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1.
Environ Geochem Health ; 46(6): 182, 2024 May 02.
Article in English | MEDLINE | ID: mdl-38695980

ABSTRACT

Due to the development of industries such as mining, smelting, industrial electroplating, tanning, and mechanical manufacturing, heavy metals were discharged into water bodies seriously affecting water quality. Bamboo charcoal, as an environmentally friendly new adsorbent material, in this paper, the virgin bamboo charcoal (denoted as WBC) was modified with different concentrations of KMnO4 and NaOH to obtain KMnO4-modified bamboo charcoal (KBC) and NaOH-modified bamboo charcoal (NBC) which was used to disposed of water bodies containing Cu2+ and Zn2+. The main conclusions were as following: The adsorption of Cu2+ by WBC, KBC and NBC was significantly affected by pH value, and the optimum pH was 5.0. Differently, the acidity and alkalinity of the solution doesn't effect the adsorption of Zn2+ seriousely. Meanwhile, surface diffusion and pore diffusion jointly determine the adsorption rate of Cu2+ and Zn2+. The test result of EDS showed that Mn-O groups formed on the surface of K6 (WBC treated by 0.06 mol/L KMnO4) can promote the adsorption of Cu2+ and Zn2+ at a great degree. The O content on N6(WBC treated by 6 mol/L NaOH) surface increased by 30.95% compared with WBC. It is speculated that the increase of carbonyl group on the surface of NBC is one of the reasons for the improvement of Cu2+ and Zn2+ adsorption capacity. Finally, the residual concentrations of Cu2+ and Zn2+ in wastewater are much lower than 0.5 mg/L and 1.0 mg/L, respectively. Thus it can be seen, KBC and NBC could be a promising adsorbent for heavy metals.


Subject(s)
Charcoal , Copper , Water Pollutants, Chemical , Zinc , Adsorption , Zinc/chemistry , Copper/chemistry , Charcoal/chemistry , Water Pollutants, Chemical/chemistry , Hydrogen-Ion Concentration , Potassium Permanganate/chemistry , Water Purification/methods , Sasa/chemistry , Sodium Hydroxide/chemistry
2.
Sci Rep ; 14(1): 12088, 2024 05 27.
Article in English | MEDLINE | ID: mdl-38802402

ABSTRACT

Nowadays, scientists are currently attempting to lessen the harmful effects of chemicals on the environment. Stability testing identifies how a drug's quality changes over time. The current work suggests a first and sustainable differential pulse voltammetry technique for quantifying difluprednate (DIF) as an anti-inflammatory agent in the presence of its alkaline degradation product (DEG). The optimum conditions for the developed method were investigated with a glassy carbon electrode and a scan rate of 100 mV s-1. The linearity range was 2.0 × 10-7-1.0 × 10-6 M for DIF. DIF was found to undergo alkaline degradation, when refluxed for 8 h using 2.0 M NaOH, and DEG was successfully characterized utilizing IR and MS/MS. The intended approach demonstrated the selectivity for DIF identification in pure, pharmaceutical, and degradation forms. The student's t-test and F value were used to compare the suggested and reported approaches statistically. The results were validated according to ICH requirements. The greenness of the studied approach was evaluated using the Green Analytical Procedure Index and the Analytical Greenness metric. Additionally, the whiteness features of the proposed approach were examined with the recently released red, green, and blue 12 model, and the recommended strategy performed better than the reported approaches in greenness and whiteness.


