Sodium Hydroxide Treatment Research Articles

Adsorption of Pb(II) from aqueous solution using alkaline-treated natural zeolite: Process optimization analysis

• Alkaline-treated zeolite was successfully prepared and applied for Pb(II) removal. • Factors influenced Pb(II) removal, Y : pH, X 2 > adsorbent dosage, X 3 > initial concentration, X 1. • Optimum conditions: X 1 = 240 mg/L, X 2 = 6, and X 3 = 1.07 g/L , Y = 60.75% • Alkaline-treated zeolite showed good regeneration and reusability up to 3 cycles. Alkaline-treated natural zeolite was prepared by sodium hydroxide treatment of natural zeolite and applied in the adsorption of Pb(II). The response surface methodology (RSM) analysis was conducted under manipulated variables of initial concentration ( X 1 = 50-400 mg/L), pH ( X 2 = 2-10), and adsorbent dosage ( X 3 = 0.5-5.0 g/L). The optimal condition was attained at X 1 = 240 mg/L, X 2 = 6, and X 3 = 1.07 g/L, with Pb(II) removal of 60.75%. The characterization of alkaline-treated natural zeolite of fresh and spent confirmed the adsorption of Pb(II) onto alkaline-treated natural zeolite. The reusability and regeneration experiments revealed the ability of the alkaline-treated natural zeolite in multiple cycles of the adsorption process. This study proved that alkaline-treated natural zeolite could be an alternative low-cost adsorbent for wastewater treatment containing Pb(II).

The structural and functional properties of dietary fibre extracts obtained from highland barley bran through different steam explosion-assisted treatments

The effects of steam explosion (SE)-assisted ultrasound (SEU), citric acid (SEC), sodium hydroxide (SEA), and cellulase (SEE) treatment on the properties of soluble dietary fibre (SDFP) extracted from highland barley bran were analysed. The results showed that SE pretreatment combined with other methods effectively improves the SDFP yield. The highest yield of SDF (20.01%) was obtained through SEA treatment. SEU-SDFP had a loose and porous structure, whereas the surface of SEC-SDFP and SEA-SDFP presented a complicated and dense texture. Although SE pretreatment reduced the thermal stability of SDFP, SEC and SEE treatment maintained its thermal stability. Furthermore, SEU-SDFP exhibited the highest water and oil holding capacities, and cholesterol and nitrite ion adsorption capacities. SEE-SDFP exhibited the best DPPH and ABTS radical scavenging abilities. In summary, four SE-assisted extraction methods had different advantages, and highland barley bran SDF can be considered as a potential functional additive in the food industry.

Improving formability of palm leaf materials for foodware manufacturing using sodium hydroxide treatment

Improving formability of palm leaf materials for foodware manufacturing using sodium hydroxide treatment

Comparative Investigation of the Corrosion Behavior and Biocompatibility of the Different Chemical Conversion Coatings on the Magnesium Alloy Surfaces

Due to their good biodegradability and biocompatibility, magnesium alloys are widely favored as the potential candidate for the biodegradable cardiovascular stent. However, the rapid degradation and the limited biocompatibility in vivo remain the main bottlenecks that inhibit their clinical applications. The construction of the chemical conversion coating on the magnesium alloy surface represents one of the effective strategies to control the degradation rate and enhance the biocompatibility. In the present study, the different chemical conversion layers were prepared on the magnesium alloy surface by chemical conversion treatment, including sodium hydroxide (NaOH), hydrofluoric acid (HF), phosphoric acid (H3PO4) and phytic acid (C6H18O24P6) treatment, and the corrosion behaviors and biocompatibility of the chemical conversion layers were comparatively investigated in detail. The results showed that the different chemical treatments can produce the different conversion layers on the magnesium alloy surfaces with a variety of physicochemical characteristics, corrosion resistance and biocompatibility, and all treatments can enhance the corrosion resistance to varying degrees. The hydrophilicity and corrosion resistance of the sodium hydroxide-treated magnesium alloy were the best among all the materials. Although the hydrofluoric acid-treated magnesium alloy had produced a hydrophobic coating, the corrosion resistance still needed to be improved. Magnesium alloys treated by sodium hydroxide showed a selective promotion of albumin adsorption, while the other samples simultaneously promoted albumin and fibrinogen adsorption. For the blood compatibility, the hemolysis rates of all of the treated materials were reduced to below 5%. The samples treated by phytic acid had the smallest hemolysis rate, and the NaOH-treated magnesium alloy had the least amount of platelet adhesion and activation. An appropriate microenvironment for cell growth could be achieved by the chemical conversion treatment, according to the results of the endothelial cell adhesion and proliferation, and the NaOH-treated surface showed the best endothelial cell growth behaviors among all of the samples. In summary, the corrosion resistance and biocompatibility of the magnesium alloy were significantly improved by the sodium hydroxide treatment, and thus this treatment can be used as a pretreatment for the surface modification of the magnesium alloy in order to further enhance the biocompatibility when used as the cardiovascular implants.

