Use of sintering to immobilize toxic metals present in galvanic sludge into a stabile glass-ceramic structure

Galvanization process requires the use a large amount of water and produces wastewaters that are usually purified by conventional cost-effective procedure. This kind of treatment generates waste sludge which becomes a hazardous if is not properly stabilized. Hence, the aim of this paper is to investigate the characteristics of galvanic sludge through the inspection of its physicochemical parameters and consider stabilization of waste materials, including waste glass and aluminum slag by their conversion into an eco-designed material referred to as glass ceramics. The obtained products have been studied by X-ray diffraction (XRD). XRD analyses confirmed occurrence of chemical and phase transformations in treated galvanic sludge and binding of toxic metals (Al3+, Cr3+, Cu2+, Cd2+, Ni2+, Pb2+, Zn2+) into crystalline phases and very sTab. structure.Процес галванизације захтева велику количину технолошке воде што има за последицу стварање отпадних вода, које се из економских разлога пречишћавају конвенционалним системима. Овим третманом настаје отпадни муљ који, уколико се адекватно не стабилизује, представља опасан отпад. У том смислу, у раду је извршена карактеризација галванског муља анализом физичкохемијских параметара компонената, а затим стабилизација ових отпадних материја, укључујући отпадно стакло и алуминијумску шљаку, превођењем у еко-синтеровани материјал стаклокерамика. Добијени производ анализиран је рендгенском дифракционом анализом (XRD). На основу XRD спектра потврђене су хемијско-фазне трансформације третираног галванског муља и везивање токсичних метала (Al3+, Cr3+, Cu2+, Cd2+, Ni2+, Pb2+, Zn2+) у веома стабилну кристалну структуру

Synthesis and characterization of quercetin-conjugated gold nanoparticles

Gold nanoparticles and quercetin-conjugated gold nanoparticles complex were synthesized using trisodium citrate as reducing agent. Both kinds of nanoparticles were characterized using spectrophotometry, dynamic light scattering and zeta potential measurements. Comparison of the results confirmed successful synthesis of quercetin-conjugated gold nanoparticles complex.Physical chemistry 2018 : 14th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 2018

Toxicological analysis of the risk of lead exposure in metal processing

Purpose: To evaluate toxicological risks for workers who are exposed to lead in their work environment. Methods: Since it is an important indicator of toxicological risk, a statistical analysis of lead concentration and biological lead toxicity markers in blood and urine were performed for both exposed and control groups. Both experimental groups consisted of employees from "NISSAL" JSC factory. Analytical epidemiological method in the form of a retrospective cohort study was applied, and covered the period from 2001 to 2010. The concentration of lead, δ-aminolevulinic acid, and coproporphyrin in biological samples were determined by spectrophotometric methods. Results: The results showed a high positive correlation between lead concentrations in blood and urine and the length of exposure of the participants (p < 0.01). Also, increase of lead concentration in the biological material significantly increased δ-aminolevulinic acid (p < 0.01) and slightly increased the concentration of coproporphyrin, both of which are important indicators of toxicological risk. Conclusion: The control group of employees belonged to the normal risk category, while the exposed group belonged to a moderate risk category. Correlation between the monitored parameters is statistically significant at p < 0.01 and p < 0.05. Keywords: Lead, δ-Aminolevulinic acid, Coproporphyrin, Chronic exposure, Toxicity, Correlatio

Adsorption of Organophosphate Pesticide Dimethoate on Gold Nanospheres and Nanorods

Organophosphorus pesticide dimethoate was adsorbed onto gold nanospheres and nanorods in aqueous solution using batch technique. Adsorption of dimethoate onto gold nanoparticles was confirmed by UV-Vis spectrophotometry, TEM, AFM, and FTIR analysis. The adsorption of nanospheres resulted in aggregation which was not the case with nanorods. Nanoparticles adsorption features were characterized using Langmuir and Freundlich isotherm models. The Langmuir adsorption isotherm was found to have the best fit to the experimental data for both types of nanoparticles. Adsorption capacity detected for nanospheres is 456 mg/g and for nanorods is 57.1 mg/g. Also, nanoparticles were successfully used for dimethoate removal from spiked drinking water while nanospheres were shown to be more efficient than nanorods

Electrochemical properties and thermal stability of epoxy coatings electrodeposited on aluminium and modified aluminium surfaces

The corrosion behaviour of epoxy coatings electrodeposited on aluminium, as well as on electrochemically and chemically modified aluminium were investigated during exposure to 3 % NaCl. Electrochemical impedance spectroscopy (EIS) and thermogravimetric analysis (TGA) were used for the determination of the protective properties of epoxy coatings on aluminium, anodized aluminium, phosphatized and chromatized-phosphatized aluminium. The protective properties of epoxy coatings on anodized and chromatized-phosphatized aluminium are significantly improved with respect to the same epoxy coatings on aluminium and phosphatized aluminium: higher values of the pore resitance and charge-transfer resistance, lower values of the coating capacitance, double-layer capacitance and relative permittivity (from EIS) smaller amount of absorbed water inside the coating (From TGA). On the other hand, the lower values of the ipdt temperature indicate a lower thermal stability of the epoxy coatings on anodized and chromatized-phosphatized aluminium

