Electrochemical destruction of thiourea dioxide in an undivided parallel plate electrodes batch reactor

The paper presents the results of a study on the electrochemical destruction of pollutants present in a spent reducing bath of a textile factory. The investigations comprised the electro-oxidation of thiourea dioxide (TUD) (the main component of the reducing bath), sulphites and urea, which are formed during oxidation of TUD. The study performed in an undivided cell parallel plate electrodes reactor, using eight different anode materials under various hydrodynamic conditions, proved that electro-oxidation can be successfully applied for treatment of spent reducing baths. The best results of TUD and SO₃²⁻ electro-oxidation were obtained with a Ti/Pt electrode, which showed electrocatalytic effect for both the compounds, indicating a possibility of their direct electro-oxidation on the anode. Destruction of TUD and SO₃²⁻ proceeded also via indirect electro-oxidation, mediated by chlorine evolved on the anode. The process kinetics was mass transport controlled till Re=5000. No electrocatalytic effects were observed for urea with any of the tested anode materials. The elimination of urea resulted to proceed only by indirect electro-oxidation, mediated by chlorine. For elimination of urea a Ti/Pt–Ir electrode proved to be the best anode, probably due to its high efficiency in electro-oxidation of chlorides into chlorine.     

低品位含金硫精矿硫脲法浸金试验研究

试验研究结果表明,该低品位含金硫精矿用硫脲法浸金在技术上是可行的。当试样磨至-0.044mm90%,经稀硫酸预浸后进行硫脲浸出,硫脲用量为5g/t、浸出时间为6h时,金的浸出率达81.09%。     

Spectral response of CdS/CdTe solar cells obtained with different S/Cd ratios for the CdS chemical bath

In this work, the influence of the variation of chemical bath thiourea concentration in the solution for depositing CdS layers upon the spectral response of chemical bath deposition (CBD)-CdS/CdTe solar cells is studied. Although changes in the short and long wavelength range for the spectral response of the cells were observed in dependence of the thiourea concentration, no significant changes were observed in the diffusion length of minority carriers in the CdTe layer, as determined from the constant photocurrent method, when the thiourea concentration is increased in the CdS deposition solution.     

N-(Diethylaminothiocarbonyl)ferrocenecarbimidoyl chloride, a versatile reagent

N, N-Diethiyl-N′-ferrocenoylthiourea reacts with thiophosgene to form N- (diethylaminothiocarbonyl) ferrocenecarbimidoyl chloride, which yields N-(diethylaminothiocarbonyl)-N′-(aryl/alkyl)ferrocenecarbamidines when reacted with primary amines via nucleophilic substitution. The reaction of bis(N,N-diethyl-N′-ferrocenoylthioureato)nickel(II) with phosgene gives 2,6-bis(diethylamino)-4-ferrocenium-1,3,5-thiadiazinium-tetrachloroniccolat(II). The X-ray structure determination of N-(diethylaminothiocarbonyl)benzimidoyl chloride is presented.     

硫脲对氮肥增产效益的影响

在本试验条件下,硫脲对氮肥有明显的增产效益,可做为氮肥的增效剂。在水田中硫脲最佳施用量27.7kghm-2,1kg硫脲可增加水稻产量25.7kg,可使水稻增产9.0%,与氮肥的比例0.2∶1,可做为水稻生长发育及产量形成的安全用量。在玉米田中硫脲最佳施用量39.9kghm-2,1kg硫脲可提高玉米产量22.2kg,增产幅度10.2%,与氮肥的比例0.19∶1,可做为玉米生长发育及产量形成的安全用量。     

Inhibition of Steel Corrosion in Nitric Acid by Sulfur Containing Compounds

The inhibitive mechanism, thermodynamics, and adsorptive properties of thiobarbituric acid (TBA) and thiourea (TU) on the corrosion of mild steel in 0.5 M HNO₃ solution have been investigated using potentiodynamic, electrochemical impedance spectroscopy techniques, and quantum chemical calculations. Both inhibitors showed good inhibition efficiency in nitric acid solution. TU was the most effective inhibitor and its inhibition efficiency increases with increasing concentration to attain 99% at 6 × 10^?3 mol · L^?1 at 30°C. Theoretical fitting of different isotherms, Langmuir, Flory–Huggins, Temkin, and the kinetic-thermodynamic models were tested to clarify the nature of inhibitors adsorption on mild steel surface. The obtained experimental data fitted all the applied adsorption isotherms except Langmuir. The thermodynamic activation parameters were determined to provide evidence of the inhibitory effect of TBA and TU. To determine the surface charge at the steel surface in nitric acid solution the potential of zero charge was measured using AC measurements at different potentials. Quantum chemical parameters were calculated and explained. The data clarified that the inhibition of steel in nitric acid by TU or TBA takes place through physicochemical adsorption mechanism.     