Subject(s)
Electrochemical Techniques , Electrochemical Techniques/methods , Electrodes , Sodium Hydroxide/chemistry , Tandem Mass Spectrometry/methods , Hydrogen-Ion Concentration , Green Chemistry Technology/methods
3.
Eur Biophys J ; 53(4): 225-238, 2024 May.
Article in English | MEDLINE | ID: mdl-38613566

ABSTRACT

Calibration of titration calorimeters is an ongoing problem, particularly with calorimeters with reaction vessel volumes < 10 mL in which an electrical calibration heater is positioned outside the calorimetric vessel. Consequently, a chemical reaction with a known enthalpy change must be used to accurately calibrate these calorimeters. This work proposes the use of standard solutions of potassium acid phthalate (KHP) titrated into solutions of excess sodium hydroxide (NaOH) or excess tris(hydroxymethyl)aminomethane (TRIS) as standard reactions to determine the collective accuracy of the relevant variables in a determination of the molar enthalpy change for a reaction. KHP is readily available in high purity, weighable for easy preparation of solutions with accurately known concentrations, stable in solution, not compromised by side reactions with common contaminants such as atmospheric CO2, and non-corrosive to materials used in calorimeter construction. Molar enthalpy changes for these reactions were calculated from 0 to 60 °C from reliable literature data for the pKa of KHP, the molar enthalpy change for protonation of TRIS, and the molar enthalpy change for ionization of water. The feasibility of using these reactions as enthalpic standards was tested in several calorimeters; a 50 mL CSC 4300, a 185 µL NanoITC, a 1.4 mL VP-ITC, and a TAM III with 1 mL reaction vessels. The results from the 50 mL CSC 4300, which was accurately calibrated with an electric heater, verified the accuracy of the calculated standard values for the molar enthalpy changes of the proposed reactions.


Subject(s)
Calorimetry , Sodium Hydroxide , Tromethamine , Sodium Hydroxide/chemistry , Calibration , Tromethamine/chemistry , Temperature , Reference Standards , Thermodynamics
4.
J Mol Graph Model ; 130: 108779, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38657395

ABSTRACT

Scorodites are commonly used for arsenic immobilization, and it is also the main component of arsenic bearing tailings. Alkali-activated geopolymers are commonly used to landfill arsenic-bearing minerals. However, there no previous studies have explored the interaction between geopolymer molecules and the surface of scorodite. In this paper, Si(OH)4 as a monomer molecule of geopolymer, the mechanism of adsorption and 'ion exchange' between Si(OH)4 molecule and the surface of scorodite during alkali-activation is studied. Results show that the Fe-terminated scorodite (010) surface has high stability. Si(OH)4 are more easily adsorbed on the hollow site of an Fe-terminated scorodite (010) surface, which is described as chemisorption. Compared with Si(OH)4, NaOH is easier to adsorb on an Fe-terminated scorodite (010) surface. The co-adsorption of NaOH and Si(OH)4 on the Fe-terminated scorodite (010) surface was studied, and also belongs to chemical adsorption. When the hydroxyl binds to the As atom, the adsorbed Si(OH)4 is more likely to undergo an 'ion exchange' reaction with the surface, and the reaction is barrierless. The intermediate As(OH)4 produced by the 'ion exchange' reaction can be deprotonated to form an arsenate molecule, which can occur spontaneously. This work reveals that the interaction mechanism of geopolymer molecules on surface of scorodite.


Subject(s)
Surface Properties , Adsorption , Ion Exchange , Arsenic/chemistry , Sodium Hydroxide/chemistry , Iron/chemistry
5.
Environ Sci Pollut Res Int ; 31(22): 32800-32812, 2024 May.
Article in English | MEDLINE | ID: mdl-38664320