Oxidation of diazinon and malathion by myeloperoxidase

The aim of the work was to investigate the in vitro oxidation of diazinon and malathion, organophosphorous pesticides (OPs) containing phosphorthioate group, catalyzed by enzyme myeloperoxidase (MPO). The oxidation was performed in the presence of hydrogen peroxide. The products were identified as oxon derivatives (phosphates), where the sulfur atom from thioate group was substituted by an oxygen atom. No hydrolysis products were detected after enzyme - induced oxidation. The oxidation efficiency was controlled using acethylcholinesterase (AChE) bioassay for determination of oxon derivatives concentration. The influence of OPs concentration, incubation time of OPs with MPO, as well as MPO concentration on the yield of oxo forms was investigated. Kinetic constants of MPO in oxidation of malathion and diazinon were estimated. The maximum concentration of oxo forms was achieved after 10 min incubation of OPs in 50 mM phosphate buffer (pH 6.0) with 100 nM MPO. (C) 2011 Elsevier Inc. All rights reserved

Clarification and filtration of the floculated partuicles suspension from a chemical treatment of waste oil-in-water emulsions from a non-ferrous metalworking plant

The effects of the coagulation/floculation conditions on clarification and filtration of the floculated particle suspension obtained by the chemical treatment of the waste oil-in-water emulsion (OWE) from a non-ferrous metalworking plant were studied. The treatment involved the addition of aluminum(III) sulfate and lime to the OWE. The main goal was to define the optimum conditions for clarification and filtration of the floculated particle suspension. The factors involved were amounts lime (i.e. pH) and filter aid added the OWE on clarification and filtration rates. At pH>10, the clarification rate was increased and the final volume of the concentrated suspension (sludge) was reduced, while filter aid affected negatively the clarification rate. The filtration rate was also increased when the coagulation was carried out at pH>10. The floculated particle suspension should be concentrated before filtration in order to decrease the filtration duration. The most efficient filter aid was Celite standard super-cel, its optimum initial concentration being found to be 2 g/dm3

Acetylcholinesterase Inhibitors: Pharmacology and Toxicology

Acetylcholinesterase is involved in the termination of impulse transmission by rapid hydrolysis of the neurotransmitter acetylcholine in numerous cholinergic pathways in the central and peripheral nervous systems. The enzyme inactivation, induced by various inhibitors, leads to acetylcholine accumulation, hyperstimulation of nicotinic and muscarinic receptors, and disrupted neurotransmission. Hence, acetylcholinesterase inhibitors, interacting with the enzyme as their primary target, are applied as relevant drugs and toxins. This review presents an overview of toxicology and pharmacology of reversible and irreversible acetylcholinesterase inactivating compounds. In the case of reversible inhibitors being commonly applied in neurodegenerative disorders treatment, special attention is paid to currently approved drugs (donepezil, rivastigmine and galantamine) in the pharmacotherapy of Alzheimers disease, and toxic carbamates used as pesticides. Subsequently, mechanism of irreversible acetylcholinesterase inhibition induced by organophosphorus compounds (insecticides and nerve agents), and their specific and nonspecific toxic effects are described, as well as irreversible inhibitors having pharmacological implementation. In addition, the pharmacological treatment of intoxication caused by organophosphates is presented, with emphasis on oxime reactivators of the inhibited enzyme activity administering as causal drugs after the poisoning. Besides, organophosphorus and carbamate insecticides can be detoxified in mammals through enzymatic hydrolysis before they reach targets in the nervous system. Carboxylesterases most effectively decompose carbamates, whereas the most successful route of organophosphates detoxification is their degradation by corresponding phosphotriesterases

The identification and quantification of bioactive compounds from the aqueous extract of comfrey root by UHPLC-DAD-HESI-MS method and its microbial activity

In this study the qualitative, quantitative and microbial determination of the aqueous extract of comfrey root was done. The qualitative and quantitative analyses were done by the UHPLC-DAD-HESI-MS method. As major bioactive compounds, allantoin, rosmarinic acid and ellagic acid were identified and their quantification was also done. The obtained results showed a high content of allantoin, ellagic acid and rosmarinic acid (8.91, 7.4 and 12.8%, respectively) which indicated that the comfrey root can be used as a source for the isolation of these three compounds. The results obtained by the determination of the antimicrobial activity showed that Escherichia coli ATCC8739 and Salmonela typhimirium ATCC6538 were most sensitive to the aqueous extract of comfrey root. The results showed that allantoin did not express the antimicrobial activity on all the investigated bacteria species, and based on this it can be concluded that allantoin is not responsible for the antimicrobial activity of the aqueous extract of comfrey root. [Projekat Ministrstva nauke Republike Srbije, br TR-34012

Investigation of reaction between quercetin and Au(III) in acidic media: mechanism and identification of reaction products

The aim of the present paper was to investigate the reaction of quercetin, the flavonol very often used as a dietary supplement, with [AuCl4](-) ions. The reaction was studied spectrophotometrically using the equimolar solutions in 1 : 1 water-methanol at pH similar to 2. The spectrophotometric data indicated the formation of the products with an absorption maximum at 295 nm in all cases, characteristic of the oxidized forms of quercetin. HPLC coupled with DAD and LC-MS analysis of the reaction products suggested that the oxidation of quercetin resulted in the generation of similar metabolites including quinone and various oxidized quercetin-solvent adducts. In addition, cyclic voltammetric measurements confirmed that under applied experimental conditions, the reduction of Au(III) to Au(0) took place. The reduction species in the reaction mixture were Au(III) ions, while Au(I) disproportionates back to Au(III) and Au(0). The newly generated Au(III) ions further oxidized 3'-4'-dihydroxy groups of quercetin adducts obtained after first 2e(-) oxidation, giving the final reaction products. Based on the identification of reaction products, the reaction mechanism for the oxidation of quercetin in the presence of Au(III) which involves two 2e(-) transfer processes was proposed