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Phosphorus (P) in sediments plays an important role in shallow lake ecosystems and has a major effect on the lake environment. The mobility and bioavailability of P primarily depend on the contents of different P forms, which in turn depend on the sedimentary environment. Here, sediment samples from Baiyangdian (BYD) lake were collected and measured by the Standards, Measurements, and Testing procedure and Phosphorus-31 nuclear magnetic resonance spectroscopy (31P NMR) to characterize different P forms and their relationships with sediment physicochemical properties. The P content in the sediments varied in different areas and had characteristics indicative of exogenous river input. Inorganic P (334-916 mg/kg) was the dominant form of P. The 31P NMR results demonstrated that orthophosphate monoesters (16-110 mg/kg), which may be a source of P when redox conditions change, was the dominant form of organic P (20-305 mg/kg). The distribution of P forms in each region varied greatly because of the effects of anthropogenic activities, and the regions affected by exogenous river input had a higher content of P and a higher risk of P release. Principal component analysis indicated that P bound to Fe, Al, and Mn oxides and hydroxides (NaOH-P) and organic P were mainly derived from industrial and agricultural pollution, respectively. Redundancy analysis indicated that increases in pH lead to the release of NaOH-P. Organic matter plays an important role in the organic P biogeochemical cycle, as it acts as a sink and source of organic P.

Agriculture waste such as sugarcane bagasse (SCB) is composed mostly of cellulose, a very versatile natural biopolymer with well-established applications in many industries. The purpose of this study was to use combination treatment methods which include alkaline treatment and mild acid hydrolysis assisted with ultrasonication to extract cellulose nanofibers (CNFs) from sugarcane bagasse. Initially, the SCB fibers were treated with sodium hydroxide and aqueous hydrogen peroxide, a bleaching agent before subjected to mild acid hydrolysis followed by ultrasonication at 70% amplitude to defibrillate and disperse the fibers. The study focused on acid hydrolysis using mild sulfuric acid to the alkaline treated cellulose fibers extracted from SCB. The FESEM images of isolated CNFs exhibited diameter in the range 20–30 nm and length of up to several micrometers. This observation suggests that the combined treatment methods are highly effective in isolating CNFs from the plant biomass. Moreover, XRD analysis reveals the presence of peaks at 2θ of 15.2° and 22°, indicating cellulose type I with the crystallinity of 42%. Meanwhile, the FTIR spectra prove that individual CNF was successfully isolated due to the removal of non-cellulosic constituents. This result verifies that amorphous portions such as lignin and hemicellulose were completely removed. CNFs with long entangled network fibrils were successfully extracted from SCB through the combination of alkaline treatment and mild acid hydrolysis assisted with ultrasonication. The CNFs are expected to have high strength and aspect ratio that can be used as reinforced material in manufacturing nanocomposites.

This paper presents an experimental investigation on the durability properties of metakaolin (MK) and bottom ash (BA) blended geopolymer under different environmental exposure. The blended geopolymer concrete (GPC) was prepared with sodium based alkaline activators under ambient curing temperature. The concentration of sodium hydroxide used was 8 M. The ratio of sodium silicate to sodium hydroxide was kept as 2.0. The performance of blended geopolymer concrete was compared with conventional concrete (CC). The test results reveal that blended geopolymer concrete develops a better performance against sulphate and acid resistance. Also, MK-BA GPC shows enhanced performance over the conventional concrete in terms of sorptivity, rapid chloride and water absorption.

The concrete is expected to have features like high fluidity, self-compact ability, high strength, high durability, greater serviceability and long service life of concrete structures. rationalised and labour-saving benefits in manufacture and placement of concrete SCC is a highly designed concrete which addresses these needs. In this work the SCC samples with different percentage addition of ggbfs, fly ash and polypropylene fibres cured with Concentrated Sulphuric acid (H2SO4) and Sodium hydroxide (NaOH) at the period of 60, 80 and 120 days and it was tested under the temperature of 200 °C and 400 °C and it was tested for the compressive strength. Comparing the results with the samples without addition of polypropylene fibres (1% and 2%) there is a marked improvement in the compressive strength.

Herein, a facile wet-spinning strategy was used for the fabrication of mechanically strong all-chitin filaments from an aqueous NaOH solution using β-chitin nanofibers (β-ChNFs). It is hypothesized that to reach high mechanical performance it is important to preserve the crystalline structure of chitin during fabrication. To explore this possibility, β-ChNFs were disintegrated from squid pens by a mild procedure and showed a uniform diameter of 10-25 nm, length of a few microns, and a high aspect ratio of more than 200. An interesting finding was that gel-like β-ChNF filaments were directly formed in aqueous NaOH without using any organic or ionic agents. The gelation of β-ChNF

Ultrafiltration (UF) has been increasingly implemented in drinking water treatment plants; however, algae and their secretions can cause severe membrane fouling and pose great challenges to UF in practice. In this study, a simple and practical chemically enhanced backwashing (CEB) process was developed to address such issues using various cleaning reagents, including sodium hypochlorite (NaClO), sodium chloride (NaCl), sodium hydroxide (NaOH), sodium citrate, and their combinations. The results indicate that the type of chemical played a fundamental role in alleviating the hydraulically irreversible membrane fouling (HIMF), with NaClO as the best-performing reagent, followed by NaCl. Furthermore, a CEB process using a combination of NaClO with NaCl, NaOH, or sodium citrate delivered little improvement in the alleviation of membrane fouling compared with NaClO alone. The optimized dosage and dosing frequency of NaClO were 10 mg·L−1 two times per day. Long-term pilot-scale and full-scale experiments further verified the feasibility of the CEB process in relieving algae-derived membrane fouling. Compared with the conventional hydraulic backwashing without chemical involvement, the CEB process can effectively remove the organic foulants including biopolymers, humic substances, and protein-like substances by means of oxidization, thereby weakening the cohesive forces between the organic foulants and the membrane surface. Therefore, the CEB process can efficiently alleviate the algae-related membrane fouling with lower chemical consumption, and is proposed as an alternative to control membrane fouling in treating the algae-containing surface water.

Titanium and its alloys are commonly used implant materials. Once inserted into the body, the interface of the biomaterials is the most likely site for the development of implant-associated infections. Imparting the titanium substrate with high-aspect-ratio nanostructures, which can be uniformly achieved using hydrothermal etching, enables a mechanical contact-killing (mechanoresponsive) mechanism of bacterial and fungal cells. Interaction between cells and the surface shows cellular inactivation via a physical mechanism meaning that careful engineering of the interface is needed to optimse the technology. This mechanism of action is only effective towards surface adsorbed microbes, thus any cells not directly in contact with the substrate will survive and limit the antimicrobial efficacy of the titanium nanostructures. Therefore, we propose that a dual-action mechanoresponsive and chemical-surface approach must be utilised to improve antimicrobial activity. The addition of antimicrobial silver nanoparticles will provide a secondary, chemical mechanism to escalate the microbial response in tandem with the physical puncture of the cells.Hydrothermal etching is used as a facile method to impart variant nanostrucutres on the titanium substrate to increase the antimicrobial response. Increasing concentrations (0.25 M, 0.50 M, 1.0 M, 2.0 M) of sodium hydroxide etching solution were used to provide differing degrees of nanostructured morphology on the surface after 3 h of heating at 150 °C. This produced titanium nanospikes, nanoblades, and nanowires, respectively, as a function of etchant concentration. These substrates then provided an interface for the deposition of silver nanoparticles via a reduction pathway. Methicillin-resistant Staphylococcous aureus (MRSA) and Candida auris (C. auris) were used as model bacteria and fungi, respectively, to test the effectiveness of the nanostructured titanium with and without silver nanoparticles, and the bio-interactions at the interface.The presence of nanostructure increased the bactericidal response of titanium against MRSA from ∼ 10 % on commercially pure titanium to a maximum of ∼ 60 % and increased the fungicidal response from ∼ 10 % to ∼ 70 % in C. auris. Introducing silver nanoparticles increased the microbiocidal response to ∼ 99 % towards both bacteria and fungi. Importantly, this study highlights that nanostructure alone is not sufficient to develop a highly antimicrobial titanium substrate. A dual-action, physical and chemical antimicrobial approach is better suited to produce highly effective antibacterial and antifungal surface technologies.

