Acid Soaking Research Articles

Germination Biology of Picralima nitida(Stapf) under Pretreatments

Viable seed sometimes fails to germinate under favourable conditions. The study assessed the germination of Picralima nitida (Stapf) seeds following pretreatments. Fruits were collected from Benin, Southern Nigeria (lat. 6 0 23 1 N and long. 5 0 13 1 E). The seeds were extracted manually and processed for sowing. Seeds were pretreated using ten pretreatment methods: control; soaking in water at 90 0 C and allowing to cool overnight; soaking in water at room temperature; seeds which coats were manually removed; soaking in concentrated sulphuric acid (H 2SO 4) for 1min; 2mins; and 5mins; and soaking in primarily recycled H 2SO 4 for 2mins, 5mins and 10mins. One hundred seeds were assigned to each treatment and replicated in two locations of Akungba (lat. 7 0 28 1 N and long. 5 0 46 1 E) and Ibadan (lat. 7 0 24 1 N and long. 3 0 49 1 E). Seeds were sown in germination trays containing washed-sterilized river sand in the screen house. Germination counts were taken daily. P. nitida exhibited “durian-epigeal” germination, seeds which coats were manually removed were the first batch to germinate 17 and 22 days after sowing (DAS) in Ibadan and Akungba respectively. The highest germination percentage of 100 in Ibadan and 84 in Akungba were obtained among this batch. Seeds soaked in water at room temperature gave 86% germination in Akungba and 63% in Ibadan. Seeds soaked in water at 90 0 C, and primarily recycled H2SO 4 acid for 10mins did not germinate for 106days. Analysis of variance revealed significant differences at P ≤0.05 in treatment and location effects. Mean germination percentage of seeds which coats were removed was significantly different from other treatments. The inherent dormancy in P. nitida seed can be treated by manually removing the seed coat before sowing.

The Research on the Adsorptive Capability and Adsorption Isotherm of Modified Talcum Powder to Methylene Blue

The preparation conditions of modified talcum powder were investigated by discuss the effects of nitric acid mass concentration, nitric acid soak temperature, roasting temperature and roasting time on adsorption properties of methylene blue by talcum powder. Methylene blue dye, as target pollutant, exhibits difficult biochemical degradable characters. The adsorption isotherm of adsorption process was discussed by using the Langmuir isotherm model and Freundlich isotherms model. The results show that the rate of adsorption of methylene blue decreased with the increasing of roasting temperatures and nitric acid soak temperature of modificated talcum powder. The adsorption value of methylene blue of the modified talcum powder increased gradually，then decreased with the increase of roasting time. Compare with the unmodified talcum powder，the adsorption value of methylene blue of the modified talcum powder decreased when roasting temperature and roasting time is too high. With the nitric acid mass concentration increasing, the adsorption of methylene blue on the modified talcum powder increased. It is found that the adsorptive ability of modified talcum powder by HNO3 is higher than original talcum powder. The best talcum powder modified preparation condition is that nitric acid mass concentration 50%, the nitric acid soaks temperature 40°C, calcined temperature 200°C for 120 mins. The removal rate of methylene blue is 84.6% under these preparation conditions. The experimental date fitted very well with the Langmuir isotherms model.

Effects of various pretreatments and drying methods on Salmonella resistance and physical properties of cabbage

The combined effects of pretreatment and drying methods on the resistance of Salmonella attached to vegetable surfaces as well as some physical properties, in terms of color and shrinkage, were investigated. Cabbage was used as a test vegetable and Salmonella Anatum was used as a test microorganism. Cabbage leaves were pretreated either by soaking in 0.5% (v/v) acetic acid for 5min, blanching in hot water for 4min or blanching with saturated steam for 2min prior to either hot air drying, vacuum drying (10kPa) or low-pressure superheated steam drying (10kPa) at 60°C. Based on an initial Salmonella contamination level of approximately 6.4logCFU/g, soaking in acetic acid, hot-water and steam blanching resulted in 1.6, 3.8 and 3.6logCFU/g reduction in the number of Salmonella, respectively. Drying without pretreatment could not completely eliminate Salmonella attached on the cabbage surfaces, while no Salmonella was detected on the pretreated samples at the end of the drying process. Volumetric shrinkage was not affected by the pretreatment and drying methods. Dried blanched samples exhibited greener and darker color than the dried acetic acid pretreated and untreated samples.

