M.G. Dastidar

Adsorptive removal of dye using biochar derived from residual algae after in-situ transesterification: Alternate use of waste of biodiesel industry

The primary aim of this present study was to utilize the residual biomass (DB) of Spirulina platensis algae, left after in-situ transesterification, for biochar preparation. This is a solid waste residue of biodiesel industry. The biochar (BC) prepared was examined for its capacity to adsorb congo red dye from the aqueous solution. The results were compared with other adsorbents used in the study such as commercial activated carbon (AC), original algae biomass (AB) and DB. The results of proximate analysis of BC showed the decrease in the percentage of volatile matter and an increase in fixed carbon content compared to DB. The physico-chemical properties of BC were studied using elemental analysis, SEM, FTIR and XRD techniques. The AC and BC adsorbents showed better performance in removing 85.4% and 82.6% of dye respectively from solution compared to AB (76.6%) and DB (78.1%). The effect of initial dye concentration, adsorbent dosage and pH of solution on the adsorption phenomena was studied by conducting the batch adsorption experiments. The highest specific uptake for biochar was observed at acidic pH of 2 with 0.2xa0g/100xa0ml of adsorbent dosage and 90xa0mg/l of initial concentration. The equilibrium adsorption data were fitted to three isotherms, namely Langmuir, Freundlich and Temkin. Freundlich model proved to show the best suited results with value of correlation coefficient of 99.12%. Thus, the application of DB for production of biochar as potential adsorbent supports sustainability of algae biodiesel.

Experimental Investigation on Adsorption Properties of Biochar Derived from Algae Biomass Residue of Biodiesel Production

The adsorption of methylene blue (MB) dye was investigated by utilizing biochar (BC) generated from residue (DB) of Spirulina platensis algae biomass (AB) left after simultaneous oil extraction and transesterification for biodiesel production. The motivation of the study was to reduce the overall downstream processing costs of biodiesel which could help in strengthening its sustainability economically. The experiments for batch adsorption studies were performed to examine the adsorption rate of MB dye from aqueous solution using adsorbents such as BC, AC (commercially available activated carbon), DB and AB as a function of initial dye concentration, adsorbent dosage and pH of the solution. The better adsorption was observed in the case of AC and BC, i.e., 95.6% and 92.6% of dye removal, respectively, compared to other two absorbents, AB (85.2%) and DB (86.4%). The maximum removal of dye (92.6%) was obtained by BC at alkaline pH with adsorbent dosage of 0.2xa0g/100xa0mL and initial concentration of dye of 90xa0mg/L. The adsorption capacity, qo, of biochar was found out to be 57.80xa0mg/g. Comparing the results of all three isotherms, namely Langmuir, Freundlich and Temkin, the coefficient of determination for Freundlich model was found to be the highest, and thus, it was selected as the most suitable isotherm to describe the equilibrium mechanics of dye adsorption. The production of BC from DB highlights that the waste residue of biodiesel industry can be alternatively used as adsorbent, enhancing the sustainability of algae biodiesel in an environmentally friendly manner.

Experimental investigation on performance and emission characteristics of a compression ignition engine fueled with biodiesel from waste tallow

Tallow oil being one of the non-edible oils can be explored for biodiesel production; however, limited information is available in literature regarding the use of tallow biodiesel as an alternate form of energy. This study deals with systematic characterization of tallow biodiesel to find its suitability for diesel engines. The chemical nature and composition of tallow biodiesel as determined by NMR, FTIR and GC analyses are closely related to established biodiesel properties. In this investigation, tallow biodiesel blends (B10, B20 and B100) were used to study the performance and emission of compression ignition engine at different loads (20, 40, 60, 80 and 100%), and the results were then compared with baseline results of conventional base diesel. The fuel properties of biodiesel and its blends were also determined which were comparable with that of diesel. Brake thermal efficiency for biodiesel blends were in comparable range with that of base diesel. The average reduction in carbon monoxide, hydrocarbon and smoke emission for B100 blend of biodiesel was observed to be 16.04, 28.09 and 28.57%, respectively, compared to base diesel. However, there was an average increase in NOx emission (15.34%) for B100 blend compared to diesel. The overall results show that tallow biodiesel could be recommended as a diesel fuel alternate.