Tongue epithelium is one of the most proliferative and regenerative epithelia in our body. However, tongue stem cell research is hampered partly by the lack of optimal animal models to study tongue injury, repair, and regeneration. Here, we establish a novel chemically induced tongue injury-recovery mouse model. Focal application of sodium hydroxide for a limited time led to the denudation of suprabasal layers, leaving the basal layer. Time course study revealed that tongue epithelial cells robustly proliferate over one week after the tongue injury. Importantly, we demonstrated that our novel mouse model could be employed in the lineage tracing of the tongue stem cells under the injury and repair process and further showed that tongue stem cells proliferate faster and generate larger clones in the injury condition than in the steady state condition. Our data indicate the development of a novel chemically induced tongue injury-recovery mouse model for tongue stem cell research, which will significantly facilitate the preclinical study for the pathogenesis and treatment of caustic ingestion.

In patients undergoing interventional or surgical coronary revascularization, subclinical hypothyroidism is common and associated with worse outcome, including the need for postoperative inotropic support. In isolated rat hearts with global ischemia/reperfusion, exogenous triiodothyronine (T3) reduces infarct size. Aim of this study was, to investigate whether or not exogenous T3 protects human myocardium from ischemia/reperfusion injury.Right atrial trabeculae from patients undergoing routine coronary artery bypass grafting were isolated and transferred to Tyrode's buffer. Electrically initiated (1 Hz) contractile stress (mN/mmAt baseline, contractile stress was comparable. T3 improved the cumulative recovery of contractile stress during reoxygenation from 41 ± 16 with NaOH to 55 ± 11% of baseline with T3, when given continuously in A or from 52 ± 13 with NaOH to 63 ± 11% of baseline with T3 when given just before and during reoxygenation in B. The ratio of mitochondrial complex I matrix arm to membrane NADH:ubiquinone oxidoreductase subunits (NDUF)V2 to NDUFA9 was reduced, reflecting increased complex I activity.T3 increases contractile recovery of human right atrial trabeculae from hypoxia/reoxygenation.

Pure LTA zeolites of high crystallinity have been synthesized from coal fly ash (CFA) by utilizing a method of microwave and ultrasound collaborative activation (MUCA) in situ for the first time. Compared to the activation method of only microwave or ultrasound, the MUCA have more efficient ability to dissolve silica-aluminum species from CFA while avoiding the digestion of other impurities, greatly reduced the energy consumption. While the liquid-solid ratio (LSR) of sodium hydroxide solution to CFA was 10 mL/g, the molar conversion rates of silicon and aluminum were 70.26% and 68.03%, respectively. Furthermore, with different LSR, pure LTA zeolite could be synthesized by adjusting the ratio of Si/Al. The CFA used in this paper contains Fe2O3 of about 12 wt percentage, and there have found almost no element of iron existing in the LTA zeolite products, indicating that the method of MUCA is suitable for the preparation of high purity zeolite. Finally, according to the mechanism of crystallization-dissolution-recrystallization, the morphology of LTA products could be well tuned by adjusting parameters such as LSR or crystallization time. The maximum BET surface area was 474 m2/g without additional calcium ion exchange steps by direct using of municipal water instead of deionized water, and the maximum CO2 adsorption capacity was 1.96 mol/g under 0 ℃. The mesoporous LTA zeolite also have been prepared just through the adjustment of crystallization time without addition of any other templates, the intramesopores of about 17 nm made greatly improvement in catalytic cracking of 1,3,5-tri-isopropylbenzene which is inaccessible to the conventional LTA micropores, and the conversion rate of 1,3,5-tri-isopropylbenzene reached to 25.40% as well as 11.05% of the selectivity of secondary cracking product benzene.

This study aimed to evaluate the properties of cellulose nanofibers (CNFs) with different hemicellulose contents and cellulose II polymorphs. A link was found between these polysaccharides and the properties of CNFs. A decrease in crystallinity (from 69 to 63%) and changes in the crystalline structure of cellulose subjected to an alkaline environment were observed, promoting the partial conversion of cellulose I to cellulose II (from 2 to 42%) and preventing CNFs production at NaOH concentrations higher than 5%. Most treatments showed pseudoplastic fluid behavior, except for the 10% NaOH treatment over 2 h, which showed Newtonian fluid behavior. The quality index of the reference CNFs (TEMPO-oxidized) was the highest (80 ± 3), followed by that of the 5% NaOH-treated (68 ± 3 and 22% energy savings compared to the untreated sample), and the untreated (63 ± 3) samples; and the 10% NaOH treatments had quality indices of 51 ± 3 and 32 ± 1, respectively.

Most of the series of nanochitins have been produced by the break-down process. In this study, chitin nanoparticles were prepared by a bottom-up process. Chitin was treated with sodium hydroxide to obtain an alkaline chitin aqueous solution. The alkaline chitin was regenerated by neutralization and then vigorously stirred to obtain chitin nanoparticles. The average particle size of the chitin nanoparticles was 7 nm. The individual particles were stably dispersed in water. Chitin nanoparticles had lower crystallinity than the raw material chitin and the surface of the chitin nanoparticles regenerated in water were presumed to be hydrophilic. The low crystallinity and the high hydrophilicity of the surface contributed to the high dispersibility of the chitin nanoparticles in water. Chitin nanoparticles had higher heat resistance than the raw material chitin, suggesting a large change in the higher-order structure associated with dissolution and subsequent regeneration of chitin. Since chitin nanoparticles interact with each other less than chitin nanofibers produced by mechanical treatment, the viscosity of nanoparticles was smaller than that of nanofibers. Therefore, it can be prepared at a high concentration. In addition, the chitin nanoparticles can be easily redispersed in water after being concentrated by centrifugation.

Adsorption is a simple and efficient phosphorus removal method used to control the eutrophication of water bodies. A simple and gentle atmospheric pressure hydrothermal method by adjusting the dosage of ammonium chloride and sodium hydroxide was used to synthesize amorphous, monoclinic, and tetragonal zirconia nano-powders with high specific surface areas (383.91 m2/g, 330.01 m2/g, and 234.36 m2/g) and particle size of about 40 nm for phosphate adsorption. When pH = 6.3, the phosphate adsorption capacity of the amorphous monoclinic phase and the tetragonal phase respectively reached 102.58 mg P/g, 68.11 mg P/g, and 37.25 mg P/g and the adsorption process of the three crystal forms of zirconia powders conformed to the Langmuir adsorption model. In the first 2 min of rapid adsorption, amorphous zirconia completed 76.23% of the adsorption process and the monoclinic phase also completed more than 60%. The adsorption process of the three crystal forms of zirconia was completed within 240 min and conformed to the pseudo-second-order kinetic model. Their adsorption characteristics of the three crystal forms of zirconia decreased with the increase in pH. While the pH was above than the isoelectric point of the solution, the adsorption capacity was significantly reduced. The large specific surface area and high hydroxyl content of the zirconia nano-powder made a great contribution to the adsorption process.

