Acid Soaking Research Articles

Structural modification of high carbon Co−Cr−Mo alloy via chemical etching to enhance hydroxyapatite coating performance

AbstractNumerous papers have been reported on surface treatment of metallic implant to facilitate positive interaction between the implant and hard tissue interface. In this paper, surface treatment such as chemical etching was done on the biomedical grade cobalt‐based alloy prior to hydroxyapatite coating deposition to enhance its biocompatibility. The objective is to investigate which temperature possesses the positive effect in adhesion strength of hydroxyapatite coating without detrimental the surface hardness. Observation showed that acid etched at the highest temperature (80 °C) has successfully roughen the substrate surface from 0.168 μm ±0.1 μm to 1.383 μm ±0.2 μm. Vickers hardness measurement on surface treated at 80 °C exhibit an increment of surface hardness which is about 39 % compared to surface treated at lower temperature. The highest thickness of hydroxyapatite coating layer (~57 μm) was evidently formed on the substrate etched at 80 °C with minimal cracks and no delamination. This phenomenon happened due to chemical reaction were rigorously attack on the substrate surface have provide more micro‐pits, pores and deeper craters that trap more efficiently of hydroxyapatite particles for thicker and dense coating formation. It is worth to note that too long acid soaking will also detrimental the material properties.

Multiplication and development in the nursery of Pterocarpus erinaceus, an endangered agroforestry species in Cote d'Ivoire

Pterocarpus erinaceus is a multi-purpose species threatened with extinction. The present study aims to contribute to the improvement of multiplication and nursery growth of Pterocarpus erinaceus hulled seeds. To this end, four pre-treatments were applied to Pterocarpus erinaceus hulled seeds to lift their dormancy in order to facilitate germination of the species. These were: untreated seeds as Control (To), soaking in ordinary water for 24 h (T1), soaking in hot water at 60°C (T2) and soaking in sulfuric acid (H2SO4) for 20 min (T3). Germination parameters such as germination rate, germination time and average germination time were evaluated. Growth in height, diameter, number of leaves and root length were determined. Germination data and growth parameters were collected. Analyses showed that soaking shelled seeds in ordinary water for 24 h was the best treatment, with a germination rate of 43%. Pre-treatment of the seeds with sulfuric acid for 20 min showed the lowest germination rate (1%), due to the sensitivity of the seeds. Furthermore, these pre-treatments had no effect on seedling growth in the nursery. Those interested in producing Pterocarpus erinaceus seedlings are advised to soak shelled seeds in ordinary water for 24 hours to ensure better germination in the nursery.

Effective pretreatment of microwave combined with acetic acid soaking on oil absorption and quality of fried potato chips.

This study applied a combined pretreatment method involving microwave and acetic acid (AA) soaking to monitor oil absorption of fried potato chips based on texture and microstructure characteristics. Results demonstrated that medium-low microwave combined with 4 h of AA soaking significantly improved the texture profile of potato chips, and reduced oil content by approximately 53.25%. Higher microwave intensity led to greater surface roughness of samples, whereas AA soaking for 1-4 h effectively reduced surface roughness. The decrease in Fm and Nwr, along with the increase in Fwr and Wc with prolonged AA soaking time for 1-4 h indicated that medium-low microwave intensity combined with AA pretreatment enhanced hardness and brittleness of samples. Microscopic examination of cell structure revealed that this combined pretreatment facilitated pectin gelation between the cell walls of potato chips, resulting in a more intact cell structure with fewer gaps. Additionally, the color of pretreated potato chips became brighter. The combination of medium-low microwave intensity and AA soaking pretreatment resulted in a decrease in the oil content and improved the texture profile of fried potato chips. This study provides new strategies and insights for producing low-fat potato chips based on low-cost pretreatment. © 2024 Society of Chemical Industry.

Polypropylene Blends with Durable Hydrophobicity and Enhanced Mechanical Properties Based on POSS and Alkane Modified Polypentafluorophenyl Methacrylate.

