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PubMed2000

Adsorption Equilibrium of Polyethylene Glycol in the Copper Electroplating Solution on Activated Carbon.

Polyethylene glycol (PEG) used as a brightening and stabilization agent at the concentration of 30 mg dm(-3) is a major organic additive in the copper electroplating solution. Activated carbon, Calgon Filtrasob 400, is used as the adsorbent to remove the PEG from the used electroplating solution in order to broaden the appeal of recycling it. The equilibrium of adsorption is attained within 14 days. The effect of the temperature on the amount of PEG adsorbed on the activated carbon is insignificant for the temperatures ranged from 288 to 313 K. The adsorption isotherm of PEG conforms to the Langmuir isotherm, q(e)=Q(L)K(L)C(e)/(1+K(L)C(e)), with a high correlation coefficient of 0.9979. The large values of the monolayer adsorption capacity, Q(L), of 303 mg g(-1) and the equilibrium constant, K(L), of 0.273 dm(3) mg(-1) show a great adsorption potential of PEG on the activated carbon. A high removal efficiency would be expected at such a low original concentration of PEG. From the results mentioned above, it is feasible to use activated carbon for removing PEG from the electroplating solution, thereby achieving the appeal of recycling. Copyright 2000 Academic Press.

Journal Article↗
PubMed1996

Disorganisation of quantal acetylcholine release by zinc at the Torpedo nerve-electroplate junction.

The effects of zinc (Zn2+) on quantal acetylcholine release at the Torpedo nerve-electroplate junction were analysed by using loose patch electrodes designed to record evoked and spontaneous electroplate currents in a delimited area (electrode diameter of 10-15 microm) of the synaptic region. Zn2+ reduced the amplitude, prolonged the synaptic delay and slowed down the rising phase of all-or-none electroplate currents (EPCs) generated in response to activation of Na+ channels in a preterminal nerve branch. In graded EPCs (generated in response to direct activation of terminal Ca2+ channels), Zn2+ caused a reduction of quantal content but no change in the quantal size or in the minimum synaptic delay. The rise time of graded EPCs was prolonged but their half-decay time was not affected. Miniature EPCs (MEPCs) in control preparations had a widely distributed amplitude distribution but a homogeneous and rapid time course. Conversely, MEPCs in Zn2+-treated tissue exhibited a homogeneous and small amplitude, but a prolonged and more variable time course. Zn2+ at 1 mM caused, by itself, a high occurrence of MEPCs under conditions (flat-edged electrodes) when MEPCs are normally very infrequent. It is concluded that Zn2+ can both activate and inhibit the release mechanism and Zn2+-induced quanta exhibit an abnormal time course. The activation of the release process by Zn2+ or by Ca2+ may result in the production of quanta with different kinetics.

Acetylcholine↗
PubMed2006

Efficiency of Penicillium chrysogenum PTCC 5037 in reducing low concentration of chromium hexavalent in a chromium electroplating plant wastewater.

The effectiveness of Penicillium chrysogenum was evaluated for reducing Cr(VI) from the wastewater of a chromium electroplating plant. Statistically-based experimental designs were applied to optimize the condition for reducing Cr(VI) to Cr(III). By applying Plackett-Burman factorial design and central composite design as the optimization step, attempts were made to identify optimal values of the three factors that bringing about maximum microorganism activity and therefore maximum hexavalent chromium(VI) bioreduction. It was found that each gram of P. chrysogenum of dry biomass condition could reduce 66 mg of Cr(VI) to Cr(III) in the wastewater of the chromium electroplating plant.

Biodegradation, Environmental↗
PubMed2005

Crab shell-based biosorption technology for the treatment of nickel-bearing electroplating industrial effluents.