Effect of surface modification of polyester fabric on microfiber shedding from household laundry

PurposeSynthetic textile materials are noted as one of the major contributors to microfiber pollution through laundry. Though many research works evaluated microfiber pollution, the solutions provided to control microfiber shedding are meager. The existing products collect or filter the microfiber from laundry effluent and restrict the direct leaching. However, no methods were proposed to effectively reduce the shedding from the textile itself.Design/methodology/approachThis research is aimed to analyze the influence of surface modification of polyester knitted textiles by sodium hydroxide, on microfiber shedding. Response surface methodology was adapted to optimize different treatment parameters (alkali concentration, treatment time and temperature).FindingsThe results show that the sodium hydroxide concentration and treatment time had a negative correlation with microfiber shedding reduction. Whereas, treatment temperature had a positive correlation with microfiber shedding reduction. The statistical analysis revealed that 0.4 M concentration, 90°C temperature and 24 min of treatment time was the best process condition for minimum microfiber release. The same was confirmed with a practical experiment and a significant reduction of 80.63% in microfiber shedding after alkali treatment was found.Originality/valueAlkali treatment of different knitted polyester fabrics with various knit structures and mass per square meter showed a significant reduction in microfiber shedding. The repeated laundry performed for 20 washes with surface-modified samples showed a significant reduction in microfiber release at every wash cycle and ensured the longevity of the effect.

Technical note: Examining the use of ethylenediaminetetraacetic acid for humic extraction of ancient bone

We examined the efficacy of ethylenediaminetetraacetic acid (EDTA) for removing humic contaminants from collagen extracted from ancient bone. Humic contaminants must be removed to obtain reliable stable isotope values from ancient bone collagen, given that humic acids have consistently lower δ13C values than collagen. The purpose of our research was to examine if EDTA treatment could effectively remove humic contaminants from bone collagen and thus serve as an alternative to the commonly implemented sodium hydroxide (NaOH) treatment, which may be associated with large collagen losses in poorly preserved samples. We compared the isotopic and elemental composition of ancient samples treated with EDTA alone, samples demineralized in hydrochloric acid (HCl) and rinsed in EDTA, samples treated with HCl alone, and samples demineralized in HCl and rinsed with NaOH. The samples used in the analyses were selected because they presented evidence of substantial humic contamination. We found that NaOH was the most effective agent for reducing humic contaminants as evidenced by the samples treated with this agent having higher δ13C values and lower C:N ratios relative to other treatments. The results from samples treated with EDTA suggest that this chemical cannot effectively remove humic contaminants given that these samples had significantly higher C:N ratios and lower δ13C and δ15N values relative to the HCl/NaOH treatment. Our results demonstrate that when performing stable isotope analysis of ancient bone collagen suspected to be contaminated with humic acids, NaOH is the most effective chemical agent to remove humic contaminants, while EDTA cannot perform this task.