Durable functionalization on polypropylene (PP) surfaces is always a key problem to besolved. Coatings with low surface energy peel off easily especially under extreme conditions, owing to their weak adhesion. In this paper, side groups of both polyhedral oligomeric silsesquioxane (POSS) and alkane are grafted to polypentafluorophenyl methacrylate (PFP), and then PP blends with these side-group modified PFP are obtained through a melt-blending process. It is found that POSS can result in surface segregation and provide hydrophobicity in blends. Microfibers are formed because of the orientation effect during the tensile testing, which furtherly promotes mechanical strength. Significantly, alkaneside-groups can be entangled with PP segments, which brings about cross linking. Therefore, with crosslinking and synchronous orientation of POSS, the elongation at the break of blends is greatly increased up to 974%. The final blend demonstrates quite durable hydrophobicity under many extreme conditions, such as repeated tape peeling, ultrasonic washing, strong friction, and soaking in strong acid (pH = 1), strong alkali (pH = 14) and alcohol. The heat and UV resistance of the blend are also obviously improved. This study will develop anovel and facile strategy to endow PP with durable hydrophobicity as well as greatly enhanced mechanical properties.

Effect of acid soak treatment of the precursor on the structure and properties of polypropylene-based carbon fibers

Polyolefin fibers have received wide attention as the precursor for low-cost carbon fiber, and cross-linking of linear polyolefin by strong acid has been proven to be an effective way to stabilize the precursor fiber prior to carbonization. However, the conventional temperature used in sulfonation process is too high and could result in severe decomposition of the linear chain of the polymer, which further deteriorated the mechanical properties of the as-prepared carbon fiber. Thus, reducing the duration of sulfonation process operated at high temperature may alleviate the degradation behavior, conferring the polyolefin-based carbon fibers with better performance. In this paper, polypropylene (PP) fibers were soaked in sulfuric acid at 50 °C–90 °C, before the conventional preparation protocol of PP-based carbon fiber. The structural evolution from PP to carbon fiber were characterized by Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Raman spectroscopy. The mechanical and conductive properties of carbonized fibers where further measured. The results showed that the soak in sulfuric acid resulted in swelling of PP fibers in diameter direction, as well as reducing the crystallinity of the fibers, both of which were physical transformation, and could be easily controlled by soak temperature. The subsequent sulfonation at conventional temperature was fastened for the soaked PP fibers, and the duration of sufficient sulfonation were almost reduced by half. The obtained carbon fibers exhibited better thermal conductivity and mechanical properties, which were enhanced by 25 % and 40 %, respectively, compared with that without soak pretreatment.

Effect of calcium chloride blanching combined with acetic acid soaking pretreatment on oil absorption of fried potato chips

This study investigated the effect of calcium chloride (CaCl2) combined with acetic acid (AA) pretreatment on the oil absorption of potato chips and explored the possible mechanisms influencing oil absorption. Results indicated that compared with hot water blanching, the combination of 0.3% CaCl2 blanching and AA soaking for 2–8 h pretreatment was found to reduce oil content by 10.52%–12.68% and significantly improve the crispness and color of fried potato chips. Microstructural and textural analyses revealed that the main reason for the reduction in oil content was the promotion of pectin gelation in the cell wall by CaCl2 and AA. However, it was observed that prolonged AA soaking time and high-concentration CaCl2 blanching led to an increase in total oil content and decrease in brittleness. Based on the results of surface roughness and moisture content analyses, it was suggested that the CaCl2 and AA pretreatments affected surface roughness and moisture content, thereby increasing oil absorption and reducing brittleness during frying.

Germination of Senegalia mellifera seeds in response to presowing treatments

This study aimed to evaluate the size of Senegalia mellifera seeds and determine the most effective scarification techniques to improve germination. The experiment, conducted at Botswana University of Agriculture and Natural Resources, involved ten presowing treatments, including control, nicking, soaking in sulphuric acid for different durations, and boiling water for varying periods. A completely randomized design (CRD) was used for the experiment. Germination data was transformed using arcsine to meet normal distribution requirements and then analyzed using analysis of variance (ANOVA). The results showed that the presowing treatments had a statistically significant effect on germination (P<0.00001). Seeds treated with sulphuric acid, nicking, and those left untreated exhibited the highest germination rates, while seeds treated with boiling water showed the lowest germination percentages. These findings indicate that the seed coats of S. mellifera are permeable to water and air, and presowing treatments do not show any significant effect on the successful germination of S. mellifera seed.

