Pickling Solution Research Articles

Effects of different copper salts on the physicochemical properties, microstructure and intermolecular interactions of preserved egg white

This study was conducted to investigate the effects of different copper salts on the physicochemical properties, microstructure and intermolecular interactions of preserved egg white (PEW) during pickling. With increased pickling time, the alkalinity of the pickling solution and the moisture of PEW pickled by three copper salts (CuSO4, CuCl2 and Cu(CH3COO)2) gradually decreased, while the pH showed dynamic trends. During the early stage of pickling, the viscosity of PEW changed dynamically. With the progress of pickling, the hardness and springiness of PEW increased gradually and the α-helix structure gradually transformed into a more stable β-structure. The main forces that maintained PEW gel were ionic and disulfide bonds. In the early stage of pickling, the alkali penetration rate of CuCl2 pickled preserved eggs was faster, and better gel strength and network structure were observed, followed by CuSO4 and Cu(CH3COO)2, while there were no significant differences in the later stage of pickling.

The behavior of two indazole derivatives on the copper/sulfuric acid interface in terms of adsorption and corrosion inhibition

BackgroundTo reduce the degree of copper corrosion by the pickling solution, the introduction of organic inhibitors into the pickling solution is a reasonably effective measure.5-fluoro-1H-indazole (5-FIA) and 5‑chloro-1H-indazole (5-CIA) may act as exceptional inhibitors. MethodsBased on experimental and theoretical methods, the antiseptic ability of two indazole derivatives on copper in sulfuric acid was researched. Significant findsThe results of electrochemical experiments show that in the test solution containing 1 mM inhibitors, the corrosion inhibition efficiency (η) of 5-FIA and 5-CIA was 90.4% and 94.3%, respectively, indicating that 5-FIA and 5-CIA have outstanding corrosion inhibition capabilities and their antiseptic effects are in the order of 5-FIA < 5-CIA, which is also confirmed by observations of Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Furthermore, both 5-FIA and 5-CIA are mixed-type inhibitors and their adsorption behavior follows Langmuir isothermal adsorption model. The results of X-ray Photoelectron Spectroscopy (XPS), theoretical calculations, and molecular dynamics simulations further reveal the mechanism that 5-CIA has stronger adsorption capacity than 5-FIA.

The role of metal compounds in dynamically regulating alkali infiltration during pickling of preserved eggs

This study was conducted to investigate the dynamic regulation of alkali infiltration by different metal compounds during the pickling of preserved eggs. With the increased pickling time, the alkalinity of the pickling solution decreased, while the pH of preserved egg white increased firstly, then decreased, and finally increased again. The metal ions corresponding to the added metal compounds (CuSO4, CuSO4/ZnSO4 and PbO) underwent a complex migration with pickling time, and their content gradually increased in eggshell and yolk, but showed complex changes in egg white. The addition of metal compounds could produce a plugging effect. The main components of the black spots on eggshells of preserved eggs pickled by CuSO4, CuSO4/ZnSO4, and PbO were Cu2S, Cu2S/ZnS and PbS, respectively. In short, different metal compounds were combined with H2S to form insoluble compounds to block eggshell stomata, mesh pores and corrosion pores, thereby dynamically regulating the penetration of alkali.

Electrolytic Recovery of Metal Cobalt from Waste Catalyst Pickling Solution.

Terephthalic acid production plant uses liquid cobalt–manganese bromide as a catalyst. The waste catalyst is burned with exhaust gas and accumulated in fly ash, which is further pickled and impregnated with a sulfuric acid solution. The resultant solution is rich in cobalt and manganese metal ions with few metal impurities from other petroleum raw materials. An electrochemical reduction method is used to recover cobalt metal from the waste catalyst fly ash pickling solution of terephthalic acid. Various steps have been taken to remove impurities and extract and separate the required pure cobalt metal solution. Afterward, the process of electrolytic reduction smelting is conducted. Variables investigated include current density, electrolyte pH, electrode materials, and electrolytic cell diaphragms, among several others. Results show that the product purity can reach up to 99.84% for the electrolyte feed composition of 21.4 g L−1 Co, 38.2 g L−1 Na, and 2.02 g L−1 Mg.