Effect of alkali surface treatment and compatibilizer agent on tensile and morphological properties of date palm fibers‐based high density polyethylene biocomposites

AbstractThe objective of the present study is to develop an environment friendly alternative material based on available and local bio‐source from the wastes of Algerian date palm trees, date palm twigs fiber (DPF) was selected as an effective reinforcing material for high density polyethylene (HDPE) biocomposite. Two types of treatments have been used including sodium hydroxide (NaOH) treatment to obtain DPF1 followed by potassium permanganate (KMnO4) treatment to obtain DPF2 for aim to improve fiber‐matrix compatibility, HDPE biocomposite reinforced with different ratios of DPF1 and DPF2 varying from 10 to 30 wt% were elaborated, characterized, and compared to select the preferred treatment and percent of DPF which can be used with high properties. The results obtained indicates that the incorporating of 30 wt% of DPF2 in HDPE biocomposite led to an improve in the mechanical and morphological properties. In fact, the improvement in interfacial properties improve ultimate biocomposite performance, and thus qualified its use in different industrial application. The maleic anhydride grafted high‐density polyethylene (HDPE‐g‐MA) was incorporated as a coupling agent to the reinforced biocomposite of 30 wt% DPF2/HDPE with two different loading (7 and 10 wt%), Also, the treatments were seen to enhance the tensile strength and elastic modulus. Additionally, the biocomposites observation by scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed more intimate contact between the fibers and HDEP matrix after surface modification. The results suggested that the successful sample with best characteristics which can be advised is 30 wt% DPF2/HDPE/10 wt% HDPE‐g‐MA, that offer their use in many applications particularly in the automotive industry.

One-step sodium bisulfate hydrolysis for efficient production of xylooligosaccharides from poplar

Acid salts have been shown to catalyze xylan hydrolysis selectively and efficiently for xylooligosaccharides (XOS) production while using acid salts that are non-toxic and available as feed additives can avoid separation from resulting XOS-rich hydrolysates. There is no report on XOS production with sodium bisulfate (NaHSO4) hydrolysis, of significance is that NaHSO4 as feed additive does not need to be separated. In this work, NaHSO4 hydrolysis was firstly employed to produce XOS from poplar. XOS yield of 42.7% was reached under optimal conditions of 0.04 mol/L NaHSO4, 170 °C and 60 min. After hydrogen peroxide/acetic acid and sodium hydroxide treatments of NaHSO4-pretreated poplar, high yields of glucose (92.0%) and xylose (91.3%) were obtained at a low cellulase dose of 5 FPU/g dry mass. NaHSO4 hydrolysis was a novel strategy to prepare XOS efficiently with simple operation steps, and XOS-rich hydrolysates could be potentially used as feed additives without NaHSO4 separation.

Effect of Fibre Volume Fraction and Sodium Hydroxide Treatment on Mechanical Properties of Palm Fibre/Unsaturated Polyester Composite

Wood has some weaknesses, such as susceptibility to weathering, easily attacked by termites, and low water resistance. An alternative material such as Natural Fibre-Reinforced Polymer (NFRP) composite should overcome those weaknesses. This research aims to make a composite with palm fibre and unsaturated polyester resin. Palm fibres immerse for 2 hours in NaOH solution with varying concentrations of 3%, 5%, and 7%. The volume fraction of palm fibre are 0%, 5%, 10%, 15%, and 20%. Woven roving fibreglass was added to compare the tensile strength of composite with or without natural fibre. The density of composites increased with the increase of fibre volume fraction. The highest tensile strength was obtained for 15% of fibre volume fraction, namely 23.8483 MPa. In contrast, the highest compressive strength was obtained for 5% of fibre volume fraction, namely 94.76 MPa. NaOH removed the impurities and waxy substances from the fibre surface and created a rougher surface topography after alkalization. The highest tensile strength was obtained with 7% NaOH, namely 14.674 MPa. The highest water absorption value was obtained at 3% NaOH concentration and 15% of fibre volume fraction, namely 1.445%. The addition of woven roving as reinforcement to natural fibre composite can increase tensile strength by 210%, from 13.882 MPa to 43.123 MPa.

