Evaluation of adsorption and kinetics of neem leaf powder (Azadirachta indica) as a bio-sorbent for desulfurization of dibenzothiophene (DBT) from synthetic diesel

The need for a sustainable environment has necessitated the development of a green adsorbent that is efficient, cheap, and readily available to serve as an alternative adsorbent for the removal of the refractory sulfur-containing compound from diesel. In this current study, neem-leaf powder (NLP) was activated using H2SO4 and tested in desulfurization adsorption experiments of synthetic diesel containing Dibenzothiopene (DBT) during a batch operation. The synthetic diesel contained 0.1 g of DBT in 100 mL of hexane. Before testing, physio-chemical characteristics of the adsorbent were checked via Fourier transmission infrared (FTIR) spectroscopy for surface chemistry; via N2 physisorption at 77 K for textural properties; SEM quipped with EDX for morphology and elemental composition; and XRD for purity and crystallinity. The results showed that the physico-chemical nature of the adsorbent played a significant role in enhancing the adsorption capacity of the material for DBT. Activated NLP displayed DBT removal of 65.78% at 30 °C using 0.8 g of the adsorbent. Furthermore, the behaviour of the adsorbent during the adsorption could be adequately described using the Freundlich isotherm model. Pseudo-first-order and pseudo-second-order kinetics model describe well the adsorption kinetics of DBT onto the activated NLP.L’Oréal-UNESCO foundation for Women in Science, Sub-Saharan African Fellowship.https://www.sciencedirect.com/journal/journal-of-saudi-chemical-societyhj2023Chemical Engineerin

Performance evaluation of green adsorbent (neem leaf powder) for desulfurization of petroleum distillate

The release of sulfur-containing compounds during direct combustion of diesel fuel has caused environment issues which require urgent attention. Recently, stringent environmental regulations by the Environmental Protection Agency (EPA) to minimise the total sulfur-containing compounds released into the atmosphere have intensified the research in this area. In this present study, adsorption experiments in batch mode were conducted using an activated green adsorbent (Neem leaves powder) to reduce the amount of dibenzothiophene (DBT) in a synthetic oil. The synthetic oil was prepared by dissolving 0.1 g of dibenzothiophene (DBT) in 100 mL of hexane. Various analytical techniques were used such as; Scanning electron microscopy (SEM) to check the morphological structure of the adsorbent. Nitrogen adsorption and desorption experiments (Brunauer-Emmett-Teller, BET) at 77 K were used to check the surface area, pore size and pore volume of the adsorbent. N2 physio-sorption at 77 K before and after adsorption showed adsorption of DBT molecules onto the surface of the adsorbent after adsorption experiment. The results showed about 65.78 % removal of DBT at temperature of 30o C and adsorbent amount of 0.8 g. Therefore, neem leave powder could be an alternative cheap adsorbent to reduce the concentration of organo-sulfur compound in petroleum distillates. This may offer new perception into the development and application of green materials in sustainable, innovative and effective waste management and abatement of environmental pollution.L’Oréal-UNESCO foundation for Women in Science, Sub-Saharan African Fellowship.http://www.cetjournal.itpm2021Chemical Engineerin

Synthesis of PET-Magnesium Oxide-Chitosan Nanocomposite Membranes for the Dehydration of Natural Gas

Flat thin-film magnesium oxide-chitosan nanocomposite membranes were synthesized with polyethylene terephthalate (PET) and employed for natural gas dehydration. The water vapor permeation was most pronounced with a nanocomposite membrane doped with 0.9 g MgO nanoparticles (NP) as a result of a significant upsurge in the permeability of water vapor in the membrane (0.87). With the increase in MgO NP, large macro-voids are created, substratum pore size, and thickness together with the water vapor permeation were upsurged. The dehydration of natural gas performance of magnesium oxide-chitosan nanocomposite membranes synthesized with PET was enhanced with the increase in MgO NP embedded in the membrane. Though water vapor permeation was restricted by the polyester non-woven material used as a support for the nano composite membranes, as the three membranes did not reach the permeation coefficient of 1. However, the permeation coefficient increased with an increased MgO NP, with three mambrane samples (M1, M2 and M3) having permeation coefficient of 0.763, 0.77 and 0.87 respectively. The gas reduced with an increase MgO NP, with M1, M2 and M3 having 3.46×10−2, 3.17×10−2 and 3.88×10−3 kg/m3 respectively. From the adsorption study, the discrepancy observed between CH4 and vapor with isotherm models was ascribed to the different adsorption behavior of CH4 and vapor on the membrane-active area. The cost of making the membrane cannot be considered as a terminal criterion because most of the cost-effective option is not always the optimum one. The membranes confirmed their suitability for the dehydration of natural gas

A comparative evaluation of fermentable sugars production from oxidative, alkaline, alkaline peroxide oxidation, dilute acid, and molten hydrate salt pretreatments of corn cob biomass