FUZZY ESTIMATION PROCEDURE OF THE CONCENTRATION OF THE COMPONENTS OF A SULFURIC ACID PICKLING SOLUTION

The article is devoted to the issue of determining the level of concentration of individual components of working solutions. The relevance of the topic lies in the fact that some impurities in solutions (for example, when pickling steel) cannot be measured automatically, which reduces the efficiency of the process and increases the load on the solution regeneration section. Also, impurities are hazardous waste for the environment and humans.&#x0D; The development of a method for the operational control of the composition of the pickling solution components in pickling baths is the main task of the work. A detailed substantiation of the choice of the mathematical apparatus of the method is given. The process of fuzzy identification of the composition of the components is carried out by the number of pixels with certain digital color RGB codes from digital images of the control doses of the solution. A set of technical means for providing the method for practical implementation in the technological process is described. A prototype of a graphical user interface (GUI) for the proposed method for identifying the composition of technological liquid solutions, developed in the Processing 3.0 integrated environment using applications from the Open Source Computer Vision Library, is presented.&#x0D; A technique for extracting experimental data for filling the base of a fuzzy classifier with model reference points is proposed. Its essence lies in simultaneous measurements of the concentration of the components of the pickling solution by classical methods of titration and dry residues and the proposed method with a step equal to the regulated accuracy. The results of approbation of the proposed method are presented.&#x0D; The presented technique for obtaining a fuzzy classifier can be used to develop IT tools for the operational control of the composition of various liquid solutions with opaque colored components and color identification of defects in various flat surfaces, provided that they are color distinguishable and determine the boundaries of RGB - intervals for assessing the color of individual component (defects).

Recovery of Hydrochloric Acid from Industrial Wastewater by Diffusion Dialysis Using a Spiral-Wound Module.

In the present study, the possibility of using a spiral-wound diffusion dialysis module was studied for the separation of hydrochloric acid and Zn2+, Ni2+, Cr3+, and Fe2+ salts. Diffusion dialysis recovered 68% of free HCl from the spent pickling solution contaminated with heavy-metal-ion salts. A higher volumetric flowrate of the stripping medium recovered a more significant portion of free acid, namely, 77%. Transition metals (Fe, Ni, Cr) apart from Zn were rejected by >85%. Low retention of Zn (35%) relates to the diffusion of negatively charged chloro complexes through the anion-exchange membrane. The mechanical and transport properties of dialysis FAD-PET membrane under accelerated degradation conditions was investigated. Long-term tests coupled with the economic study have verified that diffusion dialysis is a suitable method for the treatment of spent acids, the salts of which are well soluble in water. Calculations predict significant annual OPEX savings, approximately up to 58%, favouring diffusion dialysis for implementation into wastewater management.

Modified chemical mineralization-alkali neutralization technology: Mineralization behavior at high iron concentrations and its application in sulfur acid spent pickling solution

Mineralization coupled with neutralization is a dual-function technology for disposing acidic iron-rich waters, which can recover the valuable iron in the form of secondary mineral and concurrently purify the wastewater. In this study, a modified technology for treating high Fe wastewater (sulfur acid spent pickling liquor, 62 g Fe/L) was proposed based on the specific investigation of the mineralization behaviors in Fe concentration range of 20–70 g/L. Results showed that high SO42−/Fe2+ molar ratio (> 2.0) tended to trigger gelation phenomena at Fe concentrations above 30 g/L. Fe specie distribution suggested that the insufficient polymerization among Fe-OH complexes might be responsible for the gelation phenomena, since the strong Fe-SO4 coordination almost completely suppressed the Fex(OH)y(3x-y)+ form (a general terms of Fe3+ hydrolysates and their polymers). Modified mineralization strategies were proposed, including pretreatment with dilution or BaCl2/CaCl2 precipitation, of which CaCl2 pretreatment was a versatile and low-cost method. Following CaCl2 pretreatment, chemical mineralization converted above 90% of iron into secondary mineral, which therefore drastically reduced the alkali consumption (from 164.2 g/L to 1.4 g/L) and sludge yield (from 328.1 g/L to 2.4 g/L) in subsequent neutralization treatment. The resultant mineral was identified as schwertmannite, and exhibited efficient adsorption capacity toward arsenite (364.2 mg/g). The modified chemical mineralization-alkaline neutralization is a cost-effective technology for the treatment of the acidic iron-rich waters. In practical applications, several regulating strategies should be further explored to improve the mineral purity, and the mineralization conditions must be optimized according to the Fe and SO42− concentrations in wastewater.