Valorization of Posidonia-Oceanica leaves for the building insulation sector

A new bio-composite material appropriate for building thermal insulation is proposed. The hydrophilic, thermal, and mechanical properties of composites made with Posidonia-Oceanica leaves, are experimentally investigated. The effect of two different sizes of fibers (natural and crushed leaves) as well as the effect of the chemical treatment (1% sodium hydroxide) are studied. For this purpose, different parallelepipedic specimens of dimensions 270 × 270 × 30 mm3 (thermal properties tests) and 160 × 40 × 40 mm3 (mechanical properties tests) were prepared by varying densities of leaves (0, 5, 10, 15, 20, and 30% by volume). In comparison to the fiber size effect, the results reveal that fiber loading has a significant impact on the mechanical and thermal characteristics of composites. Alkali treatment can improve the compressive and flexural strength of bio-composites. The novel bio-composites have low thermal conductivity (0.09 W.m−1K−1 when 30% of reduced size Posidonia-Oceanica leaves were loaded into the reference mortar) and acceptable mechanical performances. Results also show (1) The addition of treated fiber improves the ductility of the material. (2) The fracture toughness is 75% greater than reference mortar. (3) The use of crushed fibers decreases the composite’s mechanical strengths. (4) The flexural strength decreases with the fibers content and increase after 1% sodium hydroxide treatment. It can be concluded that the proposed bio-composite can be employed as thermal insulation material.

Characterization and Toxicity Evaluation of Broiler Skin Elastin for Potential Functional Biomaterial in Tissue Engineering.

Broiler skin, a by-product of poultry processing, has been proven to contain essential elastin, a high-value protein with many applications. The present study reported the extraction of water-soluble elastin from broiler skin by using sodium chloride (NaCl), sodium hydroxide (NaOH), and oxalic acid treatment before freeze-drying. Chemical characterization such as protein and fat content, Fourier-transform infrared (FTIR) spectroscopy, amino acid composition and thermal gravimetric analysis (TGA) were performed and compared with commercial elastin from bovine neck ligament. The resultant elastin’s toxicity was analyzed using an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium assay and primary skin irritation test. Results showed a high quality of the extracted-elastin with the presence of a high amount of proline (6.55 ± 0.40%) and glycine (9.65 ± 0.44%), low amount of hydroxyproline (0.80 ± 0.32%), methionine (2.04 ± 0.05%), and histidine (1.81 ± 0.05%) together with calculated 0.56 isoleucine/leucine ratio. FTIR analysis showed the presence of typical peaks of amide A, B, I, and II for protein with high denaturation temperature around 322.9 °C. The non-toxic effect of the extracted elastin was observed at a concentration lower than 0.5 mg/mL. Therefore, water-soluble elastin powder extracted from broiler skin can be an alternative source of elastin as a biomaterial for tissue engineering applications.

Improvement of the Degradation of Tensile and Impact Strength of Water-aged Sisal Fiber-reinforced Polyester Composites: A Comparative Study on the Effects of Hybridizations, Hybrid Layering Sequences, and Chemical Treatments

ABSTRACT This research aims to reduce the degradation of sisal fiber-reinforced polyester composites due to water absorption through chemical treatments and hybridizations. Sisal fibers were treated using sodium hydroxide (NaOH) and baking soda (NaHCO3). Unidirectional glass and carbon fibers were chosen as hybrid fibers. Thirteen laminates of pure sisal fibers, hybridized with glass or carbon fibers at different stacking sequences and volume fractions, were prepared using the hand layup technique. The laminates were examined for tensile and impact strength at dry and wet conditions. The effects of baking soda and sodium hydroxide treatments, glass and carbon fibers hybridization, and the sequence and volume of the hybrid fibers on the tensile strength, impact strength, water absorption, and degradation of the laminates were studied and compared. Chemical treatments and hybridizations have enhanced the tensile and impact strength of the composites. Significant reduction in the water uptake rate and degradation of the laminates were observed. Almost 166% and 87%, respectively, improvements were obtained in the tensile and impact strength of the dry samples. Moreover, more than 74% reduction in water uptake, and 84.7% and 91.7%, respectively, improvements in the degradation of the tensile and impact strengths were discovered.