This study aims to develop the alkali activated slag-fly ash concrete (AASFC) using precious slag (PS) ball as the fine aggregate. The slag-fly ash proportion, sodium silicate/sodium hydroxide (SS/SH) ratio and sodium hydroxide concentration are the prime variables. The fresh concrete properties like workability, setting time and the hardened concrete properties of AASFC developed under ambient curing were analyzed and similar way by replacing with fly ash (FA). The sodium hydroxide concentration of 8 M, 10 M and 12 M, SS/SH ratio of 1.0, 1.5 and 2.0, alkaline liquid to binder ratio of 0.35 and variation in slag-fly ash proportion as major inputs for mix design. The test results showed that, the fresh state of AASFC blend has a shorter setting time of 12–16 min, because of calcium mineral from the FA, the workability and setting time of AASFC mix was enhanced by the addition of the tri-sodium phosphate as a retarder. At the higher SS/SH extent, the workability and setting time exaggerated, whereas the increased FA content and sodium hydroxide concentration had a greater influence on the fresh state of concrete. Also, the sodium hydroxide concentration, SS/SH ratio and slag-fly ash proportion are the most inducing parameters on the workability, setting time and strength parameters of AASFC.

Zinc ferrite (ZnFe2O4) nanomaterial can be facilely and conveniently synthesized via the co-precipitation method from aqueous Zn2+ and Fe3+ salt solutions using sodium hydroxide as the precipitant. However, zinc hydroxide is amphoteric and can be soluble at low and high pH values; therefore, the study on pH for simultaneous precipitation of Fe3+ and Zn2+ to achieve pure ZnFe2O4 spinel is essential. In the present study, we elaborate a theoretical equation expressing the relationship between the zinc concentration in complex formation and pH value in the co-precipitation step. Since then, we synthesized ZnFe2O4 spinel and analyzed the products via various techniques such as thermoanalysis (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–Vis spectra to investigate the appropriate pH for simultaneous precipitation of Fe3+ and Zn2+. The results indicate that in a wide range of pH values, from 7 to 12, ZnFe2O4 single-phase spinel ferrite structure is formed after calcination of the precipitate at 800 °C, the average particle sizes (SEM, nm) of ZnFe2O4 samples are in the range of 59.5 nm–85.5 nm (but is non-linear change), and their bandgap values are similar, around 1.96 eV. However, the unwanted appearance of α-Fe2O3 phase, the shifting in peak position and the decrease in intensity in the XRD pattern of the spinel products synthesized at pH of 6 and 13, respectively, reflect that the stoichiometric ratio of Zn2+ to Fe3+ in the spinel products is not achieved to 1:2. Such results provide a fundamental basis for choosing the appropriate pH in synthesizing ZnFe2O4 nanoparticles with orientationally structural and optical characteristics.

Many species of bacteria interact on the human skin to form a certain microbiome. Delftia acidovorans, a bacterium detected from human skin, inhibits the growth of S. epidermidis, a dominant bacterium of the human skin microbiota. Here, we show that ammonia secreted by D. acidovorans inhibits the growth of S. epidermidis by increasing the pH value of the medium. The pH value of D. acidovorans culture supernatant (CS) was higher than that of the medium without culture. The inhibitory activity of the D. acidovorans CS against the growth of S. epidermidis was decreased by neutralization with hydrochloric acid. Genes encoding enzymes related to ammonia production were found in the D. acidovorans genome. Moreover, the D. acidovorans CS contained a high concentration of ammonia. The addition of ammonia to S. epidermidis culture led to an increase in the reactive oxygen species (ROS) production and inhibited S. epidermidis growth. The addition of sodium hydroxide also led to an increase in the ROS production and inhibited S. epidermidis growth. The inhibitory activity of ammonia and sodium hydroxide against S. epidermidis growth was suppressed by malonic acid, an inhibitor of succinate dehydrogenase in the tricarboxylic acid (TCA) cycle, and N-acetyl-l-cysteine, a free radical scavenger. These findings suggest that D. acidovorans secretes ammonia and alkaline stress inhibits the growth of S. epidermidis by inducing TCA cycle-triggered ROS production.

The traditional sodium desulfurization process for waste lead-acid batteries is beneficial to the environment; however, it is limited by poor economic viability as the cost of desulfurizer is much higher than the value of desulfurization by-products. This study proposes a new closed-loop pre-desulfurization process for lead paste, which consumes only lime as the indirect desulfurizer, produces sodium sulfate as a by-product, and regenerates sodium hydroxide as the direct desulfurizer. The concentration of prepared sodium hydroxide reached 2.57 mol/L when the reaction was conducted at room temperature for 2.0 h, with a sodium oxalate: calcium oxide molar ratio of 1:1.3, a CaO: water mass ratio of 1:6, and magnetic stirring at 600 rpm. Cost estimation and economic analyses were also conducted. The cost of lead paste generated by this new pre-desulfurization process was 37.62 dollars/ton lower than traditional high-temperature smelting, and 44.42 dollars/ton lower than direct sodium pre-desulfurization. Thus, this process provides a practical and feasible clean recycling method for waste lead-acid batteries with significant environmental and economic benefits.

Environmental benefits and amazing performance can be obtained by utilizing palm oil fibres and kenaf fibres which illustrate colossal potential in fibre reinforced composites. An investigation has been made to determine the effects of alkaline treatment on water absorption and swelling behaviour of palm oil fibre composites as well as kenaf fibre composites. Untreated and treated natural fibres and were prepared in random orientation with different volume fraction of palm oil fibres and kenaf fibres; 30%, 40%, and 60. All the treated fibres were treated with 1 w/v% and 5 w/v% of sodium hydroxide concentration. Water absorption test was performed by immersing the sample in the distilled water periodically measuring the sample weight. Thickness swelling test was carried out by measuring the thickness of the specimens before and after soaking in the distilled water within certain period of time. All specimens were observed under Scanning Electron Microscope (SEM) to study the fibre morphology. TPOF_30_5SH achieved the least percentage of water absorption (1.44%) when it was compared with the UPOF_30 and TPOF_40_1SH. UPOF_60 shows the highest percentage of thickness swelling (8.96%). TPOF_30_5SH and TPOF_40_5SH show reduction of water absorption when they were compared with UPOF_30 and UPOF_40 respectively. All the treated kenaf fibre composites with 5 w/v% sodium hydroxide concentration such as TKF_30_5SH, TKF_40_5SH and TKF_60_5SH show improved result of thickness swelling. Materials covering the surface of palm oil fibres and kenaf fibres were more effectively removed with 5 w/v% sodium hydroxide than by treatment with 1 w/v% sodium hydroxide while observing under SEM.