Seed dormancy types and germination response of 15 plant species in temperate montane peatlands.

Despite their crucial role in determining the fate of seeds, the type and breaking mode of seed dormancy in peatland plants in temperate Asia with a continental monsoon climate are rarely known. Fifteen common peatland plant species were used to test their seed germination response to various dormancy-breaking treatments, including dry storage (D), gibberellin acid soaking (GA), cold stratification (CS), warm followed cold stratification (WCS), GA soaking + cold stratification (GA + CS) and GA soaking + warm followed cold stratification (GA + WCS). Germination experiment, viability and imbibition test, and morphological observation of embryos were conducted. Of the 15 species, nine showed physiological dormancy (PD), with non-deep PD being the dominant type. Four species, Angelica pubescens, Cicuta virosa, Iris laevigata, and Iris setosa exhibited morphophysiological dormancy. Two species, Lycopus uniflorus and Spiraea salicifolia, demonstrated nondormancy. Overall, the effect hierarchy of dormancy-breaking is: CS > GA > WCS > GA + CS > D > GA + WCS. Principal component analysis demonstrated that seed traits, including embryo length: seed length ratio, seed size, and monocot/eudicot divergence, are more likely to influence seed dormancy than environmental factors. Our study suggests that nearly 90% of the tested peatland plant species in the Changbai Mountains demonstrated seed dormancy, and seed traits (e.g. embryo-to-seed ratio and seed size) and abiotic environmental factors (e.g. pH and temperature seasonality) are related to germination behavior, suggesting seed dormancy being a common adaptation strategy for the peatland plants in the temperate montane environment.

One-step facile pathway synthesis of PAPXD/1214-PEA thermoplastic elastomer: Structure and properties

In this study, a novel and facile one-step synthesis route was conducted to prepare semi-aromatic polyamide elastomer (PAPXD/1214-PEA) with p-phenylenediamine, dodecane diamine, dodecanedioic acid and polyether amine (PEA) as monomers. A systematic investigation has been conducted into the effect of hard segment content on the thermal, mechanical and solvent resistance of polymers when semi-aromatic polyamides are used as hard segments. It was found that the melting point of the copolymers gradually increased from 191.2 °C to 231.5 °C with the hard segment content increased from 39 % to 76 %, while the Vicat softening temperature (VST) enhanced from 103.2 °C to 192.2 °C. Compared with the commercial polyamide elastomer Pebax@ (produced by Arkema Inc) with similar hard segment contents, the VST of PAPXD14/1214-PEA were 17.4–66.2 °C higher. The mechanical performance of these elastomers was also largely improved with tensile strength increasing from 15.1 to 40.6 MPa, Young's modulus from 28.2 to 168.7 MPa, toughness from 91.1 to 170.7 MJ/m3. In addition, the solvent resistance properties of PAPXD14/1214-PEA was compared with the commercial polyamide elastomer Pebax@. After soaking in hydrochloric acid for 24 h, the tensile strength of PAPXD/1214-PEA with the hard segment content increased from 50 % to 63 % decreased down to 9.4 and 14.4 MPa, respectively. While the commercial polyamide elastomer Pebax@ (with similar hard segment content) decreased down to 1.5 and 4.3 MPa, indicating the commercial polyamide elastomer products were deteriorated. This suggests the corrosion resistance of the synthesized PAPXD/1214-PEA is much better than that of commercial product, and these semi-aromatic polyamide elastomers can be potentially applied in some harsh service environment especially for high temperature and corrosion sealing.

Effect of low-frequency ultrasound-assisted acid extraction on gel properties and structural characterization of sheep's hoof gelatin