Bioprocess development for production of xylooligosaccharides prebiotics from sugarcane bagasse with high bioactivity potential

The xylooligosaccharides (XOS, prebiotics) production from xylan extracted from sugarcane bagasse (SB) biomass was accomplished using an in-house produced xylosidase-free endoxylanase from an isolate Aspergillus flavus MG-7. Delignification of SB by sodium hypochlorite, and xylan extraction by coupled sodium hydroxide and thermal treatment were optimized for various process variables based on Design of Experiments (DoE) to achieve enhanced xylan yield (96.11%, w/w). The extracted xylan was analysed by Fouriertransform infrared spectroscopy and thermogravimetric analysis to evaluate its structural morphology, purity and thermal stability. Xylan hydrolysate obtained by endoxylanase was quantified for xylobiose (69.57%, w/w), xylotriose (13.17%) and xylotetrose (8.377%), and XOS were examined by 1H NMR. Growth-promoting potential of XOS was established for a probiotic Lactobacillus plantarum M-13 isolated from kalarei. XOS exhibited excellent bioactivity potential in terms of high positive prebiotic activity score, significant antioxidant activity and antibacterial activity. Efficient XOS production promises value-addition for biorefining of SB biomass.

Fatigue damage propagation and creep behavior on sisal/epoxy composites

The lack of knowledge about the behavior under creep and fatigue limits the use of polymeric composites reinforced with natural fibers. Thus, this work assessed the behavior of epoxy composites reinforced with sisal fibers under tensile, fatigue, and creep tests. Also, thermogravimetry and scanning electron microscopy assessed the sodium hydroxide (NaOH) treatment efficiency in sisal fibers. Further, differential scanning calorimetry determined the degree of cure of the composites, and stereomicroscopy allowed the evaluation of the surface’s fracture. As a result, the tensile strength of the composite was 1.4 times the value of neat epoxy resin after 100,000 cycles in the fatigue test. Moreover, when loaded with 20% of the maximum tensile strength, it is estimated that the composite resists 200,000 h without rupturing by creep. To conclude, the efficient adhesion between sisal fibers and epoxy obtained by NaOH treatment allowed good mechanical behavior to the epoxy composite.

Effects of Chemical Treatment on the Physical Properties of Typha

Plant-based concretes are produced from plant aggregates and a binder. Plant fibers are mainly composed of saccharides (sugars) and these sugars can decrease the concentration of Ca2+ ions in the cement pore solution and delay the formation of hydration products. To improve the interfacial bond between fibers and matrix a chemical treatment is widely used. This study investigates the effect of sodium hydroxide treatment on physical and hygroscopic properties of Typha aggregates. In particular, a 5% sodium hydroxide solution is used to treat these aggregates and their bulk and absolute densities, porosity, water content and water absorption are evaluated accordingly. Results indicate that bulk and absolute densities increase after treatment from 56.44 kg/m3 to 122.57 kg/m3 and 541.93 kg/m3 to 555.17 kg/m3, respectively. NaOH treatment reduces porosity of Typha from 89.58 % to 77.92% and decreases water content from 1.4 % to 1%. The treatment with sodium hydroxide reduces substantially the water absorption of the aggregates.

Towards the development of sustainable concrete incorporating waste tyre rubbers: A long-term study of physical, mechanical & durability properties and environmental impact

The dramatic increase in the demand for vehicle tyres and consequently the rapid rise in associated waste rubber has been a concern for several decades. Rubber disposal has adverse effects on the environment, human health and a detrimental effect on sustainable development across the world. This paper investigates the effectiveness of a sodium hydroxide treatment method for waste rubber in addition to the utilisation of silica fume to improve the interfacial transition zone between the rubber and cement matrix. This has been shown to have important implication for the long-term development of physical and mechanical properties of concrete aged for 2 years. This study emphasises that while satisfactory improvements are attained through the rubber treatment alone, the actual performance of rubberized concrete containing silica fume could only be investigated over the long term owing to the slow pozzolanic reaction and its dependency on the formation of calcium hydroxide. The pre-treatment of rubber and more specifically the utilisation of silica fume improved the durability of concrete over rubber replacement levels from ∼20% to 40%. Long-term thermal conductivity and sound permeability of concrete containing tyre rubber were shown to have important consequences in energy conservation and social sustainability in construction practice. Results reported on the cost efficiency and consequently the CO2 emissions of concrete containing rubber do not only enhance awareness of the development of sustainable construction materials but also lead a cleaner alternative waste management route for tyre rubber.

