Obtaining Nickel Concentrates from Sludge Produced in the Process of Electrochemical Metal Surface Treatment

The article presents the possibility of recovering nickel from waste produced as a result of wastewater neutralization during the electrochemical surface treatment of metals. Leaching the sludge with concentrated hydrochloric acid enabled the metals contained in the sludge from precipitate to the solution with the efficiency of 74.4% (Se) to 100% (Zn). The content of elements was determined using the ICP-OES method. The next step was the precipitation of metals from the obtained solution using various reagents. The precipitating reagents used were 0.5 M sodium hydroxide solution, 0.5 M sodium sulphide solution and 1% dimethylglyoxime solution. Selective precipitation made it possible to obtain nickel concentrates with the content of nickel ranging from 15.3 to 98.2% for the first two methods, whereas in the case of the third method based on a dimethylglyoxime solution, the obtained nickel concentrate purity was 94.3%. The process of leaching nickel-dimethylglyoxime complex (Ni-DMG) with sulphuric acid and crystallization enabled obtaining 99.4% purity nickel sulphate, which can be reused in the nickel plating of selected metals. The research shows that waste generated in the process of neutralization of wastewater from electroplating plants is a potentially important source of recycled nickel concentrates.

Nanostructured nickel sulphate: properties and applications in marmalade production

The paper presents the data on the use of nanostructured nickel sulfate in the production of marmalade as a functional food product for prophylactic purposes. The nanoparticle tracking analysis (NTA method) was used to determine the size of nanostructured nickel sulfate. In this case, the smallest size (25.7 nm) is formed only in gellan gum with a core:shell ratio of 1:1. When the core:shell ratio in gellan gum is 1:3, the average size of nanocapsules is 49.9 nm. This result can be explained by the tighter packing of cobalt sulfate in the capsule. In sodium alginate, the average nanocapsule size is already 191 nm. The polydispersity index in all studied shells and at different core:shell ratios are practically equal and amounts to 0.84–1.09, which corresponds to a spherical shape.

Growth Kinetics of the (110) Faces of Complex Potassium Cobalt–Nickel Sulphate K2CoxNi1−x(SO4)2·6H2O Crystals

The normal growth rate, the steepness of polygonized growth hillocks and the velocity of step movement on the (110) faces of potassium cobalt–nickel sulphate crystals in aqueous solutions with cobalt to nickel ratios of 1:1 and 1:2 were investigated as a function of supersaturation by the geometry of growth hillocks using laser interferometry. It was found that the morphologies of growth hillocks on the (110) faces of the crystals grown from 1:1 and 1:2 solutions are similar and that the growth hillocks are formed by multiple screw dislocation sources. The experimental data on the growth kinetics of the (110) faces of the crystals were analyzed by using the Burton–Cabrera–Frank theory. It was found that (1) there is a critical supersaturation for the growth of the (110) faces, and the value of this supersaturation in the 1:2 solution is higher than that in the 1:1 solution, and (2) the kinetic coefficient of the step movement in the sectors of growth hillocks is highly anisotropic, and the values of this coefficient are larger in 1:2 solution than in 1:1 solution. These results are discussed in the presented work.

Analysis of Prevalence and Risk Factors of Contact Sensitization with respect to the Occupational Profiles in a Greek Patient Cohort: A Retrospective Analysis of a Greek Referral Centre and Future Perspectives

Contact dermatitis is a frequent skin disorder related to environmental and occupational etiological factors, which could potentially affect all age groups, as well as both genders. The current study is aimed at exploring the patterns of contact sensitization with respect to the population’s occupational patterns in Greece. A retrospective analysis was performed in a cohort of 1978 patients from 2014 to 2016. Patients were divided into two categories; blue collars (BlC) and white collars (WhC), as well as detailed occupation was considered. Separation was performed on the basis of their profession, i.e., labor workers and handicraftsmen were sorted to the BlC group, while office employees were sorted to the WhC group. The common allergen in all occupational subgroups was nickel sulphate. The three most prevalent allergens in both BlC and WhC were nickel sulphate 5%, fragrance mix (I) 8%, and Balsam of Peru 25%. WhC males were uniquely sensitized to colophony 20% and formaldehyde 2%, and WhC females were uniquely sensitized to 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT) and neomycin sulphate 20%. Sensitization to allergens manifested occupation-specific patterns. Allergic contact dermatitis surveillance is of great importance towards the clinical and systematic understanding of the disease, especially with respect to the patient’s occupational profile.