ABSTRACT

The highly stable biomass structure formed by cellulose, hemicellulose, and lignin results in incomplete conversion and carbonization under hydrothermal conditions. In this study, pretreated corn straw hydrochar (PCS-HC) was prepared using a low-temperature alkali/urea combination pretreatment method. The Mass loss rate of cellulose, hemicellulose, and lignin from pretreated biomass, as well as the effects of the pretreatment method on the physicochemical properties of PCS-HC and the adsorption performance of PCS-HC for alkaline dyes (rhodamine B and methylene blue), were investigated. The results showed that the low-temperature NaOH/urea pretreatment effectively disrupted the stable structure formed by cellulose, hemicellulose, and lignin. NaOH played a dominant role in solubilizing cellulose and the combination of low temperature and urea enhanced the ability of NaOH to remove cellulose, hemicellulose, and lignin. Compared to the untreated hydrochar, PCS-HC exhibited a rougher surface, a more abundant pore structure, and a larger specific surface area. The unpretreated hydrochar exhibited an adsorption capacity of 64.8% for rhodamine B and 66.32% for methylene blue. However, the removal of rhodamine B and methylene blue by PCS-BC increased to 89.12% and 90.71%, respectively, under the optimal pretreatment conditions. The PCS-HC exhibited a favorable adsorption capacity within the pH range of 6-9. However, the presence of co-existing anions such as Cl-, SO42-, CO32-, and NO3- hindered the adsorption capacity of PCS-HC. Among these anions, CO32- exhibited the highest level of inhibition. Chemisorption, including complexation, electrostatic attraction, and hydrogen bonding, were the primary mechanism for dye adsorption by PCS-HC. This study provides an efficient method for utilizing agricultural waste and treating dye wastewater.


Subject(s)
Sodium Hydroxide , Urea , Wastewater , Water Pollutants, Chemical , Adsorption , Sodium Hydroxide/chemistry , Urea/chemistry , Wastewater/chemistry , Water Pollutants, Chemical/chemistry , Coloring Agents/chemistry , Lignin/chemistry , Cellulose/chemistry , Rhodamines/chemistry , Temperature
6.
Environ Sci Pollut Res Int ; 31(19): 28379-28391, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38536573

ABSTRACT

To enhance the adsorption performance of municipal sludge biochar on Cd(II), modified sludge biochar was prepared by sodium hydroxide/magnesium chloride (NaOH/MgCl2) graded activation, and the Cd(II) adsorption performance on sludge biochar (BC), NaOH-activated sludge biochar (NBC) and NaOH/MgCl2 activated sludge biochar (NBC-Mg) was investigated. The results showed that NaOH/MgCl2 graded activation upgraded the surface structure and enhanced the graphitization of sludge biochar. The adsorption experiments indicated that the adsorption kinetic and adsorption isotherm for Cd(II) were in accordance with the pseudo second-order kinetic and Langmuir model. The adsorption capacity of NBC-Mg (143.49 mg/g) for Cd(II) was higher than that of BC (50.40 mg/g) and NBC (85.20 mg/g). The mechanism of Cd(II) adsorption included ion exchange, complexation, cation-π interaction, and mineral precipitation. After five regeneration, the removal efficiency of Cd(II) by NBC-Mg remained above 90%. This work indicated that sludge biochar prepared by multistage activation could be an effective material for Cd-containing wastewater treatment.


Subject(s)
Cadmium , Charcoal , Magnesium Chloride , Sewage , Sodium Hydroxide , Adsorption , Cadmium/chemistry , Charcoal/chemistry , Sewage/chemistry , Magnesium Chloride/chemistry , Sodium Hydroxide/chemistry , Kinetics , Water Pollutants, Chemical/chemistry
7.
Int J Biol Macromol ; 266(Pt 1): 131193, 2024 May.
Article in English | MEDLINE | ID: mdl-38552703

ABSTRACT

Beyond the conventional consideration of pretreatment severity (PS) responsible for biomass disruption, the influence of reagent properties on biomass (LCB) disruption is often overlooked. To investigate the LCB disruption as a function of reagent properties, reagents with distinct cations (NaOH and KOH) and significantly higher delignification potential were chosen. NaOH solution (3 % w/v) with a measured pH of 13.05 ± 0.01 is considered the reference, against which a KOH solution (pH = 13.05 ± 0.01) was prepared for LCB pretreatment under the same PS. Despite comparable lignin content, varying glucose yield of NaOH (68.76 %) and KOH (46.88 %) pretreated residues indicated the presence of heterogeneously disrupted substrate. Holocellulose extracted from raw poplar (ASC, control) and alkaline pretreated residues (C-NaOH and C-KOH) were analyzed using HPLC, XRD, SEM, TGA/DTG, XPS, and 13CP MAS NMR to investigate the pretreatment-induced structural modification. Results revealed that, despite the same pretreatment severity, better disruption in C-NaOH (higher accessible fibril surface and less-ordered region) leading to higher digestibility than C-KOH, likely due to the smaller ionic radius of Na+, facilitates better penetration into dense LCB matrix. This study elucidates the importance of considering the reagent properties during LCB pretreatment, eventually enhancing consciousness while selecting reagents for efficient LCB utilization.


