Sulfite Treatment Research Articles

Enhanced H2 photoproduction in sodium sulfite-treated Chlamydomonas reinhardtii by optimizing wavelength of pulsed light

Photosynthetic hydrogen induced by Chlamydomonas reinhardtii presents a promising pathway for producing clean and renewable biofuel. Whereas, this process is transient owing to the repression of [FeFe]-hydrogenase by the oxygen co-evolved in photosystem II. Pulsed light is employed to prevent O2 accumulation and the activation of Calvin-Benson-Bassham cycle for sustainable H2. While light quality significantly influences photosynthesis, the optimal wavelength for pulsed light-induced H2 production remains not fully elucidated. Continuous irradiation at 660–670 nm performs poorly in H2 production due to the activation of PSII, which is responsible for water oxidation. However, in this study, O2 was removed using a combination of pulsed light and sulfite treatment. Among six light regimes with different wavelengths, pulsed light peaking at 660 nm resulted in the highest photo-H2 evolution, reaching approximately 180 mL L−1 within three days. This value was 1.4 times higher than that achieved under conventionally white pulsed light. Exposure to 660 nm red pulsed light not only sustained high activity of PSII and hydrogenase but also reduced the gene expression levels of ribulose-1,5-bisphosphate carboxylase/oxygenase and ferredoxin-NADP+ reductase, which was supposed to attenuate the competing effects of CBB cycle. This finding optimizes an efficient light source for pulsed light-induced H2 production and demonstrates a great potential for refining pulsed light parameters to improve H2 production in algae in the future.

In-situ sulfite treatment promotes solid reduction during aerobic digestion of waste activated sludge: Feasibility for small-scale wastewater treatment plants

Aerobic digestion remains the preferred choice for small-scale wastewater treatment plants (WWTPs) in some developing countries, largely due to economic viability and operational simplicity. The escalating production of waste activated sludge (WAS) has prompted small-scale WWTPs to improve efficiency. To address this issue, this study employed an in-situ sulfite treatment as a non-intrusive method to augment aerobic digestion. With sulfite-enhanced solubilization and hydrolysis, a 3.6-fold increase in degradation was achieved. Both sludge dewatering properties and pathogens inactivation were improved. Microbial community analysis revealed a preferential enrichment of Actinobacteriota and Firmicutes during sulfite treatment. The desktop scaling-up estimation suggests that implementing this treatment yielded operational cost savings exceeding 40 %. In summary, in-situ sulfite treatment offers a cost-effective strategy for WAS management in small-scale WWTPs.

Effect of pH on antibiotic resistance genes removal and bacterial nucleotides metabolism function in the wastewater by the combined ferrate and sulfite treatment

The variations of the antibiotic resistance genes removal and the bacterial nucleotide metabolism function in the wastewater by the combined ferrate and sulfite treatment at different pH levels were investigated. The total DNA as well as the genes sul2, sul3 and intI1 removal by the combined 10 mg/L ferrate and 28.5 mg/L sulfite treatment and the contributions of the sulfate radicals and the hydroxyl radicals produced by the reaction of ferrate with sulfite to the DNA removal decreased as the pH increase from 6.0 to 9.0. Bacterial nucleotide metabolism level changes affected the DNA removal, and the highest nucleotide degradation metabolism level and the lowest level of the nucleotide biosynthesis and salvage metabolism were found at pH 6.0. The reduction of the genes sul2, sul3 and intI1 host level contributed to the genes sul2, sul3 and intI1 removal. This study provides novel insights into the antibiotic resistance genes removal by the combined ferrate and sulfite treatment at different pH levels.

Sulfite incorporated thermoplastic cassava starch blended PBAT blown films as antimicrobial and antibrowning packaging

Microbial growth and browning cause quality loss in intermediate moisture foods. This research developed and characterized novel active films to prevent microbial growth and brown discoloration in dried meat and fruits. Biodegradable films based on thermoplastic starch (TPS) and poly(butylene adipate-co-terephthalate) (PBAT) blends incorporating sodium metabisulfite (SM) (up to 7% w/w) were developed using blown film extrusion. SM interacted with the TPS phase, involving O-H stretching vibration and hydrogen bonding which modified the thermal degradation behavior of the TPS phase and improved the smoothness of the film microstructures. Excessive SM formed crystal particles at ≥ 3% that were detected by X-ray diffraction. Addition of SM decreased the mechanical properties but film clarity and hydrophobicity improved, with enhanced water vapor barrier properties. The SM blend film showed significant antibacterial activity against E. coli, B. cereus, and S. aureus. TPS/PBAT/SM active films effectively prevented mold growth and darkening in packaged salami for at least 16 days, while the non-SM blend film was only effective for 6 days at room conditions. Active films with SM loading, particularly at > 3% prevented browning reaction and darkening in dried bananas and longans at both ambient (60% RH) and 85% RH stored at room temperature. SM addition improved packaging characteristics and functional efficiency, resulting in higher dried fruit and meat product quality. TPS/PBAT/SM composite films showed promise as sustainable active packaging and an alternative technique to sulfite treatment for dried fruit and meat.