This paper discusses the possible application of a biosorption system with acid-washed crab shells in a packed bed up-flow column for the removal of nickel from electroplating industrial effluents. Between two nickel-bearing effluents, effluent-1 is characterized by considerable amount of light metals along with trace amounts of lead and copper. Effluent-2 is characterized by relatively low conductivity, total dissolved solids and total hardness compared to effluent-1. Crab shells exhibited uptakes of 15.08 and 20.04 mg Ni/g from effluent-1 and effluent-2, respectively. The crab shell bed was regenerated using 0.01 M EDTA (pH 9.8, aq. NH3) and reused for seven sorption-desorption cycles. The EDTA elution provided elution efficiencies up to 99% in all the seven cycles. This, together with the data from regeneration efficiencies for seven cycles, provided evidence that the reusability of crab shell in the treatment of nickel-bearing electroplating industrial effluents is viable.

Adsorption↗
PubMed1996

The genotoxicity of iron and chromium in electroplating effluents.

Electroplating effluents were tested for their genotoxicity with the micronucleus test on newt larvae. The metallic content of the tested samples was responsible for the induction of micronuclei in red blood cells (RBC). Then, iron (Fe3+), chromium (Cr3+, Cr6+) and zinc (Zn2+) which were identified in these samples, were tested either separately or combined, at their concentrations in the electroplating effluents. Fe3+ induced a high level of micronuclei at 12.5 and 25 mg/l (nominal concentrations). Both soluble and non-soluble forms of iron were responsible for these genotoxic effects. At lower concentrations (0.6 and 4.5 mg/l) Fe3+ was not systematically genotoxic. Zinc could not be considered genotoxic on newt. Cr3+ gave negative responses, but exposure to Cr6+ (1 mg/l) could result in a significant number of micronucleated RBC in some cases. The most dramatic genotoxic effects were registered when Fe3+ and Cr6+ were combined. This study demonstrates that interactions between pollutants and the effects of non-soluble chemicals on aquatic vertebrates and invertebrates can no longer be neglected.

Animals↗
PubMed2001

Removal and recovery of heavy metals from electroplating wastewater by using Kyanite as an adsorbent.

Kyanite, a commercial mineral has been utilized as an adsorbent for the removal of heavy metals, such as Ni(II), Zn(II), Cr(VI) and Cu(II) from electroplating wastewater. The effect of contact time, pH, concentration, adsorbent doses, particle size of the adsorbent, salinity and hardness, both in natural and wastewater on the adsorption of Cu(II) have been studied in detail. The adsorption of metal ions seems to be an ion exchange process. The adsorbed metals ions from electroplating wastewater were recovered by batch as well as column operation using dilute HCl solution. The column operation was found to be more effective compared to batch process.

Adsorption↗
PubMed2004

Adsorption of Cr(VI) from aqueous and electroplating wastewater.

The aim of this work was to investigate the use of activated rice husk carbon prepared by thermal activation and activated alumina in the removal of Cr(VI) from aqueous solution and electroplating wastewater through column studies. The optimum solution pH was found to be 2 for activated rice husk carbon and 4 for activated alumina in the batch process. This was further applied to the aqueous solution to optimise the column bed height, diameter and flow rate of solute. These optimised conditions were applied to the electroplating wastewater. It was observed that activated rice husk is an efficient adsorbent and comparable to commercially available activated alumina. The percent Cr(VI) removal from wastewater was 73.3% with activated rice husk and 75.3% with activated alumina after 1 h continuous flow at the rate of 5 ml min(-1) from 7.5 cm bed height of adsorbent in a column having diameter 2.5 cm. A long contact time of the samples with adsorbents resulted in desorption of Cr(VI) from the adsorbent surfaces. However, the adsorption rate increased with the more available adsorbent surface sites when column bed height and diameter were greater. There was a decrease in Cr(VI) removal compared to aqueous sample due to the presence of other metal ions in the wastewater sample.

Adsorption↗
PubMed2001

Removal of lead ions by keramzite sand coated with electroplating sludge under dynamic conditions.

