Removal of Cr(VI) using co-immobilized activated carbon and <Emphasis Type="Italic">Bacillus subtilis</Emphasis>: fixed-bed column study

Fixed-bed column studies were conducted to evaluate the potential of co-immobilized (activated carbon and Bacillus subtilis) (CI) beads for the removal of Cr(VI) from aqueous solution. The impact of various parameters such as initial Cr(VI) concentrations (100, 150, and 200 mg/L), flow rate (3, 9, and 15 mL/min), and bed depth (10, 15, and 20 cm) on Cr(VI) adsorption onto CI beads were investigated. The breakthrough time increased with a decrease in initial Cr(VI) concentration and flow rate, and an increase in bed height. The breakthrough data obtained for Cr(VI) removal was more adequately described by the Thomas model with high correlation coefficients (R ² = 0.982). The eluent, 0.1 M NaOH, provided high elution efficiencies (~90 %) in all the six cycles. Obtained results pointed out that CI beads could potentially be used for the removal of Cr(VI) from aqueous solution.     

Impact of oxygenated cottonseed biodiesel on combustion,performance and emission parameters in a direct injection CI engine

In the present study, biodiesel production from the crude cotton-seed oil (CSO) and its feasibility to be used as fuel in compression ignition engine was analysed. Single-stage transesterification at molar ratio of 8:1 on crude CSO yielded 94% of cottonseed biodiesel (CBD). Gas chromatogram/mass spectrometry analysis revealed the presence of 19.5% unsaturated and 80.5% saturated esters in cotton seed biodiesel. Taguchi approach identified the stable fuel blend with oxygenate concentration. Increased oxygen concentration up to 20% were also analysed to understand the variation. Higher peak in-cylinder pressure was observed in D80CBD20 fuel blend. Diesel–biodiesel blend with oxygenate significantly affected the ignition delay and also resulted in varied exhaust gas temperature. D80CBD20nB10 showed an increase in brake thermal efficiency, whereas D80CBD20 exhibited higher brake specific energy consumption at full load. Carbon monoxide, hydrocarbon and smoke emission was found to be high in diesel with higher oxides of nitrogen in D80CBD20nB10. This experimental investigation finally revealed that, D80CBD20nB10 improved the combustion and performance characteristics with minimal emissions.

Abbreviations ASTM: American Society for Testing and Materials; BP: brake power; BSEC: brake specific energy consumption; BTE: brake thermal efficiency; CBD: cottonseed biodiesel; CI: compression ignition; CO: carbon monoxide; CO₂: carbon dioxide; CSO: cottonseed oil; DEE: diethyl ether; DOE: design of experiments; EGT: exhaust gas temperature; FTIR: Fourier transform infrared spectrometry; GC/MS: gas chromatogram/mass spectrometry; HC: hydrocarbon; HRR: heat release rate; HSDI: high speed direct injection; IDI: indirect injection; KOH: potassium hydroxide; MFB: mass fraction burned; NaOH: sodium hydroxide; NMR: nuclear magnetic resonance; N₂O: nitrous oxide; NO: nitric oxide; NO₂: nitrogen dioxide; NO _x : oxides of nitrogen; ROHR: rate of heat release; ROPR: rate of pressure rise; SOC: start of combustion; aTDC: after top dead centre; bTDC: before top dead centre     

Biosorption of chromium(VI) using Bacillus subtilis SS-1 isolated from soil samples of electroplating industry

Soils around the electroplating industry are often polluted with metals. The aim of the study was to assess Cr(VI) adsorption potential of chromium-resistant bacteria isolated from soil samples collected in and around electroplating industry, Coimbatore, India. A total of six morphologically different chromium-resistant bacteria were isolated from the soil samples and assayed for resistance to Cr(VI). Isolate designated SS-1 exhibited maximum resistance to Cr(VI) (600 mg/l) and subsequently identified as Bacillus subtilis based on the morphology, phenotypic characters, and partial 16S rDNA sequences. Batch experiments were carried out as a function of time, initial Cr(VI) concentration (100 mg/l), pH (2), and biosorbent dose (0.1 g/l). The maximum percentage of Cr(VI) removal was found to be 98.7 %. The experimental data showed a better fit with Langmuir model over Freundlich model throughout the range of initial concentrations. The kinetic models were examined with pseudo-first-order and pseudo-second-order kinetics. Fourier transform infrared spectroscopy studies confirmed the involvement of carboxyl and amide groups in Cr(VI) adsorption. Scanning electron microscopic studies revealed that nature of the bioadsorbent was altered after Cr(VI) adsorption. The results revealed that Cr(VI) was considerably adsorbed onto bacterial biomass, and it could be an economical method for the removal of Cr(VI) from aqueous solution.     