Two-stage sulfite steam pre-treatment achieves extraordinary bioethanol titer from simultaneously saccharification and fermentation of softwood whole slurries

Softwood biomass, which contains rich portion of readily fermentable sugars, is a type of abundant biomass in Canada and Nordic countries. However, its recalcitrant structure has severely limited its utilization in bioconversion. Sulfite treatment during steam pre-treatment to simultaneously enhance ease of hydrolysis and fermentation of softwood biomass has turned to be an attractive strategy to unlock the possibility of converting softwood to bioethanol. Our previous work showed applying one-stage sulfite treatment during the steam pre-treatment under neutral/alkaline conditions could maximize the sulfonation/delignification and hemicellulose sugar retention, while the use of acidic conditions could enhance the homogenous substrates size reduction. To take the advantages of both the neutral/alkaline and acidic conditions, we developed two-stage sulfite steam pre-treatment to maximize the sugar and ethanol production by utilizing Na2SO3 in the first alkaline steam pre-treatment stage and SO2 in a second acidic steam pre-treatment stage. The resulting substrates showed high sulfonation/delignification extent, nearly 100 % sugar recovery, homogeneous substrates size reduction and sufficient detoxification. Without extra hydrolysate detoxification and concentration, 160 g/L fermentable sugars were obtained from the hydrolysis of two-stage sulfite steam pretreated softwood whole slurry at 25% solid loading. And 80 g/L ethanol was generated by directly fermenting these sugars in the whole slurry hydrolysate without additional detoxification or concentration processes. This work significantly contributed to the development of the industrial relevant bioethanol production from softwood biomass.

Исследование виноградных субпродуктов для получения биоэтанола на основе новых устойчивых штаммов

Technological development of environmentally friendly biofuels is highly desirable due to the depletion of fossil fuel reserves and increased environmental awareness. Currently, bioethanol appears to be the key alternative fuel, most of which is made from sugar cane, corn, and wheat. However, the use of these sugar- and starch-basedmaterials is still controversial due to their alternative use as animal feed and as raw materials for human staple foods. Various detoxification strategies have been developed to remove these inhibitors from lignocellulose hydrolysates and reduce their levels, such as alkali treatment, sulfite treatment, evaporation, anion exchange and laccase addition.However, these methods create 2 main problems in terms of their technical and economic feasibility: the addition of expensive processing stages and the loss of easily digestible sugars.

Effects of Different Delignification and Drying Methods on Fiber Properties of Moso Bamboo.

Bamboo has become an important kind of fibrous raw material in the world due to its fast-growing property and abundance of natural fiber. During the purification and utilization of bamboo fiber, the removal of lignin is vital and it is affected by the chemical treatment system and drying method. In this paper, the effects of three different delignification chemical systems and three drying methods (air drying, drying and freeze drying) on the physical and chemical properties of bamboo fiber were comparatively studied. The results prove that all three delignification techniques can effectively remove lignin from wood, and by utilizing peroxyformic acid and alkaline sodium sulfite, hemicellulose can be removed to a certain extent. With the selective removal of amorphous hemicellulose and lignin and the hydrolysis of cellulose molecular chains in amorphous regions, all three treatments contributed to an increase in the relative crystallinity of cellulose (ranging from 55% to 60%). Moreover, it was found that the drying methods exerted a certain influence on the mechanical properties of fiber. For instance, drying or air drying would improve the tensile strength of fiber significantly, approximately 2-3.5 times that of original bamboo fiber, and the tensile strength of the drying group reached 850-890 MPa. In addition, the alkaline sodium sulfite treatment had little effect on the thermal stability of bamboo fiber, resulting in high thermal stability of the prepared samples, and the residual mass reached 25-37%. On the contrary, the acetic acid/hydrogen peroxide method exerted great influence on the thermal stability of bamboo fiber, giving rise to a relatively poor thermal stability of prepared fibers, and the residual mass was only about 15%. Among the three drying methods, samples under air drying treatment had the highest residual mass, while those under freeze drying had the lowest. To summarize, the alkaline sodium sulfite method is more suitable for preparing bamboo fiber with higher tensile strength and thermal stability.