In this study, we investigated the effects of various low-frequency ultrasound-assisted extraction processes, including ultrasound-assisted acid-soaked water bath extraction (UAW), ultrasound-assisted water bath extraction after acid soaking (AUW), acid-soaked water bath extraction followed by ultrasonics (AWU), and acid-soaked water bath extraction without ultrasound (CON), on the structural properties, thermal stability, gel properties, and microstructure of sheep's hoof gelatin. The results revealed that the primary components of sheep's hoof gelatin consisted of α1-chain, α2-chain (100–135 kDa), and β-chain. In addition, it was observed that among the three sonication groups, sheep's hoof gelatin extracted in the AUW group exhibited the highest yield (27.16 ± 0.41 %), the best gel strength (378.55 ± 7.34 g), and higher viscosity at the same shear rate. The gelling temperature (25.38 ± 0.45 °C) and melting temperature (32.28 ± 0.52 °C) of sheep's hoof gelatin in the AUW group were significantly higher than those in the other groups (p > 0.05). Moreover, our experiments revealed that the sequence of low-frequency ultrasonic pretreatment processes was a crucial factor influencing the gel properties and structural characteristics of sheep's hoof gelatin. Specifically, the acid treatment followed by the ultrasound-assisted approach in the AUW group yielded high-quality and high-yield sheep's hoof gelatin.

Sustainable approach for seed stimulating and sowing date to enhance field emergence and growth of sorghum (Sorghum bicolor L. Moench)

Sorghum cultivation is often accompanied by low field emergence rates and weak seedlings, which may be due to genetic or environmental stress. A factorial experiment was conducted in the spring and fall seasons of 2022 using a randomized complete block design with split-plot arrangement and four replications. Planting dates (spring season: Feb. 15th, Mar. 1st, 15th, and Apr. 1st, 15th; fall season: Jun. 15th, Jul. 1st, 15th, and Aug. 1st, 15th) were allocated to the main plots. Seeds stimulation treatments (35% banana peel extract + 100 mg L−1 citric acid and distilled water soaking treatment only) were allocated to the subplots. The interaction treatment (banana peel extract + citric acid) with the planting date of April 15 showed the highest field emergence (74.2%), 75% flowering (86.0 day), plant height (163.9 cm), and days to physiological and complete maturity (111.0 and 131.0 day), respectively. The banana peel extract + citric acid soaking treatment with the planting date of July 1st showed the highest field emergence (91.3%), plant height (185.1 cm), leaf area index (7.6), and dry weight per plant (398.8 g). It can be concluded that the seeds primed with banana peel extract + citric acid before planting improved growth characteristics and could be a solution to environmental challenges, which also promote the concept of sustainable agriculture. It can be recommended seeds soaking with a combination of banana peel extract and citric acid to enhance emergence and growth when planting in April 15th for the spring season and July 1st for the fall season.

Highly efficient nanocellulose adsorbents

Adapting the use of nanocellulose as a sorbent is currently considered an extremely pressing problem, as synthetic analogues, although perform their functions well, are often toxic and incapable of biodegradation. In addition, the production of such synthetic sorbents is quite expensive. Therefore, today the production and modification of nanocellulose in order to increase their absorption capacity is especially important. Furthermore, a number of new applications of nanocellulose have been presented in nanocomposites, Pickering emulsions, wood adhesives, wastewater treatment, and emerging biomedical technologies. The problems and possibilities of new materials based on nanocellulose are being actively discussed. In the course of this work, a composite based on nanocrystalline cellulose from buckwheat, characterized by high sorption properties, environmental safety, and low cost of production, was obtained. Modification of cellulose was carried out with lactic acid. Nine groups of nanocrystalline cellulose samples with different acid soaking times were synthesized, and the optimal time required for the complete grafting of the acid into cellulose was determined. The specific surface area of the composite material was calculated using the Congo red dye adsorption method. It has been found that the specific surface area of the modified composite is not inferior to the specific surface area of many synthetic adsorbents, and even surpasses them in terms of environmental and economic indicators.

Variations in Seed Dormancy Occurrence and Their Classifications in Thirteen Actinidia Species

As differences in seed dormancy between Actinidia species have not been reported previously, in this study we characterized the variation in the dormancy of seeds in 13 kiwifruit species that originated from different regions of China and Taiwan, and for which mature plants are now growing in New Zealand orchards. Dormancy-breaking treatments, including cold-moist stratification, seed coat scarification and soaking in water and gibberellic acid (GA3), were tested for their efficacy in alleviating dormancy and improving final germination and germination rates. In addition, we assessed seed viability using RNA integrity analysis to distinguish dead seeds from dormant seeds. This study identified that dormancy type in Actinidia seeds is species-specific and can be morphological, morphophysiological or a combination of physiological and physical, and that seed RNA integrity is a useful metric to incorporate into seed dormancy studies. Our results also suggest that species originating from colder climates that experience large differences between winter minimum and summer maximum temperatures exhibit physiological dormancy and require cold-moist stratification, contrasting with species originating in milder climates. Interestingly, although not all seeds from all the species were dormant, the proportion of dormant seeds in each species did not correlate to the climatic data of the region from which they originated. These findings provide new insights into mechanisms of seed dormancy in kiwifruit.