Herein, we report an efficient, environmentally friendly and stable catalyst development to hydrogen evolution from sodium borohydride hydrolysis. For this purpose, Ruthenium complex catalyst successfully fabricated via 5-Amino-2,4-dichlorophenol-3,5-ditertbutylsalisylaldimine ligand and RuCl3·H2O salt. Ru complex catalyst was identified with X-Ray Diffraction Analysis, Infrared Spectroscopy, Elemental Analysis, Transmission electron microscopy, Scanning Electron Microscope and Brunauer-Emmett-Teller Surface Area Analysis. According to the analysis results, it was confirmed that Ru complex catalyst was successfully synthesized. Ru complex was used as a catalyst in NaBH4 hydrolysis. The kinetic performance of Ru complex catalyst was evaluated at various reaction temperatures, various sodium borohydride concentration, catalyst concentration and sodium hydroxide concentration in hydrogen evolution. The apparent activation energy for the hydrolysis of sodium borohydride was determined as 25.8 kJ mol−1. With fully conversion, the promised well durability of Ru complex was achieved by the five consecutive cycles for hydrogen evolution in sodium borohydride hydrolysis The hydrogen evolution rates were 299,220 and 160,832 mL H2 gcat−1 min−1 in order of at 50 °C and 30 °C. Furthermore, the proposed mechanism of Ru complex catalyzed sodium borohydride hydrolysis was defined step by step. This study provides different insight into the rational design and utilization and catalytic effects of ruthenium complex in hydrogen evolution performance.

In this analysis, the alkaline activators prepared by mixing sodium hydroxide and sodium silicate and rice husk ash (RHA) were used as the source material in geopolymer concrete. As fibre reinforcement in geopolymer concrete, basalt fibres (B.F.s) were used. Silica luxurious RHA and alumina luxurious B.F.s proved the best mishmash for rigid pavement abrasion resistance. The ratio of sodium silicate (sdsi) to sodium hydroxide (sdhd), alkaline activator to binder content was maintained as 2.0 and 0.4 respectively, the concentration of sodium hydroxide was maintained as 14 M, the fluidity of geopolymer concrete was improved by superplasticizer, and RHA used was 500 kg/m3 in MRM (control mix which is rice husk ash based geopolymer concrete without basalt fibres). B.F.s were used as 1, 5, 10, 15, 20, and 25 per cent by weight of RHA in the MB1, MB5, MB10, MB15, MB20 and MB25 combinations, and the results of B.F.'s blends were compared with the MRM. The results showed that, relative to the control mix and all other mixes, the impact strength in mix MB10 was high. In contrast to the MRM control combination, the seven, twenty-eight, and ninety-day impact strength of MB10 showed a substantial increase of more than 88, 89, and 92 per cent, respectively.

Dyes derived from coconut (Cocos nucifera) husk have materialised as an important substitute to synthetic dyes. However, better extraction techniques are needed to leach out the natural colourants from this plant. The influence of sodium hydroxide (NaOH) concentration (0.2 to 0.8 M) and time of extraction (2 to 10 min) on the maximum extraction yield of natural dye from the mesocarp and exocarp of C. nucifera have been studied. The results indicate a significant (p

The present study is an attempt to examine the feasibility of developing a sustainable self-compacting concrete (SCC) made with geoploymer binder and recycled aggregate. The study explores the effects of four sodium hydroxide (SH) molarities (8 M, 10 M, 12 M and 14 M) on the fresh properties of self-compacting slag-based geopolymer concrete. Eight slag-based geopolymer concrete mixtures were examined. These mixes are divided into two groups: GPN group in which the mixtures are made with natural aggregate (NA) and GPR group in which the mixtures are made with recycled aggregate (RA). Each group includes four mixes made with the four mentioned SH molarities. The mixtures were examined for its flowability, passing ability, viscosity and segregation resistance and the results were tested against the EFNARC recommendations for SCC. It was concluded that recycled aggregate and the molarity of sodium hydroxide affects the fresh properties of SCC. But, developing self-compacting slag-based geopolymer concrete that meets the limits of EFNARC is feasible.

This research included synthesis of heterocyclic compounds, in the first step where the compound [M1] was prepared from the reaction of chloroacetyl chloride with the nitrogenous base uracil using a basic medium. Compound [M1] then were converted into compound [M2] by reacted with hydrazine hydrate (95%) in absolute ethanol using sodium hydroxide (KOH). Schiff bases [M3-M9] were prepared from the reaction of the compound [M2] prepared in the second step with some substitutes of benzaldehyde in absolute ethanol. Tetrazole derivatives [M10-M16] were prepared from the reaction of Schiff bases [M9-M3] with sodium azide in tetrahydrofuran(THF) as a solvent. After purifying the product, the synthetic compounds were diagnosed with some spectral methods such as [UV], [FTIR], [1H NMR] and [13C-{1H}NMR], in addition to determining the melting and purity levels of the prepared compounds and monitoring the progress of the reactions using TLC thin layer chromatography. The effect of some prepared compounds on the growth of two types of bacterial isolates, known to be resistant to antibiotics, one negative for Gram stain [Gr-ve], which is Pseudomonas aeruginosa, and the second positive for Gram stain [Gr + ve], which is Staphylococcus aurous, were used antibiotics Amoxicillin and Ampicillin. Some of the prepared compounds showed high inhibitory efficacy against the used bacteria in addition, the conformation of prepared compounds at the lower energy level were studied.

The behavior of concrete in the form of an adhesive made with activated silicon and aluminium in a highly alkaline solution is investigated in this study. Research on concrete based on low calcium fly ash is widely used. The fly ash with high calcium content can also be suitable as a base material for producing geopolymers. In this investigation, the exact ideal substitution amount of GGBS: Fly Ash for PPC concrete mix was determined to be 60:40. For different sodium hydroxide and sodium silicate chemical ratios in the concrete mix, different results were produced. This research adds to our understanding of the performance of various strength concretes and GGBS as partial cement substitutes. Mechanical strength and durability properties and acid attack were discovered in the GGBS and Fly Ash concrete mix. Sodium Silicate and sodium hydroxide have been discovered to affect various combinations as well as strength and durability.

During open-pit mining operations of phosphates, huge volume of rocks by products are accumulated and deposited in the mine site. The aim of this paper is to investigate the use of marls as an only aluminosilicate precursor to produce alkali-activated geopolymers. Marls from Moroccan phosphate basins are composed of carbonates, quartz and clays. Raw marl was dried, grinded and calcined at 750 °C. After the heat treatment, the calcined powder was activated using a strong alkali solution, which is a mixture of sodium hydroxide and sodium silicate with a ratio of 0.5. The physical and chemical properties of raw and calcined marls were analyzed using TGA, BET, Pycnometer, particle size analyzer, XRF, XRD, FTIR and SEM. Furthermore, elaborated geopolymers were characterized after 7 and 120 days of curing at ambient temperature using XRD, XRF, TGA, SEM and the mechanical behavior was tested by measuring the compressive strength. The results showed the formation of both; C-A-S-H (Calcium aluminum silicate hydrate) and N-A-S-H (Calcium aluminum silicate hydrate) gels with a compressive strength of 38 MPa confirming that marls from phosphate extraction by-products could be used as a source for the elaboration of geopolymers.