In Situ Lignin Sulfonation for Highly Conductive Wood/Polypyrrole Porous Composites

AbstractTo address the rising need of sustainable solutions in electronic devices, the development of electronically conductive composites based on lightweight but mechanically strong wood structures is highly desirable. Here, a facile approach for the fabrication of highly conductive wood/polypyrrole composites through top‐down modification of native lignin followed by polymerization of pyrrole in wood cell wall. By sodium sulfite treatment under neutral condition, sulfonated wood veneers with increased porosity but well‐preserved cell wall structure containing native lignin and lignosulfonates are obtained. The wood structure has a content of sulfonic groups up to 343 µmol g−1 owing to in situ sulfonated lignin which facilitates subsequent oxidative polymerization of pyrrole, achieving a weight gain of polypyrrole as high as 35 wt%. The lignosulfonates in the wood structure act as dopant and stabilizer for the synthesized polypyrrole. The composite reaches a high conductivity of 186 S m−1 and a specific pseudocapacitance of 1.71 F cm−2 at the current density of 8.0 mA cm−2. These results indicate that tailoring the wood/polymer interface in the cell wall and activating the redox activity of native lignin by sulfonation are important strategies for the fabrication of porous and lightweight wood/conductive polymer composites with potential for sustainable energy applications.

46 Sulfonation-Based Decontamination Alters Biotransformation and Excretion of Deoxynivalenol in Nursery Pigs

Abstract Deoxynivalenol (DON) is a primary mycotoxin in cereal feed ingredients that negatively affects feed intake and immune function of pigs. Formation of DON sulfonate (DONS) with sulfites in feed has become an effective approach to mitigate the DON toxicities in practice, but the metabolic fate of DON under sulfonation-based decontamination was not well defined. In this study, 48 nursery pigs (35 d of age, 10.8 ± 1.3 kg) were stratified by weight and sex and grouped following a 2 x2 factorial design on the DON content in corn-soybean meal diets (1.2 vs. 4.1 ppm) and the inclusion of NoTox Ultimate D, a sulfite-based mitigant (0 vs. 0.25%). Four experimental diets, including low-DON feed with no mitigant treatment (LD-NT); low-DON feed with sulfonation treatment (LD-ST): high-DON feed with no mitigant treatment (HD-NT); high-DON feed with sulfonation treatment (HD-ST), were fed for 21 d for urine collection on day 0, 10, and 21 and fecal collection on day 21. Urine and fecal samples were analyzed by both targeted metabolite analysis and untargeted metabolomic modeling. DON itself was absent in all fecal and urine samples, indicating a complete biotransformation. As expected, sulfonation led to the formation of DONS in feces in correlation with the DON content in feed and the decrease of two DON glucuronides in urine (HD-ST < HD-NT). Interestingly, sulfonation did not decrease the concentrations of two deepoxy-deoxynivalenol (DOM) glucuronides in urine. Instead, it significantly increased DOM in feces (HD-ST > HD-NT). The results indicate that the formation of DONS by sulfite treatment alters the biotransformation and excretion of DON by decreasing the availability of free DON for absorption and simultaneously increasing its availability for microbial metabolism to form DOM, an inactivated metabolite, for fecal and urine excretion.

Fate and transformation of iodine species during Mn(VII)/sulfite treatment in iodide-containing water.

