In this study, the recovery of platinum and palladium from petroleum catalysts has been elaborated using a method consisting mainly of dissolving alumina substrate in sulfuric acid thereby concentrating the precious metals in the residue. The effect of dissolution temperature and time, concentration of sulfuric acid, and pulp density on the dissolution of alumina substrate was investigated syst...

The atmospheric effects of soot aerosols include interference with radiative transfer, visibility impairment, and alteration of cloud formation and are highly sensitive to the manner by which soot is internally mixed with other aerosol constituents. We present experimental studies to show that soot particles acquire a large mass fraction of sulfuric acid during atmospheric aging, considerably a...

Dental erosion, and specifically its symptoms, has long been studied in Japan as an occupational dental disease. However, in recent years, few studies have investigated the development of this disease or labor hygiene management aimed at its prevention. As a result, interest in dental erosion is comparatively low, even among dental professionals. Our investigation at a lead storage battery fact...

a new, convenient, efficient, and cost-effective one-pot synthesis of 1hphenanthro[9,10]imidazol-2-yl from phenanthraquinone and aldehydes, using sulfuric acidimmobilized on silica as catalyst is described. the present methodology offers severaladvantages such as excellent yields, simple procedure, shorter reaction times, the use ofinexpensive reagents, easy recovery and eco-friendly. in additi...

Cellulolytic enzymes consist of a catalytic domain, a linking peptide, and a binding domain. The paper describes research on carboxylic acids that have potential as catalytic domains for constructing organic macromolecules for use in cellulose hydrolysis that mimic the action of enzymes. The tested domains consist of the series of mono-, di-, and tricarboxylic acids with a range of pK(a)'s. Thi...

Mannich reaction was applied between 4-fluorobezaldehyde, selected acetophenone and several anilines, catalyzed by silica sulfuric acid for the synthesis of β-amino carbonyl derivatives. Reaction time and yield of the products depended on the nature of acetophenone and aniline subsituents. Using aliphatic amines instead of aromatic amines under same reaction conditions, afforded aldol condensat...

Spices play an important role in the chemoprevention and they can be a rich source of biologically active compounds such as triterpenes in the human diet. A method based on high performance thin-layer chromatography combined with densitometry for determination of ursolic and oleanolic acids in some common spices was elaborated. The prechromatographic derivatization with 1% of iodine solution wa...

The temperature-dependent hydrolysis and solubility of chitosan in sulfuric acid solutions offer the possibility for chitosan extraction from zygomycetes mycelia and separation from other cellular ingredients with high purity and high recovery. In this study, Rhizomucor pusillus biomass was initially extracted with 0.5 M NaOH at 120 °C for 20 min, leaving an alkali insoluble material (AIM) rich...