Column studies were performed to determine the effect of bed height, linear flow rate, adsorbent particle size and initial metal ion concentration on lead removal by keramzite sand coated with electroplating sludge. The Bed depth service time (BDST) model applied to the data at 2% breakthrough gave the best approximation to the experimental results compared with other investigated breakthrough points. The adsorption performance of the thermally modified coated keramzite columns could be well described by the Wolborska model up to 50% breakthrough point. The application of this model allowed determination of the kinetic coefficients of external mass transfer in the fixed bed and the time for protective action of the sorbent layers. The experimental results support the assumption that the external mass transfer of the solute through the hydrodynamic boundary layer is the rate-limiting step. It has been established that the keramzite sand coated with electroplating sludge (particle size 0.5-0.8 mm) can be successfully used for lead removal from dilute metal ion solutions at linear flow rate 4-6 cm/min and empty bed contact time > or = 3 min.

Adsorption↗
PubMed2004

Purification of electroplating wastewaters utilizing waste by-product ferrous sulfate and wood fly ash.

A new procedure for electroplating wastewater treatment using waste by-product (ferrous-sulfate) and waste (wood fly ash) is presented. Ferrous-sulfate was employed for Cr(VI) reduction whereas neutralization and heavy metal removal from electroplating wastewaters was performed using wood fly ash. Heavy metal removal efficiency varied from 97.5% for Cu to 99.973% for Zn. Satisfying results can be achieved already at the pH 8. The method is suitable for the purposes of wastewater treatment and disposal in compliance with environmental laws. Furthermore, it is technically simple, cost-efficient and requires less space compared to the classical methodology. According to the composition of its water extractable fraction remaining waste ash could be safely deposited on domestic waste repositories.

Chromium↗
PubMed2004

Dermal exposure to electroplating fluids and metalworking fluids in the UK.

This paper describes workplace dermal exposure measurements that were carried out by the Health and Safety Laboratory as part of the EU RISKOFDERM project. Exposure to metalworking fluids (MWFs) was measured at three sites on 25 subjects who were 'mechanically treating solid objects' as they loaded and supervised milling and boring machines and lathes. Thirty-one samples were obtained, of which 18 were exposures to neat mineral oils and 13 to water-oil mixes. All subjects wore Tyvek whole-body oversuits that were analysed in their entirety to extract the MWF. The geometric mean surface loading rate of the 31 oversuits was 62 micro g/cm(2)/h (GSD = 4.6) and of the seven pairs of sampling gloves (worn inside protective gloves) was 2900 micro g/cm(2)/h (GSD = 1.67). Exposure to electroplating fluids was measured at three sites on 27 subjects who were dipping objects into tanks of either chromic acid, nickel sulphate, copper sulphate, copper cyanide or zinc hydroxide. All subjects wore Tyvek whole-body oversuits that were surface scanned over their areas using a portable X-ray fluorescence spectrometer to detect all the metal atoms simultaneously. Contamination was assessed using the method of Dirichlet tessellation. The geometric mean surface loading rate of the 26 oversuits was 37 micro g/cm(2)/h (GSD = 3.5) and of the 25 pairs of sampling gloves (worn inside protective gloves) was 190 micro g/cm(2)/h (GSD = 2.75). Almost all of the electroplating samples were below the limit of quantification. More than one species of metal atoms was found on some of the samples afterwards, indicating cross-contamination from other baths during the sampling period.

Abdomen↗
PubMed1997

Health and safety behaviour and compliance in electroplating workshops.

Skin problems are reputedly common in electroplaters. To examine the steps taken by employers and employees to prevent or control skin problems, we visited six randomly selected electroplating establishments in Dorset and interviewed the employers and 50 of the employees using structured questionnaires. Several of the companies had not complied with the statutory requirements of the Control of Substances Hazardous to Health (COSHH) Regulations 1988, and deficiencies were evident in assessment, control and health surveillance. A third of the employees had current or recent work-related skin problems, typically dermatitis. Workers were generally ignorant about the hazards of materials handled. They knew about personal protective equipment, but did not always use it, or used gloveware that was deficient or contaminated. Only one in five employees adopted a rudimentary skin care programme; many were unaware of the provision for skin care. There is an urgent need for better training and more attention to skin care in electroplating workshops.