During oxidative treatment of iodide (I- )-containing waters, I- is easy to be oxidized into hypoiodous acid (HOI) by various oxidants and the further reaction of HOI with organic compounds can lead to the formation of iodinated disinfection by-products (I-DBPs). Oxidation of HOI to iodate (IO3 - ) or reduction of HOI to I- has been proposed to reduce the formation of I-DBPs. Because the reaction of HOI with sulfite proceeds rapidly, this study examined the fate of iodine and the formation of I-DBPs in Mn(VII)/sulfite process. Results showed that I- was oxidized to HOI but the further formation of IO3 - was suppressed due to the fast reduction of HOI to I- by sulfite. The reactions of HOI with SO3 2- and IO- with SO3 2- are the major pathways with species-specific second-order rate constants determined to be 1.12 × 105 M-1 s-1 and 9.43 × 107 M-1 s-1 , respectively. The rapid reaction of HOI with sulfite plays an essential role in minimizing the formation of iodinated products in HOI- and phenol-containing solutions. The toxic risk analysis showed that the toxicity of the generated DBPs from Mn(VII)/sulfite pre-oxidation followed by chlorination only changed slightly. PRACTITIONER POINTS: The decay of I- was negligible in Mn(VII)/sulfite process. The rapid reaction of HOI with SO3 2- resulted in the negligible generation of IO3 - . Mn(VII)/sulfite process exerted slight influence on the formation of I-DBPs. Mn(VII)/sulfite process is promising for the pretreatment of I- -containing water.

Effect of different packaging methods on the free amino acid profiles of the deep-water rose shrimp (Parapenaeus longirostris) during frozen storage.

The composition of free amino acids (FAAs) in seafood products contributes to characterizing their flavor, as well as freshness and quality during storage. Deep-water rose shrimps (Parapenaues longirostris, Lucas, 1846) (DWRS) are being increasingly harvested in the Mediterranean Sea, and the captured specimens are quickly frozen onboard fishing trawlers to preserve freshness and post-harvest quality. Here, we quantified the FAA profiles of DWRS packaged using five methods: (1) 100% N2; (2) vacuum; (3) 50% N2 + 50% CO2; (4) commercial anhydrous sodium sulfite; and (5) air (control). All samples were quickly frozen at −35°C and stored for 12 months at −18°C. Arginine (661 mg/100 g), proline (538 mg/100 g), and glycine (424 mg/100 g) were the most abundant FAAs, whereas the least abundant were tyrosine (67 mg/100 g), histidine (58 mg/100 g), and aspartic acid (34 mg/100 g). FAAs in all samples gradually (and significantly) increased in the first 6 to 8 months of storage, and then significantly decreased. The sodium sulfite treatment (Method 4) kept the initial FAA contents lower than the other treatments, due to the strong antioxidant action of sulfite agents. Interestingly, similar results were obtained for vacuum packaging (Method 2). Thus, combining frozen storage with vacuum packaging represents an alternative approach to chemical additives in shrimp/prawn processing to meet the increasing demand for high-quality seafood products with long shelf-life.

Impacts of Pretreatment Techniques on the Quality of Tuber Flours.

Besides dietary sources of energy, roots and tuber crops can also serve as functional foods and nutraceutical ingredients to be explored in disease risk reduction and wellness. However, they are easily spoiled because of their high moisture contents and enzymatic reactions. Therefore, this review aimed at gathering information on the effects of various pretreatment methods on the quality of tuber crops before converting them into flour. Studies reported by different scholars showed that there were significant differences in physicochemical and functional properties between untreated tuber and the treated tuber samples. The review also highlighted that the chemical treatment methods, particularly sulfite treatment, could increase the lightness value of the flour. In addition, blanching could induce a decrease in protein, ash, and fat. Despite this, blanching pretreatment techniques increased moisture and carbohydrate content. Chemical treatment increases the ash content, which might be responsible for chemical diffusion into the sample. The reviewed results showed that the application of different pretreatments on tuber crops significantly improves many quality characteristics such as color, fiber content, carbohydrate, and the functional properties used for value addition during food product development in the industry. Therefore, application of pretreatment methods particularly chemical treatments could enhance nutritional value, and functional and physical properties of tuber flours.

Sulfite-free treatment combined with modified atmosphere packaging to extend trimmed young coconut shelf life during cold storage

Sulfite solution has been commonly used on trimmed young coconut (TYC) and other produce to prolong shelf life, but it has been banned in many countries due to its allergenic reaction in sensitive individuals. This study has developed sulfite-free treatment together with modified atmosphere packaging (MAP) which could prolong shelf life of TYC during cold storage. The main goal of this work was to investigate qualities during cold storage at 2 °C for 8 weeks of TYC treated with salt/acid solution (15% sodium chloride and 20% citric acid) then packed in MAP at an oxygen transmission rate (OTR) of 3200 cm3/m2/day (SA-MAP), compared with a conventional sulfite agent treatment (KMS wrapped with PVC). Moreover, microbial profiles were investigated by next-generation sequencing (NGS), matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 18S rRNA gene sequencing. The result showed treatment of SA-MAP had effective control TYC qualities over 8-week storage comparable with the KMS treatment. Twelve genera of bacterial communities on TYC including Bacillus spp., Enterococcus sp., Enterobacter spp., Klebsiella sp., Kocuria sp., Lysinbacillus sp., Microbacterium sp., Micrococcus sp., Ochrobactrum spp., Pantoea spp. Staphylococcus spp. and Serratia sp. were the most abundant strains. On the other hand, microbial profiles of SA-MAP showed only Bacillus spp., Staphylococcus spp. and Candida spp. as the predominant microorganisms on TYC during cold storage. Using salt/acid combined with MAP was proposed as an alternative organic treatment to extend the shelf life of TYC for exportation.