Structural modification by different pretreatment methods to enhance microwave-assisted extraction of β-carotene from carrots

Since the structure of a material is a key factor influencing the extraction efficiency, any means to modify the structure to enhance extraction is attractive. As limited information is available on the effect of sample pretreatment prior to extraction on the extractability of a bioactive compound, the effects of selected pretreatment methods, i.e., soaking in citric acid, blanching in water as well as in citric acid, on the sample structure and subsequent microwave-assisted extraction (MAE) were investigated; carrots and β-carotene (as well as carotenoids) were selected as the test material and bioactive compound, respectively. A suitable condition to extract β-carotene in terms of the microwave power and extraction time was determined. Comparison between MAE and Soxhlet extraction was also made. At the optimized condition the contents of β-carotene and total carotenoids extractable from carrots blanched in water (29.74 and 58.04mg/100g dry basis) and in citric acid (32.08 and 61.62mg/100g dry basis) were significantly higher than those from the untreated carrots (23.26 and 51.79mg/100g dry basis). The antioxidant activities of the extracts obtained from carrots blanched in water and in citric acid were also higher than that from carrots with no pretreatment. Comparison between MAE and Soxhlet extraction revealed that the extract from MAE contained lower amounts of β-carotene and total carotenoids and exhibited lower antioxidant activity; the required MAE time was significantly shorter, however.

Thin-film composite nanofiltration membranes with improved acid stability prepared from naphthalene-1,3,6-trisulfonylchloride (NTSC) and trimesoyl chloride (TMC)

Thin-film composite (TFC) nanofiltration (NF) membranes with improved acid stability were fabricated through the interfacial polymerization of trimesoyl chloride (TMC) naphthalene-1,3,6-trisulfonylchloride (NTSC), and piperazine (PIP) on a porous polysulfone support membrane by varying the NTSC content in TMC-organic solution. The physico-chemical characteristics of the membranes were analyzed by ATR-FTIR, streaming potential measurement and surface contact angle measurement, the permeation properties were evaluated through cross-flow permeation tests, and the acid stability was investigated through both static acid soaking tests and long-term permeation tests under acidic condition. It was found that, as the NTSC content in TMC-organic solution increased, the membrane surface became more hydrophilic and negatively charged, the pure water permeability and molecular weight cut-off of the formed NF membrane increased from 5.5 to 10.6l/m2hbar and about 360 to 660Da, respectively, while the rejection rate to Na2SO4 firstly increased from 98.2 to 98.7% and then declined to a lower value of 97.8%. After soaking in 8w/v% H2SO4 for 30days or filtration with 4.9w/v% H2SO4 for 60days, the TFC membranes prepared from TMC and NTSC showed little performance change, while serious performance deterioration occurred with the TFC membrane prepared from TMC.

Optimization of levulinic acid production from Gelidium amansii

The study of bioproduct production, such as bioethanol and biochemicals, from inexpensive biomass has recently attracted considerable attention. Compared to land biomass, marine biomass can be grown rapidly and is easily cultivated without the need for expensive equipment. In addition, annual CO2 absorption by marine biomass is five to seven times higher than that of wood-biomass and the carbohydrate content is higher and can easily be converted to chemicals through proper chemical processes. In the production of various biochemicals from marine biomass, levulinic acid is a highly versatile chemical with numerous industrial uses and the potential to become a commodity chemical. It can be used as a raw material for resins, plasticizers, textiles, animal feed, coatings and antifreeze. The present study was carried out to determine the optimum conditions of temperature, acid concentration and reaction time for levulinic acid production from marine biomass Gelidium amansii using two-step treatment. In the first hydrolysis step, solid-state cellulose was obtained through acid soaking and used to produce ethanol by fermentation and liquid-state galactose. In the second hydrolysis step, the liquid-state galactose was converted into levulinic acid via a high-temperature reaction in a batch reactor. The overall production conversion of G. amansii biomass to levulinic acid in the two-step acid hydrolysis was approximately 20.6%.

Superação da dormência de sementes de Cupressuslusitanica Mill

Cupressuslusitanica Mill.is a multipurpose tree species with a high potential for wood production in Brazil. The main objective was to evaluate methods to dormancy break to promote seed germinationin C. lusitanica. The following treatments were used: T1 (intact seeds); T2 (soaking in water for 24 hours); T3 (soaking in water for 36 hours); T4 (stratification on 4 °C for 30 days); T5 (immersion in water for 8 hours + stratification on 4 °C for 30 days); T6 (immersion in water for 8 hours + stratification on 4 °C for 20 days); T7 (immersion for 12 hours + stratification on 4 °C for 20 days); T8 (soaking in hot water at 80ºC for 5 minutes); T9 (sulfuric acid soaking for 5 minutes). It was evaluated the percentage and germination speed (IVG). The resultsweresubmitted to ANOVA andmeanswere comparedusingthe Skott-Knott. The treatments T5, T2 and T7 showedhighergermination, and T7 higherspeedofgermination, thesecanberecommended for overcomingseeddormancyof C. lusitanica.