Study of Common Allergens in Patients with Allergic Contact Dermatitis: A Hospital Based Study

Allergic contact dermatitis (ACD) is one of the most common diseases presenting to the Dermatology department. The one and only method of preventing as well as treating this disease is avoidance of the allergen causing it. The identification of the allergen causing the ACD is possible by performing patch testing. The purpose of this study was to identify common allergens among patients with ACD using Indian standard series (ISS) of patch test. Clinically suspected cases of ACD were included in the hospital based cross-sectional study from January to December 2017. These cases underwent patch testing with the ISS. The study assessed the following variables: sex, age, occupation, site and positive patch test results. There were a total of 58 patients among which, 36.2% were males and 63.8% were females with a mean age of 32.36±12.51 years. Positive patch test reactions were seen in 63.0% of patients. The most common allergens were nickel sulphate (51.4%), fragrance mix (37.8%), potassium dichromate (8.1%), colophony (8.1%) and black rubber mix (8.1%). Among male, most common allergens were fragrance mix (57.1%), nickel sulphate (28.6%) and potassium dichromate (21.4%) while in female, most common allergens were nickel sulphate (65.2%) and fragrance mix (26.1%). In our study, majority of the allergens were positive. Hence, the ISS used in the study might be suitable in the context of Nepalese population. However, further similar studies on large number of patients with multiple allergens are required to determine the exact number of contact allergens prevalent in our population.

The Effect of Atopy in the Prevalence of Contact Sensitization: The Experience of a Greek Referral Center

Contact dermatitis is a well-known skin condition, which is related to stimuli and environmental exposure to chemicals, affecting all ages as well as both genders. In the present work, we attempt to investigate the patterns of contact sensitization, with respect to the personal history of atopy (AT), in Greece in a large number of allergens, using patch testing. The retrospective analysis included clinical routine data of 1978 patients collected from 2014 to 2016 in the Laboratory of Patch Testing, National Referral Centre of Occupational Dermatoses. Sensitization, in all cases, was tested with 28 allergens of the European baseline series as adjusted to our local circumstances and clinical experience. A total population of 1978 patients was evaluated, with a male-to-female ratio of 0.45 (1359 females/619 males). From our patient cohort, 693 (35%) patients were evaluated with a history of atopy, while 1285 (65%) were nonatopic. The five most prevalent allergens in the total population without AT were nickel sulphate 5% (15.47%), fragrance mix (I) 8% (9.10%), balsam of Peru (6.47%), cobalt chloride 1% (4.70%), and thiomersal 0.1% (4.10%). Respectively, in the total population with AT, the five most prevalent allergens were nickel sulphate 5% (10.36%), fragrance mix (I) 8% (5.11%), balsam of Peru (3.29%), thiomersal 0.1% (3.03%), and cobalt chloride 1% (2.78%). Contact dermatitis surveillance is of great importance towards the clinical and systematic understanding of the disease. Further studies should be directed towards that end, in order to facilitate more effective health policies.

Proses elektroplating nikel dengan variasi jarak anoda katoda dan tegangan listrik pada baja ST-41

Electroplating process is a coating process where the deposition of a thin metal coating occurs on a coated surface using direct current and constant voltage. The process of finishing metal products uses Nickel as a coating that serves to improve the properties of the metal so that it resists corrosion and attach importance to the appearance of the metal surface. The metal coating process is carried out by electroplating technique with Nickel which occurs as an anode, and electrolyte uses in this process contained Nickel Sulphate. This study aims to determine the effect of distance variations and electrical pressure on layer thickness and adhesive strength. Anode Material coated with ST-41 Steel Plate with dimensions of 70 x 25 x 20 mm. While the cathode uses nickel (Ni) with dimensions of 10 x 20 x 20 mm. Cathode distance variations with anodes 5, 10, and 15 cm and electrical voltage variations of 3.5 Volts, 5 Volts, and 7.5 Volts. Bath time of 40 minutes and adhesion testing using the Posi Test AT-M Adhesion Tester. The results obtained from this study are the distance of the cathode with the best anode found at a distance of 5 cm and a voltage of 7.5 volts with a thickness of 0.0160 mm. Then the best voltage is at 7.5 Volts with a sticky strength value of> 21.53 MPa.Keywords: Electroplating, Nickel, Anode, Cathode, ST-41 Steel.