Subject(s)
Biomass , Hydroxides , Lignin , Sodium Hydroxide , Lignin/chemistry , Sodium Hydroxide/chemistry , Hydroxides/chemistry , Hydrolysis , Populus/chemistry , Potassium Compounds/chemistry , Indicators and Reagents/chemistry , Hydrogen-Ion Concentration
8.
Carbohydr Res ; 536: 109054, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38350405

ABSTRACT

The dissolution of microcrystalline cellulose (MCC) in a urea-NaOH system is beneficial for its mechanical processing. The apparent MCC solubility was greatly improved to 14 wt% under a slow-cooling condition with a cooling rate of -0.3 °C/min. The cooling curve or thermal history played a crucial role in the dissolution process. An exotherm (-54.7 ± 3 J/g MCC) was detected by DSC only under the slow-cooling condition, and the cryogenic dissolution of MCC was attributed to the exothermic interaction between MCC and solvent. More importantly, the low cooling rate promoted the dissolution of MCC by providing enough time for the diffusion of OH- and urea into MCC granules at higher temperatures. The Raman spectral data showed that the intramolecularly and intermolecularly hydrogen bonds in cellulose were cleaved by NaOH and urea, respectively. XPS and solid-state 13C NMR results showed that hydrogen bonds were generated after dissolution, and a dual-hydrogen-bond binding mode between urea and cellulose was confirmed by DFT calculations. Both the decrease of enthalpy and increase of entropy dominated the spontaneity of MCC dissolution, and that is the reason for the indispensability of cryogenic environment. The high apparent solubility of MCC in the slow-cooling process and the dissolution mechanism are beneficial for the studies on cellulose modification and mechanical processing.


Subject(s)
Alkalies , Urea , Urea/chemistry , Sodium Hydroxide/chemistry , Solubility , Cellulose/chemistry
9.
Sci Rep ; 14(1): 2986, 2024 02 05.
Article in English | MEDLINE | ID: mdl-38316914

ABSTRACT

Cattle dung treatments in Taiwan have developed a process called Black soldier fly larvae (BSFL) treatment, which can digest cow dung and generate the frass (larvae drops), the residue fiber in cow dung. This study aims to assess frass for its potential in pulp and papermaking, considering its chemical compositions, appearance, and fiber morphology, and also evaluate its suitability for pulping by soda method to create added value. The frass exhibits favorable material properties for pulping and papermaking, including a high holocellulose (67.37%) and α-cellulose (48.00%) content, along with a lower ash content (4.61%); the microstructure and surface mesoporous pores benefit for pulping; and the nonwood-fiber-like fiber morphology. The pulping experiment shows that 7% NaOH and 75 min of pulping conditions result in proper disintegration of fiber, and the highest accepts ratio (34.06%). The NaOH causes fiber disintegration during pulping, resulting in a higher strength property of the handsheet. The frass pulp blended with TOCC can achieve the ring crush index standards required for cardboard products. In summary, the frass from BSFL treatment of cattle dung can be utilized in pulp and papermaking to enhance circular utilization value.