Impact of Pre-drying Treatments on Antioxidant Activities and Quality of Dried Golden Oyster Mushroom (Pleurotus citrinopileatus)

The effects of three pre-drying treatments including blanching in hot water (60oC-70oC for 3 and 5 min), soaking in NaCl (1-4% w/v for 10 and 20 min), and soaking in citric acid (0.2-0.8% w/v for 10 and 20 min) on dried Golden oyster mushroom (GOM) were studied. Color values (L*, a*, and b*), browning index (BI), polyphenol oxidase (PPO) activity, protein content, flavonoid content (FC), total phenolic content (TPC), and antioxidant activities (metal chelating activity and DPPH radical scavenging activity) of dried mushrooms were evaluated. All pretreated mushrooms had significantly higher lightness (L*) and lower a* and b* values compared to those of un-pretreated ones. Decreases in BI and PPO activity were observed in pretreated mushrooms. Higher blanching temperatures, concentrations of NaCl and citric acid, and time yielded lower protein content, TPC, and FC. Among the pretreatments, the highest antioxidant activities were observed in citric acid treated GOM. Thus, blanching and chemical pretreatments could enhance the lightness and lower BI of dried GOM, although they lowered the nutrient levels and antioxidant activities of the dried GOM.

Rutting Prediction of Asphalt Mixtures Containing Treated and Untreated Recycled Concrete Aggregate

Rutting is a crucial element of the mechanical performance characteristics of asphalt mixtures, which was the primary target of this study. The task involved substituting various portions of virgin coarse aggregate with recycled concrete aggregate materials that had been treated or left untreated at rates ranging from 25 to 100%, with a constant increase of 25%. The treatment process of recycled concrete aggregate involved soaking in acetic acid, followed by a mechanical process for a short time inside a Los Angeles machine without the balls. This research utilized two primary tests: the standard Marshall test to identify the optimal asphalt contents and the volumetric characteristics of asphalt mixtures. The other one was the wheel tracking test, which involved manufacturing 11 slabs with a dimension of 30 x 40 × 5 cm and testing them under repeated wheel loads of 700 N at 55°C to investigate rutting resistance. The results demonstrate that using RCA had a negative impact on rutting resistance, where rut depth increased by 21.64% when using 100% pre-soaked treated RCA.

Effects of Edible Organic Acid Soaking on Color, Protein Physicochemical, and Digestion Characteristics of Ready-to-Eat Shrimp upon Processing and Sterilization

Soft-packed ready-to-eat (RTE) shrimp has gradually become popular with consumers due to its portability and deliciousness. However, the browning caused by high-temperature sterilization is a non-negligible disadvantage affecting sensory quality. RTE shrimp is processed through “boiling + vacuum soft packing + high temperature and pressure sterilization”. Ultraviolet-visible (UV) spectroscopy with CIELAB color measurement showed that phytic acid (PA) + lactic acid (LA), PA + citric acid (CA), and PA + LA + CA soaking before cooking alleviated browning, as well as UVabsorbance and the browning index (BI). Meanwhile, UV spectroscopy and fluorescence spectroscopy showed that organic acid soaking reduced the content of carbonyl, dityrosine, disulfide bonds, surface hydrophobicity, and protein solubility, but promoted the content of free sulfhydryl and protein aggregation. However, in vitro digestion simulations showed that organic acid soaking unexpectedly inhibited the degree of hydrolysis and protein digestibility. This study provides the basis for the application of organic acids as color protectors for RTE aquatic muscle product.