Production of high value-added products from lignocelluloses is an economically sustainable alternative to decreasing dependence on fossil fuels and making the chemical processes environmentally friendly. In this study, different methodologies of alkaline (Ca(OH)2 and NaOH), dilute acid (10%w/w H2SO4), hydrogen peroxide (H2O2), alkaline peroxide oxidation (H2O2/Ca(OH)2 and H2O2/NaOH), and molten hydrated salt (MHS) mediated (ZnCl2.4H2O) pretreatments were employed in the hydrolysis of corncob amenable to enzymatic hydrolysis. Optimal enzyme hydrolysis temperature (considering 45 and 50 ℃) and time (2, 24, 72, and 96 h) were investigated for each pretreatment procedure to ascertain the concentrations of glucose, xylose, and total sugar present in the corncob. At 45 ℃ and 96 h, NaOH alkaline pretreatment achieved the best optimum total sugar production of 75.54 mg/mL (about 54% and 88% increments compared to dilute acid pretreatment (35.06 mg/mL total sugars) and MHS (9.32 mg/mL total sugar) pretreatment respectively). In this study, total sugars production increased appreciably at 45 ℃ and longer hydrolysis period (96 h) compared to hydrolysis at 50 ℃ (with maximum total sugars production of 18.00 mg/mL at 96 h). Scanning electron microscopic imaging of the untreated and treated samples displayed cell wall distortion and surface disruptions.Covenant University, Ota, Nigeria.http://www.aimspress.com/journal/energypm2021Chemical Engineerin

Development of non-derivatizing hydrate salt pre-treatment solvent for pre-treatment and fractionation of corn cob

Major concern in beneficiating lignocellulose is overcoming biomass recalcitrance through pre-treatment. Molten hydrate salts (MHS) is a green solvent with ability to swell and dissolve cellulose and biomass in a non-derivatizing way. Over the last decade, MHSs have been used for isolated cellulose dissolution, however very few studies have been reported on their effectiveness in pre-treating lignocellulosic biomass. Therefore, effectiveness of their application as solvent for pre-treating and fractionating corn cob is presented in this article. In this study, seven molten hydrate salt pre-treatment solvent systems such as unary, binary and ternary mixtures of ZnCl2.4H2O, LiClO4.3H2O and Urea were investigated for their ability to pre-treat and fractionate biomass. The pre-treatment experiments were carried out in a shaking incubator at 70°C for 60 minutes at a biomass: solvent ratio of 1:10. The surface chemistry of the biomass was checked before and after pretreatment using Fourier Transform infrared spectroscopy. X-ray diffraction and scanning electron microscopy were employed to check the crystallinity and surface morphology of the biomass. Physicochemical analysis consistently indicated a disruption in the structure of corncob due to removal of lignin and hemicellulose during the pre-treatment process. Additionally, results showed a decrease in crystallinity and a change in surface morphology after the pre-treatment using all the seven solvent systems (MHS solvents). The use of ZnCl2.4H2O/ Urea solvent displayed 100% recovery of cellulose, 42% recovery of hemicellulose and 44% recovery of lignin from the corn-cob when compared to the performance of the other proposed solvent systems in this study.The National Research Foundation, South Africa and the University of the Witwatersrand, South Africa.http://www.tandfonline.com/loi/oaen20pm2021Chemical Engineerin

Kinetic study of activation and deactivation of adsorbed cellulase during enzymatic conversion of alkaline peroxide oxidation-pretreated corn cob to sugar

Please read abstract in the article.https://www.springer.com/journal/11814hj2022Chemical Engineerin

Experimental investigation of the effect of fatty acids configuration, chain length, branching and degree of unsaturation on biodiesel fuel properties obtained from lauric oils, high-oleic and high-linoleic vegetable oil biomass

Abstract A very good understanding of the structure, level, type and physical property relationships of fatty acids in plants oils and their methyl esters (FAMEs) is of utmost importance when selecting vegetable oils for a particular desired biodiesel quality that meets the operating condition requirements of the compression-ignition diesel engine and the climatic dictate of the environment under which the engine is operated. It is on this premise that the degree of influence of fatty acid configuration, chain length, branching and unsaturation on cold flow and critical properties of biodiesel was investigated. The critical properties studied include: saponification and cetane number, iodine value, higher heating values, density, flash point and kinematic viscosity. The feed stock consists of three groups of vegetable oil biomass. The group one is made up of highly saturated, lauric coconut and palm kernel oils while group two consists of high linoleic, soyabean and corn oil biomass with low percentage of mono-unsaturated and high percentage of poly-unsaturated fatty acid. High oleic olive and canola oil constituted the third group of biomass. The triglycerides in these oils were converted to methyl esters by alkali-catalyzed transesterification reaction under standard conditions. The fatty acid methyl esters (FAMEs) compositional analyses of these feed stocks was done by using Agilent, HP 6890 Gas Chromatograph equipped with Flame ionization detector and 6890 Auto Sampler that connects with a controller box (GC-FID). The various biodiesel cold flow behaviour and critical properties under investigation were evaluated by the American society for testing materials (ASTM D6751-07b) and the European union (EN 14214) standard procedures and techniques. Better cold flow behaviour was exhibited by biomass with higher degree of unsaturation, longer chain length, higher degree of branching and with cis configuration. While critical properties showed a lot of variations based on fatty acid profile