Subject(s)
Diptera , Female , Cattle , Animals , Larva , Sodium Hydroxide/chemistry , Cellulose/chemistry , Feces
10.
Environ Sci Pollut Res Int ; 31(9): 13638-13655, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38253834

ABSTRACT

Anaerobic digestion is one of the best options for producing valuable end products (biogas and biofertilizer). The aim of this study was to investigate the influences of thermoalkaline pretreatment of wheat straw on biogas production and digestate characteristics from codigestion with waste-activated sludge. Different alkaline conditions (NaOH, KOH and Na2CO3) and pretreatment durations (1, 3 and 5 h) were used for straw pretreatment. Batch anaerobic codigestion of sludge and pretreated straw was conducted under different pretreatment conditions. A feedforward neural network (FFNN) model, logistic model and statistical analysis were applied to the experimental data to predict biogas and investigate the significance and relationships among the variables. NaOH pretreatment for 5 h showed the best treatment conditions: biogas yield was 6.59 times higher than that without treatment. Moreover, the proportions of total solids, total volatile solids, chemical oxygen demand and microbial count removed reached 63.52%, 74.60%, 78.15% and 82.22%, respectively. The methane content was 67.50%, indicating that the biogas had a high quality. The thermoalkaline pretreatment significantly affected biogas production and digestate characteristics, allowing it to be used as a biofertilizer. Experimental data were successfully modelled for predicting biogas production using the applied models. The R2 values reached 0.985 and 0.999 for the logistic and FFNN models, respectively.


Subject(s)
Biofuels , Sewage , Anaerobiosis , Sodium Hydroxide/chemistry , Triticum , Methane , Bioreactors
11.
Sci Rep ; 13(1): 21230, 2023 12 01.
Article in English | MEDLINE | ID: mdl-38040821

ABSTRACT

Oyster Farming is one of important fisheries and aquaculture industries in Taiwan. Each year, approximately 4000-5000 tons of discarded bamboo scaffolding (BS) used in oyster farming, are generated, so the treatment and utilization of BS should be taken seriously. This study evaluates the suitability of BS for pulp and papermaking by assessing the chemical compositions, microstructural, and fiber morphology. The pulping properties is investigated by soda pulping. The chemical composition of BS shows the potential for application in pulping. The BS microstructure shows that can enhance pulping reactions, while the fiber morphology indicates the possibility of producing high-strength paper. Through the pulping experiment, it demonstrated that BS is suitable for pulping with lower NaOH dosage and longer digestion time. The condition at 170 °C with 14% NaOH dosage for 90 min digestion has the highest yield. After refining the highest pulping yield BS pulp, it can improve the handsheet strength and bulk of the OCC-BS mixed pulp, which can achieve the strength property required for industrial paper. In summary, BS exhibits the potential for pulping application and produces a better paper strength than OCC pulp, exhibiting the feasibility of enhancing the circular utilization value of BS in Taiwan.


Subject(s)
Cellulose , Paper , Sodium Hydroxide/chemistry , Cellulose/chemistry , Industry , Agriculture
12.
Carbohydr Res ; 534: 108982, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37976957

ABSTRACT

A series of sulfopropyl chitins (SCs) with the degree of substitution (DS) ranging from 0.11 to 0.40 and high degree of acetylation (DA ≥ 0.82) were homogeneously synthesized by reacting chitin with sodium 3-chloro-2-hydroxypropanesulfonate (SCHPS) in NaOH/urea aqueous solutions under mild conditions. The structure and properties of SCs were characterized with 1H NMR, CP/MAS 13C NMR, FT-IR, XPS, XRD, elemental analysis, GPC, AFM, ζ-potential and rheological measurements. The mild reaction conditions resulted in less N-deacetylation and uniform structures with substitution occurring predominantly at the hydroxyl groups at C6 of the chitin backbone. The DS value for SC soluble in dilute alkali solution is as low as 0.16. SC exhibited good solubility in distilled water when its DS value reached 0.28. Water-soluble SCs self-assembled in water into micelles by the attractive hydrophobic and hydrogen-bonding interactions between polymer chains. The water-insoluble SC-2 with lower DS could thermally form smart hydrogels at body temperature (37 °C) in physiological condition. Moreover, the SCs exhibited good biocompatibility, making them suitable for biomedical applications.