A robust superhydrophobic coating of SER/ ZnO/MWCNTs with high corrosion resistance was prepared by one-step spraying method

Multifunctional integration is the basic feature of artificial superhydrophobic coatings widely used in many fields. This paper presents a simple and economical experimental method to prepare a super hydrophobic coating with super strong corrosion resistance by spraying a mixed solution composed of epoxy resin (EP) as the base, multi-walled carbon nanotubes (MWCNTs), sericite (SER), nano-zinc oxide (ZnO) and octadecyl trimethoxysilane (ODTMS) on an aluminum substrate. Firstly, the superhydrophobic property of the coating prepared in this experiment is better than that of the ordinary coating, and its contact angle reaches 167.3° and rolling angle is as low as 2.7°. Secondly, the superhydrophobic coating can not only maintain the superhydrophobic property in harsh environment (such as: soaking in boiling water for 10 hours, soaking in acid, alkali and salt solution for 7 days, high temperature, burning and strong ultraviolet irradiation, etc.), but also can withstand a variety of mechanical damage without losing the superhydrophobic property (such as: 1000 sandpaper wear cycles, 100 tape stripping cycles and 1000 g grit sustained impact). In addition, the excellent non-wettability of superhydrophobic coating can make it have excellent performance in the field of selfcleaning and anti-fouling. It is worth mentioning that the electrochemical workstation experiment proved that the coating also has good corrosion resistance, and the anticorrosion efficiency reached 99.924%. This strong superhydrophobic coating has many functions, such as self-cleaning, antifouling and corrosion prevention, and will have good application prospects in many fields in the future.

Breaking seed dormancy in Searsia pentaphylla (Anacardiaceae)

Seeds (true seed plus endocarp) of Searsia pentaphylla, a species with significant medicinal, ecological and horticultural importance, have an extremely hard and water impermeable endocarp. Hence, effective dormancy-breaking techniques are crucial for enhancing its cultivation and ensuring successful establishment in both natural and managed environments. This study evaluated the effects of mechanical scarification, chemical scarification (sulphuric acid soaking for 30, 60, 90 and 120 minutes, hydrogen peroxide soaking for 10 minutes), hot water soaking for 10 minutes, and heat treatment for three minutes at 200°C on final germination percentage (FGP), mean germination time (MGT), time to 50% germination (T50), coefficient of velocity of germination (CVG) and mean daily germination (MDG). Compared to the control group (untreated seeds), the most effective treatment was 120 minutes of sulphuric acid soaking, achieving a FGP of 92%, a MGT of 7.28 days, a CVG of 13.7%, a T50 of 6.67 days and a MDG of 6.57%. Mechanical scarification yielded a FGP of 36.5%, with poorer MGT, CVG, T50 and MDG values. Other methods, including hydrogen peroxide and heat, were less effective. These results highlight the importance of aggressive scarification techniques to enhance germination in S. pentaphylla.

The Influence of Acid and Cooking Methods on The Quality of Fish Meal Processed from by-products of Catfish Fillet Processing

Catfish fillet processing produces a by-product dominated by heads (25- 28%) and bones (11-13%). This study aims to process fish meal from by- products of catfish using different treatments, namely soaking in a 4% formic acid solution (F) and a 4% hydrochloric acid solution (H), as well as cooking techniques involving boiling (R) and steaming (K). Observations were made on the yield, pH, proximate analysis, calcium content, NPN (non-protein nitrogen), TBA (thiobarbituric acid), microbiological tests, sensory evaluation, and amino acid profiles. The research showed that soaking in acid caused a decrease in pH, protein content, and TBA and increased the fat content of the resulting fish meal. The optimal treatment for the highest quality fish meal is steaming without acid treatment. In this treatment, the protein content meet the requirements of the SNI 01.2725.01.2013 as grade 3 fish meal, with a yield of 22.83%, a pH of 6.86, a moisture content of 6.2 ± 0.3%, an ash content of 27.33 ± 0.7%, and a protein content of 45.5 ± 1.3%. Analysis of the amino acid profile of fish meal from that treatment showed a better amino acid composition compared to commercial fish meal. The fish meal contained essential amino acids in sufficient quantities, with higher levels compared to the amino acid standards set by FAO/WHO 2013 for human nutritional needs, and met the requirements as a nutritional ingredient for fish and livestock feed.

Effect of Acid Soaking on Properties of Zeolite-Based Porous Carbon Composite Prepared for Adsorption of Cationic Dye

Effect of Acid Soaking on Properties of Zeolite-Based Porous Carbon Composite Prepared for Adsorption of Cationic Dye