3 mg/L) were examined and extraction efficacy was maximized.

Thermal kinetics of the antimicrobial metabolite relies on adequate degradation kinetic models to warrant food safety and quality. Thermal inactivation of bacteriocin is necessary for its use as natural biopreservatives in the food industry. In this work, the kinetics of thermal inactivation was studied for partially purified bacteriocin produced by Pseudomonas aeroginosa isolated from fermented oats. Samples of bacteriocin were treated at temperature (45-65°C) at constant time of 80 min and different time (0-120 min) at constant temperature of 55°C. The kinetic and thermodynamic parameters for bacteriocin inactivation were calculated. The inactivation was found to follow first order kinetics with k values increase with increase in temperature. Half-life and death rate of the strain producing bacteriocin were also estimated. In addition, frequency factor, activation energy, enthalpy, entropy and Gibb's free energy were determined.

Adsorbent was prepared from waste cotton seeds and utilized to remove acetaminophen from aqueous solutions. The main and interactive effects of five process variables such as, adsorbent dose, initial acetaminophen concentration, contact time, pH and temperature were investigated via response surface methodology based on Box-Behnken statistical design. The optimum values of the selected variables were estimated using Derringer’s desired function. The batch adsorption data obeyed smith isotherm. Kinetic investigation showed that the acetaminophen was chemisorbed on waste cotton seed activated biomass surface following pseudo second order model. The fixed-bed adsorption breakthrough curves at different bed heights were well correlated by BDST model. Exhausted adsorbent could be regenerated eight times efficiently using microwave irradiation.