Keeping in view of the hazardous effects of production of Ordinary Portland Cement (OPC) on the environment, it is necessary to minimize the usage of OPC and subsequently replace it by the alternative materials which possess the binding properties. One such attempt led to discovery of geopolymer concrete. In present study, Alumina Refinery Residue (ARR) and slag from iron industry (GGBFS) are the two binder materials used in the ratio of 25:75 (ARR: GGBFS) along with the combination of Sodium Hydroxide and plagioclase-based alkali activator for initiating polymerization reaction. Present study focuses on evaluation of performance of geopolymer concrete in terms of Compressive Strength and Acid Durability Factor. Test results revealed that 28 days compressive strength of geopolymer concrete was found to be 38.37 N/mm2 and that for NCC was 35.32 N/mm2. It is also observed that the percentage weight loss and strength loss after 120 days of immersion of the specimens in 10% HCl solution, was found to be 11.133% and 13.526% for GPC and that for NCC was found to be 13.504% and 21.347% respectively. Results of Acid Durability Factor proved that GPC specimens were found to perform 7.82 times better than NCC specimens. Further, Scanning Electron Microscope technique was used to analyze microstructure of both GPC and NCC specimens. Micro analysis results also showed that GPC specimens prove to be better than NCC specimens. The present study significantly determines the performance of GPC specimens produced by the combination of Sodium Hydroxide and Plagioclase based activator for initiating polymerization reaction. Generall, In this study, sodium/potassium based silicate compound in the alkali activator part is completely replaced by Plagioclase based activator (in the powder form) in order to have better mechanical, durable and microstructure properties, resulting to a economic mix for massive applications.

Bisphenol-A (BPA) is a common plasticizer that has been considered a chemical of concern due to its endocrine disruption potential. In this sense, this paper aimed to investigate the adsorption of this contaminant onto commercial organophilic clay named Spectrogel® as means of water remediation. For this, characterization techniques were carried out before and post-process to identify any major alterations to the adsorbent due to BPA uptake. A statistical central composite rotational design (CCRD) technique was performed for process optimization. The impact of adsorbent dosage mass (0.128–1.472 g.100 mL−1, solution concentration (0.064–0.736 mmol/L−1) and particle diameter (0.28–1.0 μm) on the adsorption capacity was analysed. It was defined 0.064 g of adsorbent dosage and an average particle size of 0.855 μm as optimum conditions, in which a 0.193 mmol.g−1 (44.060 mg.g−1) adsorption capacity was obtained. Static adsorption assays showed that the kinetics better followed the external mass transfer resistance model, whilst the isotherm data obtained at 15 and 25 °C were well expressed by the Freundlich model and at 40 and 55 °C by the D-R model, achieving a maximum adsorptive capacity of 0.4 mmol.g−1 (91.316 mg.g−1). The thermodynamic parameters reflected a spontaneous and endothermic process. Furthermore, numerous eluent solutions were tested to assess the regenerability of the adsorbent and sodium hydroxide displayed the best desorption capacity (77.8%). The Spectrogel® clay has shown to be very promising as an alternative adsorbent in the remediation of water contaminated with BPA.

The present study was performed to find out the structural similarity of hydroalcoholic extract of abutilon indicum and standard non-steroidal anti-inflammatory drugs (NSAIDs) using various analytical and chromatography techniques. The characterization was performed by fourier transform infrared spectrophotometer (FTIR), UV–Vis spectrophotometer, thin layer chromatography (TLC), and reverse-phase high phase liquid chromatography (RP-HPLC). Paracetamol and aceclofenac were used as standard NSAIDs. The FTIR peaks obtained for abutilon indicum were at wavenumber 2933.81, 2359.61, 1459.90, 762.73, 1640.09, 1559.74, and 3253.75 cm−1 confirms the presence of aromatic acid, hydroxyl group, and carboxylic groups. In addition, the UV–Vis profile showed peaks at 274 nm and 244.5 nm for abutilon indicum in methanol and sodium hydroxide respectively. Further, the TLC method showed the retention factor (Rf) values at 0.38 and 0.36 for abutilon indicum which were almost similar to Rf values of paracetamol and aceclofenac. The peak and retention time from RP-HPLC for abutilon indicum showed the values at 3.640 and 2.603 that were in accordance with standard NSAIDs. Thus, this study can give an insight that abutilon indicum does contain structures similar to paracetamol and aceclofenac which are responsible for their analgesic activity.

Insolubility of cellulose in common solvent had been a challenge in generating cellulose hydrogels. In the present work, hydrogels from sugarcane bagasse extracted cellulose and modify with synthetic polymer, poly (vinyl alcohol) (PVA) and cross-linker, glutaraldehyde (GA) was synthesize. Cellulose was isolated from sugarcane bagasse via pre-treatment with 4 vol% sulphuric acid (H2SO4) and 10 wt% sodium hydroxide (NaOH) solution. The cellulose extracted was dissolved in ZnCl2/CaCl2 solution at 65 ℃ to fabricate self-standing cellulose hydrogel without cross-linker. Another cellulose hydrogel was generated and immersed into 5 wt% GA solution to cross-link the cellulose chains. To improve the stability and swelling properties of cellulose, PVA was introduced into the hydrogel by using GA to cross-link cellulose chains with PVA chains. The resulting hydrogels were characterized with Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and solid state 13C Nuclear Magnetic Resonance (NMR) spectroscopy for structural determination. Three self-standing cellulose-based hydrogels, including regenerated cellulose (RC), GA cross-linked cellulose (C-GA), followed by PVA and GA cross-linked cellulose (C-GA-PVA) were successfully generated from ZnCl2/CaCl2 dissolution system and each hydrogel possessed different physical aspects. The occurrence of chemical cross-linking reaction between cellulose, GA and PVA was further evidenced by the data analyzed from ATR-FTIR and NMR spectra. The swelling degree of hydrogels generally increase after the addition of PVA and GA into cellulose suspension, showing 52 % (RC), 80 % (C-GA) and 135 % (C-GA-PVA). C-GA-PVA possessed the best swelling capability and potential for possible application as water reservoir in agriculture.

In this paper, CeVO4 nanostructures were produced with controlled hydrothermal method using hydrazine, cerium nitrate, and ammonium vanadate as reactants. Reaction control was performed utilizing hydrazine and ethylenediamine as new reactants. Other effective parameters such as solvent and surfactant were also carefully studied and optimized. The products were then identified through XRD, EDS, FTIR, FESEM, and BET analyses. FESEM results showed that by adjusting the concentration of ethylenediamine, hydrazine, and PVP surfactant, a rod-shaped morphology with suitable porosity could be created. Due to the high potential of CeVO4 in electrochemical processes, it was first employed for electrochemical storage of hydrogen. The amount of hydrogen storage in nanostructures produced with rod-shaped morphology was about 2575 mAh/g, which is very significant compared to products obtained with sodium hydroxide with spherical morphology.