Subject(s)
Chitin , Urea , Urea/chemistry , Chitin/chemistry , Sodium Hydroxide/chemistry , Spectroscopy, Fourier Transform Infrared , Water/chemistry , Solutions
13.
Carbohydr Res ; 534: 108971, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37862856

ABSTRACT

This study presents a method for solvent-free mechanochemical synthesis of chitosan from chitin, sourced from the shells of mud crabs (Scylla serrata). The procedure involves a sequence of demineralization and deproteinization to extract chitin from the crab shells, followed by mechanochemical deacetylation. The chitin was deacetylated by grinding it as a solid blend with sodium hydroxide (NaOH) using a stainless steel mortar and pestle. After grinding, chitosan is isolated from the blend by repetitive washing and centrifugation. The chitosan product is then characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction analysis. These characterization techniques confirm the successful deacetylation of chitin to form chitosan. A high degree of deacetylation (DD) is achieved when the weight ratio of NaOH to chitin is 1:1 or higher, implying that the DD value can be enhanced by increasing this weight ratio. The mechanochemical reaction mechanism involves the hydroxyl groups on the NaOH particles reacting with the acetamide groups of the chitin strands, yielding solid chitosan and sodium acetate. This mechanochemical deacetylation approach is more practical than the conventional heterogeneous deacetylation in strong basic solutions, since it could suppress depolymerization of the resulting chitosan and requires significantly less base. This makes it a promising method for large-scale industrial applications.


Subject(s)
Brachyura , Chitosan , Animals , Chitosan/chemistry , Chitin/chemistry , Sodium Hydroxide/chemistry , Spectroscopy, Fourier Transform Infrared
14.
J Chromatogr A ; 1698: 463982, 2023 Jun 07.
Article in English | MEDLINE | ID: mdl-37087858

ABSTRACT

In the biopharmaceutical industry, chromatography resins have a finite number of uses before they start to age and degrade, typically due to losses of ligand integrity and/or density. The "health" of a column is predicted and validated by running multiple cycles on representative scale-down models and can be followed by real-time on-going validation during commercial production. Principal Component Analysis (PCA), Partial Least Square (PLS), Similarity Scores and Single One Point-MultiParameter Technique (SOP-MPT) along with machine learning principles were applied to explore the hypothesis that there is predictive capability of latent variables in chromatography absorbance profiles for process performance (step yield) and product quality (aggregates, fragments, host cell proteins (HCP) and DNA, and Protein A ligand). The first stage of this study is described in this paper: a MabSelect SuRe™ chromatography column was cycled with a method to establish the "normal" baseline for process performance and product quality, followed by runs using a harsher NaOH Cleaning in Place (CIP) procedure (with a higher NaOH concentration than that recommended by the vendor) to accelerate resin degradation. The different mathematical analytical tools correlated with resin degradation of the column (reflected in decreasing step yield and binding capacity with increasing running cycle), specifically when using the Wash, Elution and Strip phases of the chromatography method. Monomer, HCP and DNA content were not significantly impacted and therefore a correlation with product quality was inconsequential. Importantly, this work shows proof-of-concept that while more traditional methods of measuring resin integrity such as the height equivalent to a theoretical place (HETP) and Asymmetry (As) measurements could not detect changes in the integrity of the resin, PCA, PLS, Similarity Scores and SOP-MPT (to a lesser extent) applied to the absorbance data were capable of anticipating issues in the chromatography bed by identifying atypical outcomes.