One-Pot Hydrothermal Synthesized Nitrogen and Sulfur Codoped Carbon Dots for Acid Corrosion Inhibition of Q235 Steel.

N and S codoped carbon dots having good water solubility have been successfully made by a novel hydrothermal method and characterized by FTIR, XPS, and TEM. The as-synthesized CDs were carbon particles rich in polar functional groups less than 10 nm in size. Electrochemical measurements, gravimetry, and surface analysis methods were utilized to examine the inhibition characteristics and adsorption mechanism of CDs on the carbon steel in acid pickling solutions. Electrochemical measurements verified that the CDs displayed adequate protection with high inhibition efficiency of 97.8%. The long-term weight-loss experiments up to 72 h further confirmed the excellent corrosion inhibition at room temperature and 313 K. The results presented are helpful for the formulation of more effective acid pickling corrosion inhibitors.

Development of novel green methods for preparation of lead-free preserved pidan (duck egg).

Pidan, a pickled duck egg, is a traditional Chinese cuisine and generally produced by soaking in metal ion containing strong alkaline solution such as NaOH solution. However, nowadays consumers possess negative perception for using strong alkali in food processing. Therefore, the objective of the current study was to determine the potential of incinerated eggshell powder and alkaline electrolyzed oxidized (EO) water for pidan production rather than harmful NaOH use. This study aims to obtain the optimal physicochemical and sensory qualities of pidan. Various dosing (1-5%) of the incinerated eggshell powder solution or alkaline EO water was used as a basic pickling solution. Duck eggs were pickled at 25-27°C for 15-30days with 3days of an observation interval. Actual commercial process commonly undergoes for 14days of ripening, after 25days of picking process with incinerated eggshell powder or EO water. Results showed that physicochemical and sensory attributes of pidan obtained by incinerated eggshell powder solution and alkaline EO water were not significantly different (P < 0.05) from the commercial product. This study reports a cost-effective and green alternative method for pidan processing by replacing costly NaOH without compromising their physico-chemical and sensory attributes.

Impact of corrosion on mechanical properties of additively manufactured Invar 36

AbstractInvar alloys are used for high‐precision applications due to their invariance of the coefficient of thermal expansion over a temperature range up to about 250 °C. The present study determines the mechanical and corrosive properties of Invar 36 (64 % Iron – 36 % Nickel) specimens produced by laser powder bed fusion. Tensile specimens were fabricated to investigate the mechanical properties. The influence of a horizontal and vertical building orientation is considered. An apparent mechanical anisotropy depending on the respective building is observed. Based on this, further tensile specimens were stored in a hydrochloric acid pickling solution, a sulphate buffer solution and a sodium chloride solution to analyse the corrosion behaviour. The findings after eight weeks in the individual media show that outsourcing the Invar 36 specimens in a sulphate buffer solution results in significant changes in the mechanical properties, especially fracture elongation.

Economic Benefits of Waste Pickling Solution Valorization.

An integrated hybrid membrane process, composed of a diffusion dialysis (DD), a membrane distillation (MD) and a reactive precipitation unit (CSTR), is proposed as a promising solution for the valorization and onsite recycling of pickling waste streams. An economic analysis was performed aiming to demonstrate the feasibility of the developed process with a NPV of about EUR 40,000 and a DPBP of 4 years. The investment and operating costs, as well as the avoided costs and the benefits for the company operating the plant, were analyzed with an extensive cost tracking exercise and through face-to-face contact with manufacturers and sector leaders. A mathematical model was implemented using the gPROMS modelling platform. It is able to simulate steady state operations and run optimization analysis of the process performance. The impact of key operating and design parameters, such as the set-point bath concentration and the DD and MD membrane areas, respectively, was investigated and the optimal arrangement was identified. Finally, operating variables and design parameters were optimized simultaneously in a nonlinear framework as a tradeoff between profitability and environmental impact. We show how the integration of new technologies into the traditional pickling industry could provide a significant benefit for the issues of process sustainability, which are currently pressing.