Here a starch and starch hydrogel nanocomposite and superabsorbent cotton fabric was fabricated and characterized. The optimized starch hydrogel nanocomposite was synthesized by using 0.008 M potassium permanganate, 0.7 g starch and 0.6 M sodium hydroxide at 50–55 °C. potassium permanganate as a strong and inexpensive oxidizing agent were used to potentially nano cross-link the starch molecular chains and graft the starch to cellulose molecular chains along with synthesizing manganese dioxide nanoparticles (MnO2) to further obtain antibacterial, antifungal and photocatalytic properties. The stability of products in water and the water absorption indicated the highest water content of 800% for the optimum sample. The same materials and conditions were also applied to the cotton fabric to produce a superabsorbent fabric. The simple one-step synthesis procedure, in-situ production of nanoparticles, cost-effectiveness and having desired features including photocatalytic, antibacterial properties of 93% against S. aureus, and biocompatibility make the starch hydrogel nanocomposite a suitable candidate for various applications such as agriculture, medical, textile engineering and water treatment.

The possible impact of bio and electrochemical reactions during pretreatment of rice straw using solvents, sulphuric acid (SA), ammonia (AM), sodium hydroxide (NA), and distilled water (W) was investigated. The total volatile fatty acids (tVFAs) of 163.48 ± 10.49 mM in the electrochemical pre-treatment in the presence of sodium hydroxide (ENA) followed by sulfate-reducing bacteria (EBA) (140.88 ± 0.07 mM) indicating the involvement of electrolytic breakdown of lignocellulosic biomass. The hydrogen production of 0.224 ± 0.05 and 0.218 ± 0.10 mM/g of the substrate was found in the ENA and anoxic sodium hydroxide pre-treatment (CNA) respectively. There was no detectable gasification in SA and AM electrochemical pre-treatments. The major advantage of the electrochemical process is the formation of acetic acid at a lower temperature, whereas processes like autohydrolysis form it at high temperatures during stream explosion pretreatment. The hydrogen production of 1.26 mM/g was found from anoxic hydrolysate pretreated (ECP) rice straw. The SEM and FTIR analysis show distortion of outer layers of biomass in the electrochemical pretreatment (ECP) system, which improved its accessibility towards enzymes for value-added product recovery.

Carbon nanotubes (CNTs) are promising for realizing ultrafast membranes with implications to molecular separations and beyond. However, it is a big challenge to harness the potential of CNTs for designing scalable yet high-performance membranes. Here we systematically explore the role of loading and vacuum-assisted alignment of CNTs for improving the desalination performance of polyamide (PA) based thin-film composites. To rule out the dispersion instability issues, we focused on carboxylated single-walled CNTs (SWCNTs) commercially available in the market. After applying a pre-treatment for cleaning, we deposited SWCNTs on porous polysulfone supports by vacuum filtration and coated a PA layer on top via interfacial polymerization. Morphological assessments supported by polarized Raman microspectroscopy allowed the quantification of SWCNT alignment. At an optimum SWCNT loading, which we found critical for alignment, the water permeability of resulting membranes significantly improved without compromising NaCl selectivity. Also, we achieved an improved boric acid selectivity, arguably owing to the hydrophobic nature of nanotube channels. Moreover, nanotubes promoted resistance against chlorine degradation and improved mechanical strength. Vacuum deposition is instrumental for infiltrating SWCNTs into the support layer, but a mat layer forms between the support and PA layers when SWCNT loading exceeds the limit that the support pores can accommodate. Given that we use ordinary SWCNTs and a scalable methodology (vacuum-assisted infiltration), the developed membranes are promising for practical applications. © 2021 Elsevier Ltd

Immobilization of Escherichia coli (E. coli) on commercial activated charcoal was enhanced by mild chemical treatment coupled with curli production from E. coli. The chemical used to treat the activated charcoal were sodium hydroxide, hydrochloric acid, ammonium hydroxide, and acetic acid while nickel (II) chloride was used to promote the production of curli. Characteristics of the activated charcoal before and after chemical treatments were analyzed including its surface properties, pore size, and crystalline structure. The immobilization of E. coli was enhanced greatly after sodium hydroxide treatment which gave rise to more than 120 % cell immobilized compared to the untreated activated charcoal which was mainly attributed to the larger size of macropore, surface area, and pore volume. Curli were produced by the induction of nickel (II) chloride and further enhanced the cell immobilization by at least 50 %. Overall, the combine strategy enhanced cell immobilization by more than 160 %. The resulting biocatalyst from the enhanced cell immobilization managed to be reused up to 10 cycles for the enzyme cyclodextrin glucanotransferase expression while retaining up to 60 % of the enzyme’s initial activity.

This work aims to improve the electrospinability and antibacterial activity of chitosan (CS) - based nanofibers. Three approaches consisting of reducing molecular weight of CS by NaOH hydrolysis (HCS), blending with two carrying polymers (polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA)) and incorporating with in-situ synthesized silver nanoparticles (AgNPs) were integrated simultaneously for the first time to fabricate the HCS-AgNPs/PVP/PVA multicomponent nanofibers. The electrospinning parameters were optimized to obtain the smooth and uniform nanofibers without beads of both HCS/PVP/PVA and HCS-AgNPs/PVP/PVA systems. The presence of in-situ AgNPs in the multicomponent blends gives the better electrospinning performance and the lowest fiber diameter of 139 nm. In addition, the thermal properties, thermal stability and crystallinity index of both nanofibers also increased with increasing HCS or HCS-AgNPs fractions. Finally, the best antibacterial activity of HCS/PVP/PVA and HCS-AgNPs/PVP/PVA nanofibers against E. coli was found to be 74.4% and 99.9%, respectively. The significant enhancement in bactericidal activity of HCS-AgNPs/PVP/PVA nanofibers against E. coli is due to the synergistic properties of HCS/PVP/PVA blends and AgNPs. Both nanofiber mats displayed the excellent structural stability in moisture environment for at least 7 days. Therefore, the HCS-AgNPs/PVP/PVA nanofibers could be a potential material for applying in the medical purpose.

Surfactant based microwave irradiated and alkaline medium involving wet chemical method was adopted to prepare CdO nanostructures. The phase evaluation of prepared and annealed CdO nanostrucutures has been analyzed by XRD and FTIR. The average size of the crystallite was estimated to be 54 nm for the NH4OH reagent and 60 nm for the NaOH reagent in the assisted synthesis. Specific surface area, lattice parameter, X-ray density, dislocation density, microstrain, texture coefficient and Williamson Hall have been calculated from the XRD profile. UV transmittance and the K-M plot of DRS and PL spectra were used to examine the optical properties of CdO nanostructures. The spherical and rod-like structures of CdO prepared with strong and weak alkaline medium have been recorded through SEM and TEM micrographs. The four-step process of hydration, intermediate formation, metal hydroxide formation, and metal oxide formation confirms that the experiment in the presence of 0.1 M sodium hydroxide results in rod-shaped nanostructures.

High strength ambient cured alkali-activated cement was developed from original Class-F (ASTM) fly ash using 1:2.5 mass ratio of 16 molar sodium hydroxide and sodium silicate liquid activator with solution to solid binder ratio of 0.36 for in-situ cast application. Graded strength of high, medium and low in the range of 60–103, 30–56 and ≤ 20 MPa were obtained using mono-component original fine, medium and coarse sized fly ashes respectively. The inclusion of 35 wt% GGBS in the medium sized Class-F fly ash improved the strength from 45 MPa to 60 MPa while 100% GGBS showed higher strength of 81 MPa. Chemically, CaO/SiO2 ratio in the composition influenced the fresh and hardened properties of alkali-activated fly ash/GGBS cements. For instance, in the Class-F fly ash (Si/Al=1.55-1.99) based compacts with CaO/SiO2 ratio ≤ 0.03, the strength improved with increasing atomic Al/(Na + K) ratio. Conversely strength decreased with increasing Al/(Na + K) ratio in bi-component fly ash and GGBS based alkali-activated cements where CaO/SiO2 ratio is higher in between 0.17-0.75. Interestingly Si-dissolution from subcrystalline silica or fine quartz from mechanically activated Class-C fly ash did not improve strength. Lignite ash with high specific surface area as obtained in low temperature combustion did not react with high pH alkaline solution indicating need for vitreous aluminosilicate glass. X-ray diffraction and attenuated total reflectance Fourier transform infrared spectroscopic analyses show that plagioclase and C-S-H were the reaction products responsible for strength gain in ambient cured alkali-activated fly ash/GGBS cements.