Review of rice husk silica as a heterogeneous catalyst support

The yield of amorphous silica has less residue of mineral content in rice husk (RH) and a high specific surface area through the simple alkaline extraction process at first, then acid precipitation of RH. At this time, the leaching process using alkali and calcination of RH is the best method to acquire amorphous silica with a high surface area. The different temperatures were used for the calcination of RH and continue with sodium hydroxide (NaOH) treatment by using different concentration. The sample titrated using hydrochloric acid (HCl) to extract silica. Pretreatment with acid leaching for the RH was also conducted before the calcination of the RH. Results acquired were analysed and compared.

Alkali Concentration and Diluent Effects on Properties of Grape Cane Fiber-Reinforced Polymer Composites.

The main objective of this study was to investigate the properties of polymer composites reinforced with grape cane fibers. The fibers were subjected to a sodium hydroxide (NaOH) treatment at two treatment concentrations to extract the fibers as well as fiber surface treatment. Panels were fabricated by hand lay-up and compression molding according to different fiber types, namely outer bark (OB) and whole (W) fibers. The whole fiber was a mixture of OB and inner bark (IB) fibers. Grape cane fibers were used as the reinforcement material for unsaturated polyester (UPE) resin panels. Acrylated epoxidized soybean oil (AESO) was used as a reactive diluent material with the UPE resin, and the results were compared with panels prepared with commercial styrene–UPE. There were inconsistent alkali treatment concentration effects on the mechanical properties and water absorption. However, panels fabricated with the whole bark fibers that have been treated with 1 wt % NaOH and had AESO–UPE resin resulted in the best tensile and flexural strength.

Sodium Hydroxide Treatment for Cellulose Fiber Accessibility from Corncobs under Microwave Assistive

Corncob is abundantly available lignocellulosic biomass resources obtained from crops harvesting and found to be solid waste accumulation on a field. Less corncob is used as a solid fuel for cooking, and a more significant portion is vanished on the field by burning. Promisingly, corncob contains considerable cellulose as one value-added component potentially utilized as biomaterial or biofuel feedstock. However, the presence of lignin in natural lignocellulosic biomass results in recalcitrant structure and hinders cellulose accessibility. This study aimed to investigate microwave-assisted alkaline treatment to retain cellulose in the solid product while removing other impurities in corncob, especially hemicellulose and lignin. Sodium hydroxide was selected as a chemical with some variations in concentration. The chemical treatment was carried out under 400 W microwave power with various residence times and a 1:10 solid to liquor ratio. The cellulose content upgraded from 26.97% to 71.26% while reducing hemicellulose and lignin from 38.49% to 18.15% and 19.28% to 6.4%, respectively, on chemical treatment using 8% sodium hydroxide concentration for 20 minutes residence time. Scanning electron microscope (SEM) and Fourier transform infrared (FTIR) analysis also confirmed the results. The treated corncob also increased its crystallinity from 30.11% to 52.91%.

Influence of nixtamalization cooking ingredients on the minerals composition of nixtamalized maize and sorghum

Nixtamalization is one of the identified processing techniques to reduce mycotoxins contamination in food. In this study, the effect of five nixtamalization cooking ingredients (wood ashes, calcium hydroxide, sodium hydroxide, potassium hydroxide and calcium chloride) on the minerals composition of maize and sorghum was investigated using inductively coupled plasma technology. Cooking of maize and sorghum with sodium hydroxide, calcium hydroxide and potassium hydroxide respectively gave rise to significantly (p < 0.05) highest concentration of Na, Ca, and K with all the cooking ingredients having a reducing effect on P. Maize samples cooked with potassium hydroxide had the highest level of most of the considered essential trace elements while for sorghum, wood ashes treatment brought about the richest level of Mn, Zn and V. Although some of the nixtamalized samples had unsafe Na/K ratio (sodium hydroxide treatment samples) and Al levels (wood ashes treatment samples), they all had their Cd and Pb contents below the FAO/WHO Codex Alimentarius recommended maximum levels. Generally, the study revealed that potassium hydroxide is an ideal cooking ingredient to address the low concentration of Cu, Zn and Fe common in tortillas while removal of pericarp during nixtamalization may not always bring about loss of dietary minerals.