Immersion pickling of oxide layer on hot-rolled 2205 duplex stainless steel in sulfuric acid with different additives

The oxide layer formed after hot-rolling of duplex stainless steel (DSS) alloy 2205 was studied by electron probe microanalysis (EPMA) with wavelength dispersive spectrometry (WDS). Immersion pickling of the oxide layer on hot-rolled 2205 DSS in sulfuric acid at 80 °C with different additives was investigated via open-circuit potential and SEM imaging. The effects of different pickling solutions on descaling capacity were discussed. Results showed that the outer layer of the oxide layer was mainly iron oxide, whereas the maximum concentration of oxidized Cr occurred inside the layer; oxidized Cr extended far beyond the oxide/metal interface. The removal capacity of the oxide layer was weak with a sulfuric acid solution of 300 g/L. Many surface oxides appeared after the 20 min immersion test. After adding 1 mol/L NaCl, the pickling effect was significantly improved, and the open-circuit potential reduced from 0.3V to –0.32V. However, after a 20-min substrate immersion test, the surface was rough. Continuous addition of 50 g/L hexamethylenetetramine could remove the oxide in 20 min, resulting in a surface with a metallic luster. The initial potential of the reaction was –0.325 V. The potential then rose rapidly to –0.312 V within 280 s. The rapid increase in potential could be attributed to the inhibitory effect of hexamethylenetetramine. The optimum pickling process was as follows: 300 g/L H2SO4 + 1 mol/L NaCl+ 50 g/L hexamethylenetetramine solution at 80 °C in 20 min.

A universal strategy for green and in situ synthesis of carbon dot-based pickling solution

A universal strategy for green and in situ synthesis of carbon dot-based pickling solution with high inhibition efficiency.

Assessment of different pickling solutions on quality characteristics of pickled quail (&lt;i&gt;Coturnix coturnix japonica&lt;/i&gt;) eggs

The Journal of Agriculture and Value Addition is a research journal produced and published by the Faculty of Animal Science and Export Agriculture, Uva Wellassa University of Sri Lanka. lt creates an opportunity for effective and healthy communication of findings from the national and international research community representing main myriad disciplines of agriculture such as crops, livestock, aquaculture and fisheries focusing on value addition.

Selective dissolution during acid pickling of aluminum alloys by element-resolved electrochemistry

The surface reactivity and the elemental dissolution of a high-strength aerospace alloy (AA7449-T651) during acid pickling was investigated with element-resolved electrochemistry (AESEC). The results demonstrated a sequential dissolution of Mg, Al, Zn and Cu, following the order of their respective galvanic reactivity in common acid pickling solutions. The enrichment of Cu during pickling with the H2SO4 solution was observed. The effect of oxidizing solution components HNO3 and Fe(III) on Cu dissolution were investigated using an experimental Evans diagram approach.

Solvent extraction and separation of zinc-iron from spent pickling solution with tri-n-octylamine

Studies on the effective extraction and separation of zinc-iron from spent pickling solution using tri-n-octylamine (TOA) with solvent extraction were investigated. Single extraction efficiency of 83.75% is obtained under the optimal conditions (organic phase consisting of 30% (v/v) extractant TOA, 20% (v/v) modifier iso-octanol, and 50% (v/v) diluent sulfonated kerosene, organic phase volume: aqueous phase volume of 2:1, and extraction time 10 min), while only 1.8% iron is co-extracted. McCabe-Thiele diagram is employed to analyze the number of theoretical stages needed for the effective extraction of zinc, and it is found that under five-stage counter-current extraction, almost all the zinc ions are extracted. A stripping efficiency of more than 90% from the loaded organic phase is achieved by 2.0 mol/L NH3·H2O and organic phase volume: aqueous phase volume of 1:2. Furthermore, the extraction mechanism of zinc with TOA accompanied by anion exchange is demonstrated by FT-IR spectra analysis and ESI-MS analysis, and the structure of the extracted complex is confirmed as [R3NHZnCl3].

Removal of impurities from bismuth pickling solution using solvent extraction with TBP

This work proposes an extraction process for thorough removal of various impurities in crude bismuth. In the process, crude bismuth was pickled with nitric acid, and then the bismuth in the filtrate was extracted into the organic phase by TBP. After scrubbing with a saturated NaNO3 solution, stripping was carried out by NaOH solution, and a rod-shaped α-Bi2O3 precipitate was obtained. Increasing the concentration of NO3− and TBP and the ratio of Vo/Va could greatly increase the extraction efficiency of bismuth or the separation factor of impurities. Bismuth is extracted in the form of Bi(NO3)3·TBP, and the results of quantum chemical calculations indicated that both intermolecular forces and chemical bonds exist between the Bi(NO3)3 and TBP molecules. Thermodynamic analysis based on the Debye-Hückel equation under large ionic strength conditions showed that the extraction reaction is exothermic and proceeds spontaneously. Under the optimized extraction conditions, the extraction efficiency, elution efficiency, and stripping efficiency of bismuth were 98.5%, 0.55%, and 96.2%, respectively. All of the impurity elements were thoroughly removed after extraction. In particular, the separation factor βBi/M of M = Te, As, Cu, and Sb, which are prone to codeposition with bismuth during electrodeposition, were 160, 183, 982, and 359, respectively. The purity of α-Bi2O3 obtained by this method was as high as 99.95%