Since being discovered, alkali/urea has been widely used in the dissolution of natural polysaccharides and the preparation of functional materials such as hydrogels, fibers, films and nanoparticles. This work will focus on verifying the structural stability, homogeneous degradation and deacetylation of chitin in alkali-soluble systems. The chitin was dissolved in NaOH/urea solution and stored at different temperature. At the specific time, the structure, viscosity, acetylation degree (DA) and biocompatibility of chitin and prepared chitosan were determined. The results indicated that dissolution process did not affect the structure and bioactivity of chitin. However, with the increase of storage time and temperature, chitin undergone significant homogeneous deacetylation (DA from 99.5% to 33.2%) and degradation (viscosity from 9284 cP to 1538 cP), accompanying by changes in crystalline structure and thermal stability. Moreover, the processed chitins were no-toxic for the biomedicine applications. This work will provide new ideas for the application of alkali-soluble systems.

It is of great practical significance to manufacture ceramic membranes with good reusability. We used a macromolecular gel network for in situ enhancement of a reticulated skeleton ceramic (RSC) membrane. The prepared RSC membranes were firstly characterized to determine their physical and chemical properties. The sample calcined at 1400 °C has a porosity of 41.66 %, a pore size of 0.34 μm, a mechanical strength of 4.53 MPa, and a permeability of 63.92 L m−1 h−1 bar−1. This membrane can effectively reduce the content of total organic carbon (TOC) (80 %) and calcium ion (>85 %). In addition, the flux of RSC fouled by alginate, calcium ions, or their mixture is effectively recovered by simple chemical rinsing using sodium hydroxide and ethylenediaminetetraacetic acid.

This research focused on the elaboration of geopolymers based on natural Moroccan perlite at room temperature by adding calcined Moroccan kaolinic clay as a source of reactive alumina. The amount of calcined kaolinic clay ranged from 0 to 50%. A mixture of sodium silicate and sodium hydroxide was used as an alkaline activator. The calcined kaolinic clay effect on the physicochemical and microstructural properties of synthesized geopolymers was evaluated using several analytical techniques, such as compressive strength tests, P-wave velocity, density and porosity, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The outcome showed that the 10% calcined kaolinic clay addition leads to improvement in the physicomechanical properties and results in a geopolymer at room temperature with interesting physico-chemical characteristics at the age of 28 days. Incorporation of more than 10% calcined kaolinic clay favored the zeolites appearance (phillipsite and Na-faujasite) in the geopolymer matrix forming a heterogeneous microstructure, which led to the decrease of the mechanical properties of the synthesized geopolymers. These properties support the use of synthesized geopolymers as a good substitute for conventional construction materials (natural stones, stabilized soils, fired clays, and cement mortars).

The behavior and mechanism of Li leaching from lithium aluminum silicate glass-ceramics which can be used as a secondary source of Li using aqueous NaOH solution was investigated. The Li leaching efficiency is increased with increasing concentration of NaOH, specific surface area, and reaction temperature. When leached under optimum conditions, 2 mol/L NaOH, 53 μm particle undersize, 1:10 solid/liquid ratio, 250 r/min stirring speed, 100°C reaction temperature, 12 hr, the Li leaching efficiency was approximately 70%. However, when the leaching experiment was performed for 48 hr, the concentration of Li+ ions contained in the leach liquor decreased from 1160 to 236 mg/L. To investigate the origin of this phenomenon, the obtained leach residue was analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. These analyses show that zeolite was formed around the lithium aluminum silicate glass-ceramics, which affected the leaching of by adsorbing Li+ ions. In addition, using the shrinking-core model and the Arrhenius equation, the leaching reaction with NaOH was found to depends on the chemical reaction of the two reactants, with a higher than 41.84 kJ/mol of the activation energy.

Introduction In some cases, the tongue and oesophagus tissues are damaged by the corrosive burn. Surgical interventions may cause scar formation, and severe burns treatment methods are limited. This study aims to investigate bromelain, a phytotherapeutic product, on the corrosive burn as a non-surgical option and as an adjunctive therapy, insofar as the treatment of corrosive wounds is not limited only to the treatment of oxidative stress and inflammatory reactions. Methods On the tongues of Wistar albino rats, chemically produced oral ulcers were created by topical application of NaOH (40%) solution, and in the distal oesophagus same mixture was applied to produce a corrosive oesophageal burn. For a week, they were treated orally by bromelain (100 mg/kg/day) or saline solution. At the end of seven days, animals were decapitated to remove the tongue and oesophagus, and blood samples were collected to obtain serum. Myeloperoxidase (MPO) activity, malondialdehyde (MDA), glutathione (GSH), interleukin-1 beta (IL-1β) and tumour necrosis factor-alpha (TNF-α) concentrations were measured in serum, and luminol and lucigenin chemiluminescence (CL) were measured in tissue samples. Results MDA and CL values were significantly increased, and GSH levels in tissue significantly decreased due to the corrosive burns. Saline treated corrosive burn group measured higher in the serum cytokines in according to the control group. Conclusions Bromelain administration decreased oxidant and inflammatory parameters and increased antioxidant levels in NaOH-induced corrosive burns. Thus, we concluded that bromelain may protect the tongue and oesophagus tissues with its anti-inflammatory and antioxidant effects.

This study successfully recycled alum sludge with either lithium slag or bottle glass to make high purity zeolite LTA beads. The basic synthesis approach was to fuse the waste material with sodium hydroxide then complete hydrothermal crystallization. Separate fusion of individual wastes promoted zeolite LTA formation compared to combined fusion. Preferred synthesis conditions were: 10 Na2O:Al2O3:2.5 SiO2:300 H2O; hydrothermal temperature = 80 °C; time = 5 h. Zeolite LTA purity was between 80 and 85 wt% from the two waste combinations. Use of pseudoboehmite and carboxymethyl cellulose favoured granulation/extrusion/spheronization of zeolite LTA powder. However, the beading process decreased calcium exchange capacity (CEC) from 99.5 to 37 mg Ca2+/g for alum sludge + lithium slag and from 64.5 to 37 mg Ca2+/g for alum sludge + waste glass. Additionally, when using 20 wt% pseudo-boehmite as a binder the ion-exchange equilibrium time increased from 60 to 300 min. The importance of not only making zeolite powder from waste materials but also to extend studies to shaped forms was evident. It is recommended that future studies should also focus on making extrudates or beads as these are the forms used commercially.

