Complexes and clusters bridge the gap between molecular and macroscopic levels by linking individual gaseous molecules to newly formed nanoparticles but the driving forces and mechanism for the formation of complexes and clusters in the atmosphere are not well understood. We have performed ab initio and density functional quantum chemical calculations to elucidate the role of organic acids in t...

A selective pressurized liquid extraction procedure (SPLE) was developed for a fast determination of polychlorinated biphenyls in sediment. The final method was performed at 100 degrees C with heptane/dichloromethane (90:10, v/v) as extraction solvent for 2x5 min. Sulfuric acid impregnated silica was placed downstream of the sample in the extraction cell to remove interfering components. This s...

silica exists in rice husk, an agriculture waste, as a naturally occurring phase. in first step, acidic pre-treatment and calcination of the rice husk were performed to obtain nano-silica, in which various sizes of the nano-silica, totally with sizes under 80 nm, were achieved. second, to reduce nano-silica to elemental si and subsequently formation of the composite, mg used as the reducing age...

Two simple protocols for the synthesis of three-component condensation reaction of an aldehyde, β-ketoester and urea or thiourea to obtain the 3, 4-dihydropyrimidin-2(1H)-ones (thiones) using nano silica phosphoric acid are reported. Short reaction times, high yields, reusability of catalyst and easy workup are some advantages of these protocols.

Dicarboxylic organic acids have properties that differ from those of sulfuric acid during hydrolysis of lignocellulose. To investigate the effects of different acid catalysts on the hydrolysis and degradation of biomass compounds over a range of thermochemical pretreatments, maleic, oxalic and sulfuric acids were each used at the same combined severity factor (CSF) values during hydrolysis. Xyl...

This study investigated the relationship between solubility and chemical speciation of plant nutritional elements (K, Ca, Si) in wood ash treated with a dilute solution sulfuric acid or phosphoric acid. The diluted solutions were added to fly (FA) collected from power plant, untreated acid-treated FAs analyzed for their contents K, Si. crystalline phases identified using X-ray diffraction (XRD)...

Based on the first National Study of Coal Workers' Pneumoconiosis (CWP) and the U.S. Geological Survey database of coal quality, we show that the prevalence of CWP in seven coal mine regions correlates with levels of bioavailable iron (BAI) in the coals from that particular region (correlation coefficient r = 0.94, p < 0.0015). CWP prevalence is also correlated with contents of pyritic sulfur (...

Fuel ethanol can be produced from bamboo by concentrated sulfuric acid hydrolysis followed by continuous ethanol fermentation. To reduce the environmental impact of this process, treatment of the stillage, reuse of the sulfuric acid and reduction of the process water used were studied. The total organic carbon (TOC) concentration of stillage decreased from 29,688 to 269 mg/l by thermophilic met...

An efficient and green protocol for the synthesis of 2-arylsubstituted benzimidazoles via a condensation reaction of aromatic aldehydes and 1,2-phenylenediamine using nano-Fe3O4@SiO2-SO3H as a solid acid catalyst in ethanol under reflux conditions has been described. The reactions are completed in short times, and the corresponding benzimidaz...

This study addresses the feasibility of removing Cu and Ni from sludges of printed circuit board (PCB) plants by acidic extraction. Citric acid, acetic acid, hydrochloric acid, nitric acid, and sulfuric acid at various concentrations were experimentally examined to determine preferred conditions for removing Cu and Ni. Experimental results indicate that the removal ratios of Cu were 57% (citric...