Subject(s)
Chromatography, Affinity , Chromatography, Affinity/instrumentation , Chromatography, Affinity/methods , Proteins , Sodium Hydroxide/chemistry , DNA/chemistry , Models, Chemical
15.
Bioresour Technol ; 380: 129070, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37088427

ABSTRACT

Pretreatment is important to overcome the structural recalcitrance of reed (a viable energy grass) to produce fermentable sugar. Herein, the study reported the pretreatment of reed using different alkali chemicals (sodium hydroxide/anthraquinone, sodium hydroxide/sodium sulfite, sodium hydroxide/sodium sulfide, ammonia/hydrogen peroxide, triethanolamine, and ammonia/sodium sulfite). The comparative study showed that the pretreatment using ammonia and sodium sulfite (NS) performed the best among them. The NS pretreatment of reed was further optimized using the Response Surface Methodology (RSM). The results showed that about 90.36% lignin was removed when reed was pretreated with 10 wt% of ammonia and 10% of sodium sulfite at 172 °C for 20 min. The excellent lignin removal performance was attributable to the synergistic effects between ammonia and sodium sulfite. The NS pretreated reed achieved 85.6% of enzymatic hydrolysis efficiency and 64.83% of total sugar yield.


Subject(s)
Cellulase , Lignin , Lignin/chemistry , Ammonia , Sodium Hydroxide/chemistry , Cellulase/chemistry , Sugars , Hydrolysis
16.
Dent Mater J ; 42(3): 390-395, 2023 May 30.
Article in English | MEDLINE | ID: mdl-36858626

ABSTRACT

Ti-50Zr alloy is 2.5 times as strong as pure Ti and has a lower Young's modulus, making it a useful material for repairing bone and teeth. However, Ti-50Zr alloy has a limited ability to bond with bone in vivo. Under biological conditions, apatite formation at the surface of a Ti or alloy implant is necessary for its bonding with bone. Various approaches to surface modification have been proposed to impart bone-bonding ability to Ti-50Zr alloy; however, there remains a need for further improvements to the alloy's apatite-forming ability. Hence, in this study, we compared apatite formation at the surface of alloy substrates in simulated body fluid, after various surface treatments. Treatment with 5 M NaOH followed by 1 M CaCl2 was the most effective procedure, whereas a sample subjected to a hot water post-treatment formed less apatite. Notably, no apatite formed on samples treated with 10 M NaOH.


Subject(s)
Alloys , Apatites , Surface Properties , Apatites/chemistry , Alloys/chemistry , Titanium/chemistry , Sodium Hydroxide/chemistry , Microscopy, Electron, Scanning
17.
Int J Biol Macromol ; 237: 124121, 2023 May 15.
Article in English | MEDLINE | ID: mdl-36966858

ABSTRACT

A scheme combining alkali­oxygen cooking and ultrasonic etching cleaning was developed for the short range preparation of CNF from bagasse pith, which has a soft tissue structure and is rich in parenchyma cells. This scheme expands the utilization path of sugar waste sucrose pulp. The effect of NaOH, O2, macromolecular carbohydrates, and lignin on subsequent ultrasonic etching was analyzed, and it was found that the degree of alkali­oxygen cooking was positively correlated with the difficulty of subsequent ultrasonic etching. The mechanism of ultrasonic nano-crystallization was found to be the bidirectional etching mode from the edge and surface cracks of the cell fragments by ultrasonic microjet in the microtopography of CNF. The optimum preparation scheme was obtained under the condition of 28 % NaOH content and 0.5 MPa O2, which solves the problem of low-value utilization of bagasse pith and environmental pollution, providing a new possibility for the source of CNF.


Subject(s)
Alkalies , Oxygen , Oxygen/chemistry , Alkalies/chemistry , Sodium Hydroxide/chemistry , Ultrasonics , Cellulose/chemistry , Carbohydrates , Cooking
18.
Int J Biol Macromol ; 224: 483-495, 2023 Jan 01.
Article in English | MEDLINE | ID: mdl-36273545