Chitosan (CS)/boron nitride nanoplatelet (BNNP) nanobiocomposite films were successfully prepared. Morphological results showed good dispersion of BNNPs in the CS matrix. After loading with BNNPs, water solubility (WS) and moisture absorption of the CS film decreased. The WS decreased from 41.2 to 27.8% at 7 wt% BNNP loading. Additionally, water vapor permeation decreased from 4.2 × 10−11 for pure CS film to 2.9 × 10−11 g m−1s−1Pa−1 at 7 wt% BNNP inclusion. The oxygen permeability of CS film decreased by up to 84% at 7 wt% BNNP loading. The composites showed better sodium hydroxide resistance compared with pure CS. Thermal stability of the composites was higher than the pure CS, up to 35 °C increase at 7 wt% BNNP loading. The addition of 5 wt% BNNPs improved Young's modulus by up to 45% compared with pure CS film. Cytotoxicity of the films decreased after loading with BNNPs.

The use of phosphonates as antiscalants in membrane processes is common. Before they are discharged into the receiving water, they should be removed from the membrane concentrate to protect the aquatic environment. This study conducted fixed-bed column experiments on the adsorption of diethylenetriaminepenta(methylene phosphonic acid) (DTPMP) and ortho-phosphate on granular ferric (hydr)oxide (GFH). The objective was to investigate the adsorption and desorption performance using real membrane concentrate, while testing both the usability of the GFH and that of the regeneration solutions over multiple cycles. Whereas a synthetic solution with DTPMP allowed almost complete regeneration, the adsorption performance with real membrane concentrate at the original pH ≅ 8 decreased significantly. This could be attributed to the precipitation of calcium compounds which disturbed the adsorption/desorption process. With the introduction of a novel acidic regeneration step to remove the precipitates, an adsorption performance of 95% over 20 cycles was achieved. The hydrochloric acid (HCl) can be reused when its pH is kept constant by a pH control. The sodium hydroxide solution (NaOH) for alkaline regeneration can be reused several times. However, the desorption performance decreased significantly when its electrical conductivity dropped below 90 mS/cm. Replacing the NaOH regularly can significantly improve the desorption performance.

In this study, a non-OPC binder as a cementless material for a road base stabilizer was established based on a hybrid material concept between the pozzolanic and the alkali-activated materials. Solid sodium hydroxide (NaOH) was used as an alkali additive in a dry mixing process to compensate for the early strength in a pozzolanic-based material matrix with its intrinsic property of delaying the strength gain. Effects of varied NaOH concentrations on the fly ash (FA) and hydrated lime (HL) mixes to generate such a non-OPC binder were investigated through the mechanical properties and microstructure observations. The selected non-OPC binders were then mixed with the road base aggregate to evaluate non-OPC-based mixtures' properties against the road base material specifications. The results revealed that the non-OPC binder, the FA–HL mix (FA:HL = 90:10 by weight) with the NaOH content of 3.5% wt by dry aggregate mass, provided the most effective mechanical properties an entire network of gel and needles-sharp cementitious products. Based on the pavement design conducted in this study, the flexible pavement with the non-OPC base layer provided a significantly lower cost and GHG emission than those of the OPC-based material as a benchmark. This non-OPC binder with a hybrid material concept reveals a great potential to be a cleaner product in road construction and rehabilitation for a new era of our low-carbon society.

To investigate the influence of chemical degradation on the mechanical (failure) behaviour of whey protein gels (WPGs), tensile and tensile relaxation experiments were performed on untreated and chemically treated gels. From each treatment performed, the tensile stresses increase with the applied strain rates, varying from 0.5%/s to 2.0%/s, indicating the time-dependent mechanical property of WPGs. Using sodium hydroxide solution with a concentration of 0.5 wt% showed a clear chemical degradation effect at higher immersion time, resulting in reduced tensile strength due to softer mechanical response and increased stress relaxation, making the WPG more flowable. Comparing the failure behaviour between untreated and 3.0 min treated WPG, the untreated gels show a brittle failure behaviour and exhibit a lower failure strain than the adequately treated ones. The measured failure strain can be used to predict the cohesive failure of WPG subject to the same chemical degradation. The stress–strain relationships, responding to different experimental conditions, provide useful input data for modelling the mechanical behaviour of WPG associated with the chemical damage of the protein network.

Hydrogen is a sustainable, renewable and clean energy carrier that meets the increasing energy demand. Pure hydrogen is produced by the hydrolysis of sodium borohydride (NaBH4) using a catalyst. In this study, Ni/TiO2 catalysts were synthesized by the sol-gel technique and characterized by X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) methods. The effects of Ni loading ratio (20–40%), catalyst amount (75–200 mg), the concentration of sodium hydroxide (NaOH, 0.25–1 M), initial amount of NaBH4 (75–125 mg) and the reaction temperature (20–60 °C) on hydrogen production performance were examined. The hydrogen yield (100%) and hydrogen production rate (110.87 mL/gcat.min) were determined at the reaction conditions of 5 mL of 0.25 M NaOH, 100 mg NaBH4, 100 mg Ni/TiO2, 60 °C. Reaction order and activation energy were calculated as 0.08 and 25.11 kJ/mol, respectively.

Synthetic fiber is more durable than most natural fibers, yet it has non-biodegradable characteristics. Biodegradable fibers such as green composites emerge as a potential substitution for non-biodegradable synthetic fibers since they are more eco-friendly and available. The natural fibers are the engineering outcomes resulting in lightweight products and good mechanical properties. They raise challenges in reinforcing green fibers as composite structures on a massive scale. This study introduces Timoho Fiber (TF) as reinforcement in preparing green composite. TF was treated with varied sodium hydroxide (NaOH) concentrations with equal immersion times. There was color alteration after TF was treated with NaOH; the TF color became brighter. The thermal resistance value was inversely proportional to the thickness value after the alkaline treatment. TF density and thermal endurance increased while TF thickness decreased along with the increase in NaOH concentration. The best crystallinity index and cellulose content were obtained with 9% NaOH. Likewise, untreated TF's tensile strength experienced a significant increase (555.26%) with 9% of alkaline treatment. The FTIR (Fourier-transform Infrared Spectroscopy) test result confirmed that alkaline treatment removed hemicellulose content, impurities, and excessive water absorption. Treated TF's surface became rougher. The etched surface indicated an interlocking with the matrix as displayed in SEM images. The positive treatment effects of NaOH on the TF show the TF's potential as green composites reinforcement to reduce the use of synthetic fibers.

The aim of present study is to investigate the modification of poor kaolin by boehmite to produce zeolite A via fusion techniques. The processed kaolins containing considerable content of quartz, as a major impurity, were employed, and alkalinity, boehmite content, fusion temperature, and ageing time were changed to achieve zeolite A. Regardless of the starting material composition, the sodium hydroxide/kaolin ratio should be fixed in the range of 2.00–2.33 to delete quartz. Boehmite was added to material mixtures for compensating aluminum deficit followed by thermal treatment at 700, and 800 °C. The presence of boehmite in the precursors is very crucial for the formation of zeolite A. The maximum relative crystallinity was obtained by control of the boehmite/kaolin ratio at the level of 0.26. The zeolite A produced from clay containing illite + kaolinite + pyrophyllite indicated the semi-cubic particles with rounded edges, and lower surface area, 17.5 m2.g−1 while the application of kaolinite-rich clay resulted in the mesoporous product with an average pore size of 8 nm, and larger surface area of about 59.6 m2.g−1.