Formaldehyde in small quantities is commonly analyzed by spectrophotometric methods. One of the most-commonly used spectrophotometric techniques for this purpose is based on the reaction with chromotropic acid. Because of its simplicity, sensitivity, selectivity and its low cost, it is still widely used. Investigations for replacing the concentrated sulfuric acid with other acids or using more ...

The atmosphere is an inhomogeneous system of vapors, and liquid as well as solid particles. The nucleation process is an important source of particles, observed at most sites where particle measurements have been carried out. Sulfuric acid plays an important role in the first steps of particle formation, but a complete picture of process, after several years of research, is still unclear. Compu...

Neat chlorosulfonic acid reacts with anhydrous sodium tungstate to give tungstate sulfuric acid (TSA), a new dibasic inorganic solid acid in which two sulfuric acid molecules connect to a tungstate moiety via a covalent bond. A variety of oximes were oxidized to their parent carbonyl compounds under mild conditions with excellent yields in short times by a heterogeneous wet TSA/KMnO4 in dichlor...

Treatment of a sulfide with catalytic amount 1,3-diketone in the presence silica sulfuric acid as co-catalyst and hydrogen peroxide (50% aq) stoichiometric oxidant leads to corresponding sulfoxide product. The reaction is effective for diaryl, aryl-alkyl dialkyl sulfides tolerant oxidisable sensitive functional groups. Investigations have shown that tris-peroxide 2, formed on pentane-2,4-dione ...

Indonesia has very abundant reserves of silica, but progressive studies on the deposition this material are few, resulting in limited applications silica. This work refers to purification silica from quartz sand originated Sukabumi, obtain high-purity which can be applied as important raw materials for special purposes. The aim our research is improve low-grade by removing impurities, especiall...

in the recent years, rapid growth of the world’s population and overutilization of fresh water resources have caused fresh water shortage crisis in the world. in spite of the agricultural activities in the northern beaches of iran and also severe decrease of the ground water level, it still has not taken any effective measures to desalinate caspian sea water in large scale. in this research, de...

In this paper we develop a policy model for pollution control investment and operational decisions in the copper industry. The system consists of (i) a nonlinear integer model to optimize smelter operations, including the investment decisions relating to smelting capacity and pollution control plants that complies with environmental regulations, and (ii) a network flow model to describe the eco...

The self-assembly and sol-gel polymerisation of novel alkoxysilane-functionalized polymethylsiloxanes provide versatile access to nano-assembled containers, silica-based micro- and nano-architectures and dispersed mixed metal oxide hybrid materials.

In order to improve the erosion capacity of a supercritical carbon dioxide (SC-CO2) jet, the influence of a nano-silica additive on the rock erosion characteristics was experimentally investigated. By impinging the SC-CO2 jets with nano-silica mass fractions of 0 wt % (pure SC-CO2 jet), 3 wt %, 6 wt %, 9 wt %, 12 wt %, 15 wt %, and 18 wt % on specimens of red sandstone, the erosion volumes unde...

The effect of specimen aging on the recovery of mercury from urine samples was investigated. It was found that in some aged specimens the addition of concentrated sulfuric acid to the urine without cooling resulted in a large loss of mercury. This phenomenon is presumed to be due to enhanced volatility of the mercury caused by bacterial action. This loss can be avoided by adding a suitable pres...