Seed germination and seedling vigour as influenced by pregermination seed treatment in Himalayan Dogwood (Benthamidia capitata Wall ex. Roxb.)

Influence of different treatments on seed germination and seedling vigour of Benthamidia capitata, involving water soaking (8, 16, 24, 32, 40, and 48 h), gibberellic acid soaking (100, 200, 300, 400, 500, and 600 mg− 1), and sulphuric acid scarification (3, 6, 9, 12, 15, and 18 min), was studied to identify the best responding presowing seed treatments. The greater seed germination, root, shoot, and seedling length, along with vigour index, were observed for 32 h water soaking, while 300 mg− 1 of GA3 treatment gave maximum seed germination and seedling vigour. However, seed treated in sulphuric acid for 6 min produced the maximum number of elite seedlings. Among the pretreatments, sulphuric acid was found to be the most effective scarifying agent for breaking physical seed dormancy, but the risk associated with the handling of acid for both seeds and humans requires consideration. In this context, water soaking for 32 h appears to be the most promising method for nursery growers as it is eco-friendly, economical, and easy to apply.

Preparation and characterisation of aluminium pigments encapsulated by composite layer containing organic silane acrylate resin and SiO2

PurposeThe purpose of this paper is to enhance the anticorrosion property of aluminium pigments and to improve their compatibility with polymers in coating.Design/methodology/approachAluminium pigments encapsulated by organic‐inorganic layer were prepared by hydrolysis and condensation of organic silane acrylate resin and tetraethoxy silane (TEOS) on the surface of pigments via sol‐gel method. TEOS and poly (methyl methacryalte‐n‐butyl acrylate‐vinyl triethoxysilane) (PMBV) formed in advance by co‐polymerisation of methyl methacrylate (MMA), n‐butyl acrylate (BA) and vinyl triethoxysilane (VTES) were used as precursors. The adhesion property of the aluminium pigments was measured by peel test, and the loss of silvery appearance after encapsulation and acid soaking were both evaluated by colour lightness difference (ΔL) measurement. The encapsulated aluminium pigments were further characterised by means of FTIR, SEM, TG and XPS.FindingsIt was found that PMBV‐SiO2 thin films could be formed on the surface of aluminium pigments smoothly and uniformly, and the adhesion and anticorrosion performances of encapsulated aluminium pigments were improved significantly.Research limitations/implicationsThe organic silane acrylate resin used as a precursor in the sol‐gel process could be synthesised from other aclyate monomers. In addition, the hydrolysis and condensation mechanism of organic silane acrylate resin on the surface of aluminium pigments need further studies.Practical implicationsThe method developed provided a good solution to the two problems of aluminium pigments and increased their application values.Originality/valueThe method of improving adhesion and anticorrosion properties of aluminium pigments was novel and could find numerous applications in surface coatings and adhesives.

Acid stable thin-film composite membrane for nanofiltration prepared from naphthalene-1,3,6-trisulfonylchloride (NTSC) and piperazine (PIP)

Abstract Acid stable thin-film composite membrane for nanofiltration was fabricated by interfacial polymerization of naphthalene-1,3,6-trisulfonylchloride (NTSC) and piperazine (PIP) on porous polysulfone support membrane. The performance of the membrane was optimized by studying the preparation parameters including monomer content, reaction temperature and additive in organic phase. The separation performance of the resultant membrane was evaluated through permeation experiments, the membrane property was characterized by ATR-FTIR, XPS AFM, SEM and streaming potential measurements, and the acid stability was investigated through both static acid soaking tests and long-term permeation tests under acidic condition. After exposure to 20%(w/v) H2SO4 for 2 months or running with 4.9%(w/v) H2SO4 for 60 day, the PIP-NTSC composite membrane showed minor change in separation performance and no evident chemical change in the active skin layer, indicating that the developed membrane possessed good acid stability. The desired membrane exhibited a pure water permeability of about 5.8 l/m2 h bar, a MWCO of as high as 5000 Da, and an attractive solute rejection of higher than 86.5% for a feed containing 500 mg/l Na2SO4 at 0.5 MPa. Furthermore, the PIP-NTSC composite membrane could be used to treat acidic effluents from metal industries with good perm-selectivity and long-term stability.