Utilization of waste sodium sulfate from battery chemical production in neutral electrolytic pickling

Several industrial activities produce metal sulfates, which are controlled by strict limitations for wastewater concentrations of sulfate. One emerging area where these activities occur is the production of lithium-ion battery chemicals in which sodium sulfates are formed because of cathode precursor co-precipitation. Several solutions for sulfate removal exist, but one option is to reuse the sulfate side stream in other processes to increase circular economy and atom efficiency. In this paper, the reuse of sodium sulfate solution in a steel industry pickling solution is considered. Neutral electrolytic pickling experiments were carried out to compare the pickling behavior of the electrolyte dissolved from pure sodium sulfate and the electrolyte diluted from a side stream solution. Effect of impure electrolyte was evaluated using field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectrometry (EDS). Concentrations of the metal ions were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). The results indicated a slight increase in current efficiency with the side stream electrolyte solution, while overall the pickling behavior remained similar. This suggests that a side stream sodium sulfate solution could be used as a pickling electrolyte, reducing the need for pure reagents.

Separation of copper from electroplating waste

Dumping and saving waste pickling solutions on the territory of enterprises leads to environmental pollution and requires significant costs at the plant and in wastewater treatment plants at the production sites when neutralizing them. The aim of the article is to present the results of research and tests in order to create environmentally friendly equipment. In this work, we studied the individual processes of regeneration of copperammonia pickling solutions with the production of dense copper deposits, the release of which drastically reduces the formation and storage of waste in the form of sludges in the territory of enterprises. It is pointed out that the chemical correction of etching solutions leads to the formation of a significant amount of wastewater, which contains heavy metals that adversely affect soils, groundwater, the plant world and humans, as the top of the food chain. The creation of equipment for the regeneration of used solutions with the release of metal in a form suitable for melting becomes an important element of environmental conservation and a cost-effective element of the process. The PCB etching line, created on the basis of research, allows for reusage in the technological process of wastewater after its recovery (regeneration) and use for the etching of the substrate of the printed circuit boards. For the regeneration of a copper-alkaline solution, a continuous installation using a cathode made of stainless steel or titanium with a thickness of 3 mm and a graphite anode with a thickness of 30 mm was proposed. The results of individual tests that indicate the possibility of using separated copper for metallization of substrates in the corresponding technological processes or after remelting for electrical purposesare presented. The use of a process with the precipitation of copper by dense precipitation makes it easier to remove metal by simple mechanical operations and to avoid a complex structure for the extraction of copper in the form of metal powders.

Green synthesis and anticorrosion effect of Allium cepa peels extract-silver nanoparticles composite in simulated oilfield pickling solution

An alternative green approach through which nanoscience/nanotechnology could be applied in the industry is being demonstrated in this study. Ethanol extracts of Allium cepa peels (Et-ACPE) is used to mediate the synthesis of silver nanoparticles (Et-AgNPs) at room temperature. Stable crystalline, monodisperse and non-agglomerated spherical NPs with zeta potential of −46.2 ± 0.1 mV and plasmon absorption at 435 nm are obtained. Silver atoms are predominantly oriented towards the Ag (111) plane in a face centered cubic structure with a = b = c = 4.0968 Å having alpha = beta = gamma = 90^circ. The surfaces of the NPs becomes rich in electron cloud due to O atoms supplied by capped phyto-compounds of Et-ACPE. This enhances adsorption potential and more efficient inhibition (up to 90% at 30 °C) of X80 steel corrosion in 1 M HCl solution than using the crude extract. Investigation of corrosion products and morphologies of the steel surface by FTIR, SEM/EDS and AFM techniques reveals efficient surface protection through adsorption of Et-AgNPs facilitated mainly by O and –C = C– sites. Findings prove that the Et-AgNPs is a more efficient and thermally stable alternative ecofriendly anticorrosion additive for industrial cleaning and pickling operations than the crude extract.