Assessment of waste plastic oil blends on performance,combustion and emission parameters in direct injection compression ignition engine

The present experimental investigation deals with the transformation of waste plastic into oil in a pyrolysis reactor. A single feed at a rate of 8?kg yielded 675?ml of pyrolytic oil. The physiochemical properties of plastic oil (PO) were found to be within American Society for Testing and Material standards with higher kinematic viscosity and carbon residue. The GC-MS and Fourier Transform Infrared Analysis studies revealed the presence of 14 different compounds in PO. Straight diesel–PO blending was carried out at 15% and 30% in volume ratio. At full-load condition, in-cylinder pressure, rate of pressure rise, rate of heat release and peak pressure were higher for PO30% than straight diesel. The brake thermal efficiency for PO blends was found to be slightly higher than straight diesel with a significant increase in brake-specific fuel consumption. Unburned hydrocarbon (UBHC), CO NO _x and smoke emission showed significant variation with PO blends. The physiochemical properties of PO blends significantly affect the engine performance.     

V2O5/RGO/Pt nanocomposite on oxytetracycline degradation and pharmaceutical effluent detoxification

The cover image is based on the Research Article V₂O₅/RGO/Pt nanocomposite on oxytetracycline degradation and pharmaceutical effluent detoxification by Mohan, H et al., DOI: 10.1002/jctb.6238 .

     

Monascus pigment production by solid-state fermentation with corn cob substrate

Natural pigments are an important alternative to potentially harmful synthetic dyes. We investigated the feasibility of corn cob powder as a substrate for production of pigments by Monascus purpureus KACC 42430 in solid-state fermentation. A pigment yield of 25.42 OD Units/gram of dry fermented substrate was achieved with corn cob powder and optimized process parameters, including 60% (w/w) initial moisture content, incubation at 30°C, inoculation with 4 mL of spores/gram of dry substrate, and an incubation period of 7 days. Pigment yield using corn cobs greatly exceeded those of most other agricultural waste substrates. The pigments were stable at acidic pH, high temperatures, and in salt solutions; all important considerations for industrial applications. Our results indicate the viability of corn cob substrate in combination with M. purpureus for industrial applications.     

Effect of fermentation on antioxidant,antimicrobial, anti-inflammatory,and anti-Helicobacter pylori adhesion activity of Ulmus davidiana var. japonica root bark

Food Science and Biotechnology - The limited yield of Ulmus davidiana var. japonica root bark (URB) extract is considered an economic loss to the food industry. Improving extraction yield and...     

Application of remote sensing and GIS for the demarcation of groundwater potential zones of a river basin in Kerala,southwest coast of India

An integrated hydrogeological investigation has been made to delineate the groundwater‐potential zones of the Muvattupuzha river basin, Kerala, along the southwest coast of India. The basin is characterized by charnockites and gneisses of Archean age covering more than 80% of the area and the remaining by Pleistocene laterites and Miocene formation. The basin receives high rainfall, measuring 3100 mm/year. However, acute water shortage occurs during the premonsoon season and hence, a number of dug wells are made to tap the groundwater. Seasonal rainfall during NE and SW monsoons is the major source of groundwater recharge. Further, hydrogeomorphology, geology, fracture systems and the slope of the terrain also play a significant role on the movement and behaviour of the groundwater of this basin. The integration of conventional and remote sensing data has been made through geographic information system (GIS) and it is found that about 50% of the area can be identified as very good or good potential zones, whereas the remaining area falls under moderate and poor categories. Most of the Muvattupuzha sub‐basin and the western part of the Kothamangalam and Kaliyar sub‐basins are classified as good groundwater‐potential zones, although the eastern upstream part of the basin has poor groundwater potential.     

Spectrometric analysis of algal biodiesel as a fuel derived through base-catalysed transesterification

The present experimental investigation focuses on production of biodiesel from marine macro algae Stoechospermum marginatum, a brown seaweed. S. marginatum was collected from the intertidal zone of coastal Tamil Nadu. Processed macro algae were subjected to lipid extraction through maceration and soxhlet methods. A single-stage transesterification process with methanol and NaOH was employed to synthesise biodiesel from crude algal oil. Characterisation of algal biodiesel (ABD) was carried out through analysis of gas chromatography mass spectrometry (GC-MS), Fourier transform infrared (FTIR) spectrometry and nuclear magnetic resonance (NMR) studies. GC-MS analysis revealed the presence of 14 different fatty acid methyl esters in ABD by their fragmentation patterns and retention time. The NMR and FTIR spectroscopy analysis confirmed the GC-MS data. The physiochemical properties of ABD were also determined through American Standards for Testing Materials methods and found to be within limits.

Abbreviations ABD: algal biodiesel; AO: algal oil; ASTM: American Society for Testing and Material; CO: carbon monoxide; CO₂: carbon di oxide; D: mineral diesel; FAME: fatty acid methyl ester; FFA: free fatty acids; FTIR: Fourier transform infrared spectroscopy; GC-MS: gas chromatography mass spectroscopy; HC: hydrocarbon; JBD: jatropha biodiesel; NMR: nuclear magnetic resonance; NO _x : oxides of nitrogen; PBD: palm oil biodiesel