Acid Rain Erosion Resistance of Concretes Containing Super-Fine Mineral Admixtures

The sulphuric acid erosion resistance of high strength concretes containing limestone powder,titanium slag and silica ash were studied by accelerating cycle sulphuric acid soak tests. It indicates that the introduction of super-fine mineral powders into concrete can improve its sulphuric acid erosion resistance. With fixed 10% limestone powder, blending 10% titanium slag or 15% silica ash can remarkably enhance sulphuric acid erosion resistance of concrete. The concretes containing mineral admixtures such as limestone powder, titanium slag and silica ash can be used in acid rain abundant area.

Preparation process of a highly resistant wollastonite bioceramics using local raw materials

Wollastonite (CaSiO3) is mainly used for traditional ceramics. In this study, wollastonite-based ceramics was obtained by solid state reaction. The starting powders were sintered at different temperatures (850–1,250 °C) for 2 h. Moreover, different amounts of B2O3 (0.5–5.0 mass%) have been added. A relative density of about 97% of the theoretical was reached for samples sintered at 1,050 °C for 2 h, containing 3 and 5 mass% B2O3. Excellent values of both three point flexural strength (343 ± 34 MPa) and micro-hardness (4.8 GPa) for samples containing 5 mass% B2O3, sintered at 1,050 °C for 2 h. Besides this, a relatively low mass loss ratio has been measured (1.1%) for wollastonite samples containing 5 mass% B2O3, sintered under the same conditions, after soaking in lactic acid for 9 days. Finally, the bioactivity of wollastonite by the possibility of formation of apatite on the surface of wollastonite immersed in simulated body fluid was confirmed.

Effect of previous ascorbic acid treatment on the fatty acid profile of cobia (<i>Rachycentron canadum</i>) fillets during frozen storage

The present research focuses on the nutritional value of the lipid retention associated with frozen cobia ( Rachycentron canadum ). The effect of a previous soaking in an aqueous ascorbic acid (AA) solution on the fatty acid profile of fish fillets during a further frozen storage period (–18 °C) was investigated. Two different AA concentrations were tested (0.25% and 0.50%) and compared to control conditions. As a result of the frozen storage period (up to 6 months), marked decreases were found in the contents of fatty acid groups such as monounsaturated, polyunsaturated and n-3 polyunsaturated, as well as in the n-3/n-6 ratio. However, a preserving effect on such fatty acid parameters could be observed resulting from the previous AA treatment, which was greater when applying the 0.50% AA concentration. Assessment of the polyene index indicated an increased lipid oxidation development during the frozen storage time; this increase was partially inhibited by the previous AA soaking.

Recovery of some valuable elements from lamprophyre dykes in the Abu Rusheid area, Southeastern Desert, Egypt

In the Abu Rusheid area, Southeastern Desert of Egypt, polymineralized (HREEs, U, Zn and Pb) lamprophyre dykes are recently recorded. The lamprophyre dykes cut cataclastic rocks along share zones in NNW-SSE trends. The secondary U-minerals are essentially represented by uranophane, kasolite, torbernite and autunite. Experimental work was carried out on the lamprophyre dykes for the recovery of uranium and other valuable elements (e.g. Zn, Pb and Al) from 50 kg of technological sample. The optimum conditions were: 100 g/L sulfuric acid concentration, 1:5 S/L (solid/liquid) and soaking for 15 days at room temperature. The leaching efficiencies for the recovery of uranium and other elements like Al, Zn and Pb were 40, 33.6, 98.8 and 78, respectively.

Preparation of Super-Hydrophobic Aluminum by a Novel Immersion Method using Potassium Permanganate Solutions

A simple method of acid etching and surface passivation was developed for fabricating the super-hydrophobic surface on polycrystalline aluminum alloy. After the chemical etched surface was fabricated with the stearic-acid, the aluminum alloy surface exhibits a super-hydrophobic property with water contact angle of 151°and contact angle hysteresis of 8°. The surface morphology was inspected with scanning electron microscope, and it was found that the surface is configured in a labyrinthic porous structure with plateaus and caves of micro-nanostructure. The air cushion was formed in the caves between the surfaces. This micro-nano hierarchical structure plays an important role in the formation of the super-hydrophobicity. The super-hydrophobic phenomenon of the prepared surface was analyzed with Cassie theory, and the result shows that only about 16% of the water contact surface are contacted with the metal substrate and the rest 84% is contacted with the air cushion. The experimental results showed that aluminum of super-hydrophobic surface can be prepared by this simple method, the optimum process conditions found are after grinding, ethanol soaking,acetic acid soaking sixty hours, immersing in the 0.1mol/L potassium permanganate three hours after soaking and finally immersion in 1% stearic-acid for 30minutes.