Sulfite preservatives effects on the mouth microbiome: Changes in viability, diversity and composition of microbiota.

Processed foods make up about 70 percent of the North American diet. Sulfites and other food preservatives are added to these foods largely to limit bacterial contamination. The mouth microbiota and its associated enzymes are the first to encounter food and therefore likely to be the most affected. Eight saliva samples from ten individuals were exposed to two sulfite preservatives, sodium sulfite and sodium bisulfite. One sample set was evaluated for bacteria composition utilizing 16s rRNA sequencing, and the number of viable cells in all sample sets was determined utilizing ATP assays at 10 and 40-minute exposure times. All untreated samples were analyzed for baseline lysozyme activity, and possible correlations between the number of viable cells and lysozyme activity. Sequencing indicated significant increases in alpha diversity with sodium bisulfite exposure and changes in relative abundance of 3 amplicon sequence variants (ASV). Sodium sulfite treated samples showed a significant decrease in the Firmicutes/Bacteroidetes ratio, a marginally significant change in alpha diversity, and a significant change in the relative abundance for Proteobacteria, Firmicutes, Bacteroidetes, and for 6 ASVs. Beta diversity didn't show separation between groups, however, all but one sample set was observed to be moving in the same direction under sodium sulfite treatment. ATP assays indicated a significant and consistent average decrease in activity ranging from 24-46% at both exposure times with both sulfites. Average initial rates of lysozyme activity between all individuals ranged from +/- 76% compared to individual variations of +/- 10-34%. No consistent, significant correlation was found between ATP and lysozyme activity in any sample sets. Sulfite preservatives, at concentrations regarded as safe by the FDA, alter the relative abundance and richness of the microbiota found in saliva, and decrease the number of viable cells, within 10 minutes of exposure.

Effects of sulfite treatment on the quality of black fungus

In the present study, the color, total sugar, contents of soluble protein, total polyphenols, total flavonoids, and soluble vitamins, and other indicators of black fungus treated with sodium metabisulfite under different conditions were measured to evaluate the sensory and nutritional changes in black fungus after sulfite treatment. The results showed that use of sodium metabisulfite increased the lightness of black fungus, significantly increased the contents of total polyphenols and reducing sugars in the fungus (p < 0.05), increased the content of soluble protein, and decreased the content of total flavonoids. In addition, sodium metabisulfite destroyed vitamin C and B1 in black fungus. When the concentration of sodium metabisulfite was 0.5% and the soaking time 20 or 30 min, the color of black fungus improved markedly, and nutrients were not negatively affected. Therefore, the use of sodium metabisulfite improved the quality of fungus to a certain extent.

Structural properties and hydrolysability of recycled poplar residues (Populus L.): Effects of two-step acetic acid and sodium sulphite pre-treatment

Poplar trees rapidly yield wood and are therefore suitable as a biofuel feedstock; however, the quality of poplar is modest, and the profitability of poplar cultivation depends on the efficiency of the harvesting process. This study offers a simple and sustainable technique to harvest lignocellulosic resources from poplar for bioethanol production. The proposed two-step pretreatment method increased the surface lignin content and decreased the surface polysaccharide content. The cellulose content increased to 54.9% and the xylan content decreased to 6.7% at 5% AC. The cellulose yield of poplar residues (Populus L.) reached 65.5% by this two-step acetic acid (AC) and sodium sulphite (SS) treatment method. Two-step pretreatment using 5% AC and 4% SS obtained a recovery of nearly 80% of the total available fermentable sugar. The surface characterization showed a higher porosity in treated samples, which improved their hydrolysability. This method decreased the amount of lignin in plant biomass, making it applicable for further wood resource recovery or waste recycling for biorefinery purposes at very low costs.