铜存在下络合滴定钯

考察了硫脲与Ｃｕ（Ⅱ）、Ｐｄ（Ⅱ）的ＥＤＴＡ络合物的反应。研究表明，一定条件下硫脲能迅速地与Ｐｄ（Ⅱ）结合释放出等量的ＥＤＴＡ，再与Ｃｕ（Ⅱ）反应，因而可在Ｃｕ（Ⅱ）存在下络合滴定钯。     

硫脲法提金浸取溶液中硫脲与Fe(Ⅱ)连续快速测定法

本文研究硫脲法提金浸取液中连续测定硫脲（TU）与Fe（Ⅱ）离子的适宜浓度范围、酸度影响及指示利使用量与校正等工作条件，建立了简便、快速、准确的连续测定方法，3～4min完成两个元素次的分析，相对标准偏差分虽低于0．1％与0．3％     

A quantitative measure of nitrifying bacterial growth

Nitrifying bacteria convert ammonia (NH3) to nitrate (NO3-) in a nitrification reaction. Methods to quantitatively separate the growth rate of these important bacterial populations from that of the dominant heterotrophic bacteria are important to our understanding of the nitrification process. The changing concentration of ammonia is often used as an indirect measure of nitrification but ammonification processes generate ammonia and confound this approach while heterotrophs remove nitrate via denitrification. Molecular probe methods can tell us what proportion of the microbial community is nitrifying bacteria but not their growth rate. The technique proposed here was able to quantify the growth rate of the nitrifying bacterial populations amidst complex ecological processes. The method incubates [methyl-3H] thymidine with water samples in the presence and absence of an inhibitor of nitrification-thiourea. The radioactively labeled DNA in the growing bacteria was extracted. The rate of incorporation of the label into the dividing bacterial DNA was used to determine bacterial growth rate. Total bacterial community growth rates in full-scale and pilot-scale fixed-film nitrifying reactors and an activated sludge reactor were 2.1 x 10(8), 4.1 x 10(8) and 0.4 x 10(8)cell ml(-1)d(-1), respectively; the growth rate of autotrophic-nitrifying bacteria was 0.7 x 10(8), 2.6 x 10(8) and 0.01 x 10(8)cell ml(-1)d(-1), respectively. Autotrophic-nitrifying bacteria contributed 30% and 60% of the total bacterial community growth rate in the nitrifying reactors whereas only 2% was observed in the activated sludge reactor that was not designed to nitrify. The rates of ammonia loss from the nitrifying reactors corresponded to the rate of growth of the nitrifying bacteria. This method has the potential to more often identify factors that enhance or limit nitrifying processes in both engineered and natural aquatic environments.     

在磷酸中缓蚀剂KA-01和硫脲对A3钢的缓蚀性能

缓蚀剂 Ｋ Ａ０１ 是室内合成的一种有机缓蚀剂。通过静态腐蚀检测和电化学测量对缓蚀剂 Ｋ Ａ０１ 和硫脲及其复配物在１５ ％ 和２８ ％ 磷酸中对 Ａ３ 钢的缓蚀性能进行了评价,评价结果表明 Ｋ Ａ０１ 和硫脲在３０ ℃和９０ ℃的１５ ％ 和２８ ％ 磷酸中单独使用时具有较好的缓蚀作用,而二者复配使用时缓蚀效果明显增加;在９０ ℃的１５ ％ 和２８ ％ 磷酸中加入１ ．８ ％ Ｋ Ａ０１ 和０ ．２ ％ 硫脲时 Ａ３ 钢的腐蚀速度低于１ ｇ／ ｍ２·ｈ ,缓蚀率高达９９ ．８ ％ 以上;电化学测量结果表明 Ｋ Ａ０１ 和硫脲是以阴极控制为主的缓蚀剂,而二者的复配物则表现出阴阳极混合控制的特征。