In this investigation, biodiesel was produced from Moringa oleifera oil through a transesterification process at operating conditions including a reaction temperature of 60 °C, catalyst concentration of 1% wt., reaction time of 2 h, stirring speed of 1000 rpm and methanol to oil ratio of 8.50:1. Biodiesel blends, B10 and B20, were tested in a compression ignition engine, and the performance and emission characteristics were analyzed and compared with high-speed diesel. The engine was operated at full load conditions with engine speeds varying from 1000 rpm to 2400 rpm. All the performance and exhaust pollutants results were collected and analyzed. It was found that MOB10 produced lower BP (7.44%), BSFC (7.51%), and CO2 (7.7%). The MOB10 also reduced smoke opacity (24%) and HC (10.27%). Compared to diesel, MOB10 also increased CO (2.5%) and NOx (9%) emissions.
Groundwater is the most important source of water supply in Beijing city. However, groundwater has undergone intensive total hardness pollution caused by water-rock interaction and by human activities. Analysis of monitoring data of 30 years shows that the high concentration of total hardness is relationship with carbonate mineral dissolution and cation exchange. But speciation calculations of two flow path using the hydrogeochemical modeling code PHREEQC indicated that the annual contribution of carbonate dissolution and cation exchange to concentration of Ca 2+ and Mg 2+ is less than 1 mg•L-1 , which was far less than that observed. The results illustrated that carbonate mineral dissolution and cation exchange in aquifers play a small role in the contribution of groundwater chemical evolution, and also imply other anthropogenic sources exist indirectly.
Activated carbons prepared from shea cake (CA-K) and cotton cake (CA-C) were investigated for removal of four dyes in aqueous solutions (0 -200 mg/L): Reactive Black 5 (RB5), Methylene blue (BM), Reactive Orange 16 (RO16) and Methyl Orange (MO) from water by adsorption. The activated carbons were prepared by chemical activation using phosphoric acid as activation agent. Chemical characteristics of these activated carbons was monitored by Bohem titration and the method of Lopez-Ramon et al. while surface areas of the samples were determined by nitrogen adsorption/desorption isotherm measurement. Activated carbons CA-K and CA-C have the following characteristics: BET surface and the pore volumes are respectively 1148 m 2 /g and 0.607 cm 3 /g for CA-K, 584 m 2 /g and 0.298 cm 3 /g for CA-C. The two activated carbons synthesized are microporous
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