Effect of Controlled Atmospheric Conditions Combined with Salt Acid Immersion on Trimmed Young Coconut Qualities During Cold Storage

Trimmed young coconut (TYC) contributes to global economic trade but it has major issues with microbial and browning spoilage during cold chain operation. A non-allergenic alternative to sulfite treatment is proposed in the present study. TYCs were dipped in salt acid solution (SA; 10% sodium chloride and 10% citric acid), stored in three different controlled atmosphere (CA) conditions and at an atmospheric condition as a control at 2 °C for 8 weeks. The physical, microbiological, chemical qualities of the TYCs were then determined during whole storage. The results indicate that use of SA combined with CA (5% O2 + 7.5% CO2) showed the best condition with the lowest average browning index of 29.13. The microbial counts were less than 4 log CFU/area with PCR-DGGE suggested an inhibition of some food spoilage bacteria. Titratable acidity, total soluble solid content, and pH ranged from 0.026-0.071%, 6.86-8.96 °Brix, and 5.38-6.51, respectively.

Perspiration promotes the effect of sulphite on the shielding response of rodent skin

Perspiration and environmental chemicals, such as air pollutants, are two of the complicating factors of skin disease. It has not been studied how perspiration affect the skin responding to air pollutants. We applied topically artificial eccrine perspiration, sulphite or both to the mouse skin for one and two weeks to examine the influence of both factors on the shielding ability of healthy skin. Morphological examination showed apparent thickening of the epidermal layer in the skin samples with combined treatment at 1 week, and in the sections applied with sulphite and combined treatment at 2 weeks without significant difference in the extent of epidermal hyperplasia between two groups. The outcomes of immunohistochemical (IHC) analysis showed elevated percentages of dermal fibroblasts expressing interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), tumor necrosis factor β (TNF-β) and cyclooxygenase-2 (Cox-2). Results of two-way repeated measured analysis of variance (two-way RMANOVA) showed that both perspiration and sulphite, but not the interaction between them, were significant factors affecting the expression of proinflammatory cytokines. The evidences indicated that perspiration induced cytokines expressions in the dermal fibroblasts and promoted the effect of sulphite on the shielding response of the skin by inducing epidermis hyperplasia.

Influence of Perspiration on Shielding Response of Rodent Skin to Sulphite

Perspiration and environmental chemicals, such as air pollutants, are two of the complicating factors of skin disease. It has not been studied how perspiration affect the skin responding to air pollutants. We applied topically artificial eccrine perspiration, sulphite or both to the mouse skin for one and two weeks to examine the influence of both factors on the shielding ability of healthy skin. Morphological examination showed apparent thickening of the epidermal layer in the skin samples with combined treatment at 1 week, and in the sections applied with sulphite and combined treatment at 2 weeks without significant difference in the extent of epidermal hyperplasia between two groups. The outcomes of immunohistochemical (IHC) analysis showed elevated percentages of dermal fibroblasts expressing interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), tumor necrosis factor β (TNF-β) and cyclooxygenase-2 (Cox-2). Results of two-way repeated measured analysis of variance (two-way RMANOVA) showed that both perspiration and sulphite, but not the interaction between them, were significant factors affecting the expression of proinflammatory cytokines. The evidences indicated that perspiration induced cytokines expressions in the dermal fibroblasts and promoted the effect of sulphite on the shielding response of the skin by inducing epidermis hyperplasia.

Experience of Ultrasonic Use to Stabilize Archaeological Iron Artifacts with Active Corrosion

Of all the complex problems of museum storage of archaeological objects, iron objects represent one of the most difficult. In the process of corrosion, an iron object passes through several stages, from oxidation of the metal surface to full mineralization. The greatest problem consists of the items in the stages of oxidation, when the metal is almost completely corroded and converted into minerals. Mineral peels exfoliate under the influence of active corrosion, leading to a loss of historical significance of the object. In the world’s practice of archaeological iron conservation, there are several different ways of stabilization, but none of them can guarantee the integrity of the iron artifact during its museum storage. To date, the most effective conservation method of stabilizing archaeological iron is alkaline sulfite treatment. However, this method has a number of drawbacks, the main of which is the duration of the stabilizing treatment. The authors consider the possibility of increasing the efficiency of the method of processing archaeological iron objects in an alkaline sulfite solution by means of ultrasonic solution activation. In the course of the experimental study, it has been established that the use of ultrasonic in alkaline sulfite treatment hugely increases the efficiency of the method.