ABSTRACT

Hydrogels are an attractive platform for drug delivery to the skin. Current cellulose hydrogel developments commonly focus on readily available bleached woody cellulose. Considering the detrimental environmental impacts of bleaching reagents, unbleached non-woody biomass was proposed as an alternative. Herein, this study aims to develop hydrogel from native cellulose extracted from oil palm empty fruit bunches for dermal drug delivery with an emphasis on evaluating the effect of alkali solvent compositions on hydrogel formation. Unbleached dissolving pulps were solubilized in alkali solvents containing sodium hydroxide (NaOH) (6-8%w/v) and urea (4-6%w/v) before crosslinking. Hydrogels were loaded with ibuprofen for skin permeation studies. Light brownish hydrogels formed are aesthetically acceptable and biodegradable with low cytotoxicity. NaOH content has a dominant role over urea where thinner and deformable crosslinked network walls in a porous hydrogel structure are associated with high NaOH content. Synergistic effects (cellulose solubility: 94 %; swelling ratio: ~2800 %) were observed at 7%w/v NaOH and 4%w/v urea with low toxicity. Most hydrogels showed >80 % of ibuprofen permeated into the skin and this increased with the swelling ratio of hydrogels. Unbleached cellulose pulps have excellent potential for hydrogel fabrication with outstanding physicomechanical properties for dermal drug delivery.


Subject(s)
Anti-Infective Agents , Hydrogels , Hydrogels/chemistry , Cellulose/chemistry , Sodium Hydroxide/chemistry , Biomass , Ibuprofen , Solvents , Urea/chemistry
19.
Environ Sci Pollut Res Int ; 30(2): 5267-5279, 2023 Jan.
Article in English | MEDLINE | ID: mdl-35982388

ABSTRACT

Geopolymer bricks from lead glass sludge (LGS) and alumina flakes filling (AFF) waste were synthesized in the present work. AFF waste was chemically treated to prepare sodium aluminate (NaAlO2) powder. Silicate source (untreated LGS and thermally treated one at 600 °C (LGS600)) and sodium oxide (Na2O) concentration (as NaAlO2) were the compositional parameters, which affected the physical and mechanical properties (compressive strength, water absorption, and bulk density) of the prepared bricks. High organic matter content inside LGS caused a retardation effect on the geopolymerization process, resulting in the formation of hardened bricks with modest 90-day compressive strengths (2.13 to 4.4 MPa). Using LGS600 enhanced the mechanical properties of the fabricated bricks, achieving a maximum 90-day compressive strength of 22.35 MPa at 3 wt.% Na2O. Sodium aluminosilicate hydrate was the main activation product inside all samples, as confirmed by X-ray diffraction and thermal analyses. Acetic acid leaching test also proved that all LGS600-NaAlO2 mixtures represented Pb concentrations in leachates lower than the permissible level of characteristic leaching procedures, indicating the mitigation of environmental problems caused by these wastes.


Subject(s)
Industrial Waste , Sewage , Industrial Waste/analysis , Lead/analysis , Aluminum Oxide , Glass , Sodium Hydroxide/chemistry , Compressive Strength
20.
Carbohydr Polym ; 298: 120110, 2022 Dec 15.
Article in English | MEDLINE | ID: mdl-36241327

ABSTRACT

Aqueous sodium hydroxide solution is one of the simplest and most environmentally friendly solvents of cellulose. Regenerated cellulose/glucomannan blends were prepared from an aqueous sodium hydroxide solution, and the mechanical properties and structure of the blends were investigated. In addition, the noodle-shaped blends were sensory evaluated as food materials. The blends exhibited porous structures, which corresponded with high water and oil absorption. The strength and modulus of the blends were markedly low, probably due to the highly porous structure. The viscoelastic measurement indicated that cellulose and glucomannan existed in a rubbery state under wet conditions. The blends had a good oral sensation, probably derived from the remarkable porous structure, high water content, low strength and modulus, and rubbery state in wet conditions. The sensory evaluation suggested that the noodle-shaped blends can be used as a food material with a texture similar to capellini pasta.


Subject(s)
Cellulose , Water , Cellulose/chemistry , Mannans , Sodium Hydroxide/chemistry , Solvents/chemistry , Water/chemistry
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