Adsorption Characteristics of Combined Sulfhydryl Collector on Chalcopyrite and Arsenopyrite in Flotation of Complex Gold Ores

The paper presents the results of experimental study of the adsorption properties of the combined sulfhydril collecting reagent –a mixed solution of sodium diethyl-dithiocarbamate (DEDTC) and oxypropyl diethyl-dithiocarbamate ester (OPDTC) towardschalcopyrite and arsenopyrite with a view to its application as a selective collector of Au-containing sulfide minerals in flotationof complex refractory ores. Combined diethyl-dithiocarbamate solution (DEDTCc) incorporated a fixed content of anionic andnon-ionic components (DEDTC:OPDTC = 1:1) and occurred variable hydrophobic effect on the surface of the basic gold-bearingsulfide minerals – chalcopyrite and arsenopyrite.The mechanism of adsorption of the components of combined collector on the surface of chalcopyrite and arsenopyrite was identifiedto form characteristic molecular shape of adsorbed collector convex neoplasms and sinter chemically adsorbed film of thereactant, which is firmly anchored on the surface. The newly formed phase of the adsorbed reagent did not dissolve in water at asubsequent washing. In this case, the phase of nonionic ester OPDTC was partially removed by water and the residual adsorbeddroplets changed their shape and became flatter. By X-ray microanalysis C and O bands relating to the structure of the combinedDEDTCc were identified on the surface of arsenopyrite and chalcopyrite. The original technic for analyzing the liner dimension ofsurface images with an application of scanning laser microscopy and the software of the Analyzer was developed and the authorssucceeded to provide a quantitative evaluation of the adsorption of DEDTCc on the surface of chalcopyrite and arsenopyrite.

Mixed esters of xanthogenic acids containing carbonyl, dithiocarbamine and thiocyane group and their research as additives improving tribological characteristics

On the basis of environmentally friendly raw materials of glycerol, by its interaction with monochloroacetic acid, 1,2,3-(trichloroacetyl)triglyceride was synthesized, which is used for further syntheses of xanthogenic acid derivatives containing a number of functional groups  dithiocarbamic, thiocyanic. The reaction of 1,2,3-(trichloroacetyl) triglyceride with potassium alkylxanthate in a ratio of 1:1 and 1:2 gave 1-butylxanthogenatoacetoxy-2,3-(dichloroacetoxy) propane and 1,3-di(alkylxanthogenatoacetoxy)-2-chloroacetoxypropane. Mixed esters of xanthogenic acid containing dithiocarbamic and thiocyanic groups were synthesized by the interaction of 1,2,3-(trichloroacetyl) triglyceride in the corresponding sequence, first with sodium diethyl dithiocarbamate, with potassium butylxanthate, as a result 1-butylxanthogenatoacetoxy-2-chloracetoxy-3-(diethyldithiocarbamatoacetoxy) propane. Sequential reaction of 1,2,3-(trichloroacetyl) triglyceride with potassium rhodanide with potassium butylxanthate gave 1-butylxanthogenatoacetoxy-2-chloroacetoxy-3-(thiocyanatoacetoxy)propane. The structure of the synthesized compounds has been proven by IR spectroscopy. The compounds have been tested as additives to improve the tribological characteristics of oils and have been shown to be effective.

One-pot synthesis of dumbbell shaped PbS–Te hybrids with promising photothermal properties

The development of multi-component photothermal agents has attracted increasing attention due to their potential applications in energy conversion, medical treatments, etc. Herein, a dumbbell shaped PbS–Te heterostructure was prepared via a one-pot microwave-assisted decomposition of lead dimethyl dithiocarbamate and tellurium diethyl dithiocarbamate. The as-obtained PbS–Te hybrids exhibit excellent photothermal stability and strong optical absorption over a broad wavelength range spanning from ultraviolet to near-infrared, where the photothermal conversion efficiency could reach as high as 12.1%. Such promising photothermal performance demonstrates the advantages of one-pot synthesis that results in more intimate contacts among individual components.

Anion Inhibition Studies of the β-Class Carbonic Anhydrase CAS3 from the Filamentous Ascomycete Sordaria macrospora

CAS3 is a newly cloned cytosolic β-class carbonic anhydrase (CA, EC 4.2.1.1) from the filamentous ascomycete Sordaria macrospora. This enzyme has a high catalytic activity for the physiological CO2 hydration reaction and herein, we report the inhibition profile of CAS3 with anions and small molecules. The most effective CAS3 anions/small molecule inhibitors were diethyl-dithiocarbamate, sulfamide, sulfamate, phenyl boronic and phenyl arsonic acids, with KIs in the range of 0.89 mM–97 µM. Anions such as iodide, the pseudohalides, bicarbonate, carbonate, nitrate, nitrite, hydrogensulfide, stannate, selenate, tellurate, tetraborate, perrhenate, perruthenate, selenocyanide and trithiocarbonate were low millimolar CAS3 inhibitors. The light halides, sulfate, hydrogensulfite, peroxydisulfate, diphosphate, divanadate, perchlorate, tetrafluoroborate, fluorosulfonate and iminodisulfonate did not significantly inhibit this enzyme. These data may be useful for developing antifungals based on CA inhibition, considering the fact that many of the inhibitors reported here may be used as lead molecules and, by incorporating the appropriate organic scaffolds, potent nanomolar inhibitors could be developed.

UV 185+254 nm photolysis of typical thiol collectors: decomposition efficiency, mineralization and formation of sulfur byproducts

The decomposition of toxic flotation reagents upon UV 185+254 nm irradiation was attractive due to operational simplicity and no dosage of oxidants. In this work, the degradation of typical thiol collectors (potassium ethyl xanthate (PEX), sodium diethyl dithiocarbamate (SDD), O -isopropyl- N -ethyl thionocarbamate (IET) and dianilino dithiophoshoric acid (DDA)) was investigated by UV 185+254 nm photolysis. The degradation efficiencies and mineralization extents of collectors were assessed. The formation of CS 2 and H 2 S byproducts was studied, and the mechanisms of collector degradation were proposed under UV 185+254 nm irradiation. The PEX, SDD and IET were decomposed with nearly 100% removal upon 75 min of UV 185+254 nm irradiation. The decomposition rate constants decreased in the order SDD > PEX > IET ≫ DDA, and the DDA was the refractory collector. After 120 min of UV 185+254 nm irradiation, 15−45% of carbon and 25−75% of sulfur of collectors were completely mineralized, and the mineralization extent decreased in the order PEX > SDD > IET > DDA. The percentage of gaseous sulfur (CS 2 and H 2 S) ranged from 0.48 to 4.85% for four collectors, showing the fraction of emitted sulfur byproducts was small. The aqueous CS 2 concentration increased in the first 10−20 min, and was decreased to a low level of 0.05–0.1 mg l −1 at 120 min. Two mechanisms, i.e. direct UV 254 nm photolysis and indirect oxidation with free radicals, were responsible for collector decomposition in the UV 185+254 nm photolysis.

Ozone and ozone/vacuum-UV degradation of diethyl dithiocarbamate collector: kinetics, mineralization, byproducts and pathways

The diethyl dithiocarbamate collector, a precursor of toxic N-nitrosamines, can be effectively degraded by the O3/VUV with satisfactory mineralization extents.