Adult↗
PubMed2003

Chromium (VI) induced oxidative damage to DNA: increase of urinary 8-hydroxydeoxyguanosine concentrations (8-OHdG) among electroplating workers.

AIMS: To investigate the concentration of urinary 8-hydroxydeoxyguanosine (8-OHdG) among electroplating workers in Taiwan. METHODS: Fifty workers were selected from five chromium (Cr) electroplating plants in central Taiwan. The 20 control subjects were office workers with no previous exposure to Cr. Urinary 8-OHdG concentrations were determined using high performance liquid chromatography with electrochemical detection. RESULTS: Urinary 8-OHdG concentrations among Cr workers (1149.5 pmol/kg/day) were higher than those in the control group (730.2 pmol/kg/day). There was a positive correlation between urinary 8-OHdG concentrations and urinary Cr concentration (r = 0.447, p < 0.01), and urinary 8-OHdG correlated positively with airborne Cr concentration (r = 0.285). Using multiple regression analysis, the factors that affected urinary 8-OHdG concentrations were alcohol, the common cold, and high urinary Cr concentration. There was a high correlation of urinary 8-OHdG with both smoking and drinking, but multiple regression analysis showed that smoking was not a significant factor. Age and gender were also non-significant factors. CONCLUSION: 8-OHdG, which is an indicator of oxidative DNA damage, was a sensitive biomarker for Cr exposure.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2004

Preparation of polyaniline coating on a stainless-steel wire using electroplating and its application to the determination of six aromatic amines using headspace solid-phase microextraction.

A novel polyaniline (PANI) coating was prepared on a stainless-steel wire for solid-phase microextraction by electroplating method. For better mechanical strength, the stainless-steel wire was used instead of the fused silica fiber. The electroplating method had advantages of ease of preparation and simple equipments. The PANI fiber was evaluated by analyzing six aromatic amines (aniline, N,N-dimethylaniline, m-methylaniline, 2,4-dimethylaniline, 2-chloroaniline, 3,4-dichloroaniline) in water. After the analytical procedure was optimized, the linearity was from 4.8 to 2.75 x 10(4) microg L(-1) and the detection limits was from 0.019 to 1.06 microg L(-1). Relative standard deviations were found to be 2.02-6.00%. Good recoveries were obtained when wastewater samples were analyzed.

Amines↗
PubMed2004

Electrochemical oxidation of polyethylene glycol in electroplating solution using paraffin composite copper hexacyanoferrate modified (PCCHM) anode.

Electrochemical oxidation of polyethylene glycol (PEG) in an acidic (pH 0.18 to 0.42) and high ionic strength electroplating solution was investigated. The electroplating solution is a major source of wastewater in the printing wiring board industry. A paraffin composite copper hexacyanoferrate modified (PCCHM) electrode was used as the anode and a bare graphite electrode was used as the cathode. The changes in PEG and total organic carbon (TOC) concentrations during the course of the reaction were monitored. The efficiency of the PCCHM anode was compared with bare graphite anode and it was found that the former showed significant electrocatalytic property for PEG and TOC removal. Chlorides present in the solution were found to contribute significantly in the overall organic removal process. Short chain organic compounds like acetic acid, oxalic acid, formic acid and ethylene glycol formed during electrolysis were identified by HPLC method. Anode surface area and applied current density were found to influence the electro-oxidation process, in which the former was found to be dominating. Investigations of the kinetics for the present electrochemical reaction suggested that the two stage first-order kinetic model provides a much better representation of the overall mechanism of the process if compared to the generalized kinetic model.

Carbon↗
PubMed2006

[Thermal analysis and the distribution rule of heavy metals during electroplating sludge combustion].