In vitro bioaccessibility of β‐carotene in dried carrots pretreated by different methods

SummaryThe effects of selected pretreatment methods, i.e. soaking in citric acid, blanching in water and blanching in citric acid, as well as hot‐air drying (at 70, 80 and 90 °C), on the retention and relative in vitro bioaccessibility of β‐carotene in dried carrots were investigated. The results indicated that the selected pretreatments and drying could enhance the relative bioaccessibility of β‐carotene in dried carrots. The relative bioaccessibility of β‐carotene in dried carrots increased to 47–73%, while the values in the fresh (13%) and dried untreated (31–47%) carrots were lower. Although significant losses of β‐carotene occurred during both the pretreatment and drying processes, bioaccessible β‐carotene contents of dried pretreated carrots were in a similar order to those of the fresh carrots, indicating the ability and hence the benefit of appropriate pretreatment and drying processes in maintaining the nutritive quality of a food product.

The effect of pre-sowing treatments and light on seed germination of Dracocephalum kotschyi Boiss: An endangered medicinal plant in Iran

The aim of this study was to investigate the effect of pre-sowing treatments and light on Dracocephalum kotschyi Bioss. seed germination. The following treatments were used: sandpaper; 3, 5 and 10 min soaking in sulfuric acid; 15 min in sodium hypochlorite; 24 h in water, hot water and boiling water; 50, 150, and 250 mg·L−1 of Gibberellic acid; 1000, 2000, 4000, and 6000 mg·L−1 of KNO3, and water (control). The germination rate, germination start (GS), mean germination time (MGT), time to 50% germination (T50) and cumulative germination were determined as germination indices. Root, shoot and seedling length and the vigor index (VI) were evaluated as growth factors at the end of the incubation period. Second experiment was carried out to study the effect of light on seed germination. It was observed that both the physical and chemical scarification methods were effective in enhancing D. Kotschyi seed germination and growth. In the first stage, up to day 20 SA (10 min) and sandpaper scarification treated seed had shown germination more than 70% whereas control seeds did not begin germination until day 20. The highest germination rate was observed with sandpaper (1.77 units) and SA (1.56 units) in compare with other treatments (less than 0.9 units). Also the highest vigor index was found in SA- and sandpaper-treated seeds and the lowest occurred in sodium hypochlorite treatments. The other results showed that light was more effective than darkness for seed germination.

SO42−/ZrO2–titania nanotubes as efficient solid superacid catalysts for selective mononitration of toluene

SO42 −/ZrO2–titania nanotubes–X (SO42 −/ZrO2–TNTs–X; X of Ti/Zr) solid superacid catalysts with different atom ratios (Ti/Zr) were successfully prepared. The SO42 −/ZrO2–TNTs–2 (Ti/Zr of 2) have a specific surface area of 394 m2/g and an acid intensity of 1.839 mmol/g. The SO42 −/ZrO2–TNTs–2 show excellent selectivity (p/o of 3.34) and activity (yield of 98%) in the selective mononitration of toluene. Importantly, the SO42 −/ZrO2–TNTs–2 can be efficiently recycled and regenerated by simple sulfuric acid soaking.

Methods to overcome of the dormancy in murici (Byrsonima verbascifolia Rich) seeds

The great agricultural development in the Brazilian savannah brought with it the reduction of its natural vegetation, which has been quickly lost, especially due to extractive exploitation by man. Murici ( Byrsonima verbascifolia Rich) is a fruit bearing plant of great medicinal importance in the savannah; however, its propagation is hindered by the fact that the seeds have low germination and seedling emergence in the field is slow. This study evaluated the effect of different dormancy breakage methods in murici seeds. Therefore, were evaluated effect of different temperatures; soaking in gibberellic acid and water; chemical and mechanical scarification and two types of substrate (distilled water and KNO 3 ). Treatments were arranged in a randomized block design. Records made daily on the number of germinated seeds were used to determine the germination percentage and germination speed index. Among the methods evaluated, giberellic acid at 2,309.46 ?M gave the greatest seed germination percentage, especially when the germination paper was moistened with KNO 3 .

Effect of seed size and pre-treatment methods of Bauhinia thonningii Schum. on germination and seedling growth

soaking in potassium nitrate (0.2%) for 10 min and soaking in concentrated hydrochloric acid (0.3 M) for 5 min, and a control where seeds were sown without any treatment. The results showed that the combination of nicking and large seeds produced the highest (100%) germination and highest height and diameter growth. Hot water treatment was also observed to be effective in both seed sizes producing 40 and 53.3% germination for small and large seeds, respectively. The increased seed germination and height for physically scarified seeds through nicking suggest that seed dormancy in B. thonningii is mainly due to relatively hard seed coat which renders the seed testa impermeable to water and gases required for germination process.