A representative hazardous waste containing heavy metal is electroplating sludge, Thermal characteristic and the distribution of different heavy metal elements (Pb, Cd, Cu, Zn, Ni and Mn) was studied. The results of experiment show that from thermal analysis, in the process of experiment of thermal gravity there are some peaks of weight loss as 100 degrees C, 150 degrees C and 600 degrees C among these peaks, the peaks of 100 degrees C and 150 degrees C is caused by that the volatile separated out and organic matter combusted and pyrolysed at the same time, the peak of 600 degrees C is produced by the carbonate decomposed. From EDS analysis, electroplating sludge is composed by these main elements which are O, S, Al, Ca, Cr and Fe, and other secondary elements such as Mg, Cu, Zn, P, Cl and C. In the process of temperature promoted, the quantity of nonmetal such as C and Cl is decreased, and the quantity of Cr, Fe, and Mg is steady within 900 degrees C. From the experiment of distribution rule, the quantity of Mn, Pb, Ni and Cu decreased in the process of combustion while the furnace temperature raised,among these heavy metal the quantity of Ni decrease most obviously,and on the contrary the quantity of Cd enrich obviously in this process.

Electroplating↗
PubMed1991

Microalgae as bioabsorbents for treating mixture of electroplating and sewage effluent.

The effectiveness of copper and nickel uptake by microalgae grown in the mixture of electroplating effluent and sewage was studied. The results showed that a high percentage of copper removal (68.1%-88.2%) was achieved by Chlorella pyrenoidosa (strain No. 26) reared in the mixture of 90% electroplating effluent and 10% raw sewage during the first 3 days despite the fact that cell growth was inhibited. Similar results were also obtained by using Chlorella HKBC-C3, another species collected from one of the heavy metal polluted sites in Hong Kong, isolated and cultured in the Biology Department. There was no significant difference (P greater than 0.05) in the removal of copper and nickel from the effluent between these 2 algal species. However, it was noted that removal of nickel from the mixture by the two species were comparatively lower (less than 20%) than the removal of copper (greater than 68%).

Absorption↗
PubMed1998

Toxicity of hydrogen peroxide produced by electroplated coatings to pathogenic bacteria.

The ability of various electroplated coatings (cobalt, zinc, copper, and cobalt-containing alloys of nickel, zinc, chromium, etc.) to inhibit the growth of pathogenic bacteria (Gram-positive bacteria Enterococcus faecalis and methicillin-resistant Staphylococcus aureus and Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae) was determined by a drop-method antibacterial experiment. The amounts of H2O2 produced and metal ions dissolved from the surfaces of various electroplated coatings were measured and it was found that the inhibitory ability of coatings corresponded to the amounts of H2O2 produced. The more significant the inhibition of the coating to bacterial growth, the greater the amount of H2O2 production. In addition, the bacterial survival rates on the surfaces of coatings were almost zero when H2O2 was produced in amounts greater than 10(-6) mmol/cm2. However, the dominant concentrations of metal ions dissolved from coatings were outside of the bacterial lethal range.

Corrosion↗
PubMed2006

Survey of urinary nickel in residents of areas with a high density of electroplating factories.

The soil metal contamination arising from the discharge of the high density of electroplating factories in the geographic center of Taiwan has prompted concern about human exposure to harmful metals. This study aimed to determine the levels of nickel (Ni) in urine of residents living in the high vs. low factory-density areas, and to examine how these levels relate to gender and age. A total of 660 subjects, resident in the area for the last five years, were sampled according to the stratified random sampling approach, at ages 35-44, 45-54, and 55-64years for both genders. Metals in urine samples were analyzed by inductively coupled plasma mass spectrometry (ICPMS). The geometric mean (95% confidence interval (CI)) of urinary Ni was 6.30 (5.99-6.62)mug/l. The 0.95 parametric reference interval (90% CI) of urinary Ni was estimated to be 1.74 (1.62-1.88) to 22.73 (21.14-24.44)mug/l. Subjects in the areas with a high density of electroplating factories had significantly higher urinary Ni levels than those in the low-density areas, but both types of areas had obviously higher urinary Ni levels when compared to the non-occupationally exposed population from western countries. The health significance of elevated urinary Ni and its causative factors remain to be determined.

Adult↗