Hydrochloric Research Articles

Effect of Temperature on Zirconia Powder Synthesized from Amang Zirconium Oxychloride Precursor

Silica (SiO2) is widely used in numerous applications, including ceramic membranes, and can be extracted from rice husks, which is an agricultural waste containing high amounts of silica. In fact, it is essential to reduce the vast amounts of discarded rice husks as open burning of the rice husk can have detrimental effects on the environment due to the release of hazardous pollutants. For the rice husk to be used, a suitable sintering temperature should be obtained to ensure the membrane synthesized has the desired porous structure. A high sintering temperature can affect the melting condition of the membrane’s porous structure. While a low sintering temperature may not give the required porosity. Therefore, this study aims to evaluate the effect of sintering temperature on the pore size of the membrane fabricated from kaolin, polyvinyl alcohol, and rice husk ash. The rice husk was initially treated with hydrochloric acid (HCl) and heated at 900 ℃ to produce rice husk ash. The membranes fabricated were then sintered at 1000 ℃ to 1400 ℃. X-ray fluorescence (XRF) results show that 71.36% of silica was successfully extracted from the rice husk. According to the XRD results, only two membranes sintered at 1300 °C and 1400 °C have crystallinity forms. Because the ceramic membrane contains a crystalline phase, it was determined that 1300 °C is an appropriate temperature for sintering. It also has a low absorption percentage (88.89%) and the desired porosity (69.93%).

Evaluation of an Extraction Chromatographic Resin Based on the DOODA Extractant: Characterization, Comparison to DGA, and Potential Applications

ABSTRACT The extraction of selected metal ions by an extraction chromatographic (EXC) resin containing N,N,N’,N’-tetraoctyl-3,6-dioxaoctane diamide (DOODA) on a porous methacrylate support was measured from nitric acid and hydrochloric acid. Metal ion extraction with the DOODA resin was compared to structurally similar diglycolamide (DGA) resins containing the extractants N,N,N’,N’-tetraoctyl-diglycolamide (TODGA; DGA, Normal resin) and N,N,N’,N’-tetra(2-ethyl-1-hexyl)-diglycolamide (TEHDGA; DGA, Branched resin). The EXC resins were studied via batch uptake, column elution, extraction capacity, and column stability experiments focusing on potential applications in analytical radiochemistry and nuclear medicine isotope production and purification. The DOODA resin exhibited similar extraction trends to the DGA resins for many metal ions, however, the capacity factors (k’) were reduced, typically following the trend of DGA, normal > DGA, branched > DOODA. The selectivity of DOODA resin towards rare earth elements, trivalent actinides, and some transition metal ions, particularly Cd, Ca, and Ac, is quite different from the existing DGA resins, but follows trends previously identified in solvent extraction experiments. The capacity for extraction of Ca(II) and Eu(III) from nitric acid was higher for the DOODA resin than either DGA resin, while all resins exhibited little extractant loss to the mobile phase over >18,000 bed volumes of elution.

Surface characteristics of maraging steel during electropolishing as a function of polishing time

ABSTRACT Thermal-based machining process like EDM, Laser-assisted additive manufacturing process degrades the surface integrity of the component. Therefore, a post-polishing method is required to improve the surface integrity as well as the performance of the component. A gyroscope, made of maraging steel, fabricated by EDM, is utilised in space industry and has poor surface integrity, which affects its performance. Thus, electropolishing (EP), a non-conventional polishing process, is used for the above said problem as it possesses several advantages over other polishing methods. There are very few literatures available for EP of maraging steel. The present manuscript is the preliminary analysis for the electrolyte (Ortho-phosphoric acid, sulphuric acid and hydrochloric acid) and its effect on maraging steel with respect to time. The surface characteristics such as surface roughness and surface reflectivity, along with surface elemental composition, have been evaluated. With increase in time, maximum improvement in surface roughness and surface reflectivity is 61.23% and 70%, respectively. It can be concluded that the selected electrolyte gives a promising improvement in the surface characteristics of maraging steel.

Structure Remodeling Strategy for Open-Cage NiFe@Fe-bis-PBA with Enhanced Peroxidase-like Activity To Monitor Tumor Markers.

The inherent metal elements and structures of Prussian blue analogue (PBA) nanozymes have restricted their enzyme-mimicking activity. Therefore, the rational regulation of PBA nanozymes to improve their catalytic activity is highly desirable for biosensing applications. Herein, we propose a structure remodeling strategy to construct an open-cage Fe PBA-anchored NiFePBA (NiFe@Fe bis-PBA) nanozyme with significantly enhanced enzyme-mimicking activity. The formation process and mechanism for this bis-PBA nanozyme were studied in detail. Specifically, a cubic NiFePBA precursor was first synthesized and modified with polyvinylpyrrolidone (PVP). With the aid of hydrochloric acid, the added potassium ferricyanide was reduced by PVP and re-coordinated on the surface of NiFePBA to form the NiFe@Fe bis-PBA nanozyme with a special open-cage core-shell structure. The resultant NiFe@Fe bis-PBA nanozyme was further exploited to immobilize secondary antibodies, serving as a novel signal probe for developing highly sensitive electrochemical immunosensors for monitoring tumor markers. The constructed electrochemical immunosensor possesses a very wide linear range of 0.005-100 ng/mL and a low detection limit of 0.89 pg/mL for alpha-fetoprotein with high specificity and acceptable reproducibility and stability. This work offers a general and promising strategy for remodeling PBA nanozymes with a very favorable structure and metal element distribution, which enhances their enzyme-mimicking properties for applications in different fields.

Turning coal hydrogenation liquefaction residue into high conductivity carbon black with magnesium citrate-assisted steam activation followed by high temperature treatment

The high conductivity carbon black was prepared using coal hydrogenation liquefaction residue as raw material, through a combination methods of solvent extraction purification, magnesium citrate-assisted carbonization, steam activation, and high-temperature treatment. The effects of carbonization and activation process parameters, heat treatment temperatures, and other factors on the microstructure, specific surface area, degree of graphitization, and conductivity of the carbon black were studied. The coal direct liquefaction residue was firstly purified using a xylene and tetrahydrofuran solution with a volume ratio of 1:1 by centrifugal separation method to obtain coal liquefaction asphalt. Then, the coal liquefaction asphalt was mixed with magnesium citrate in a mass ratio of 3:7 and ball-milled for 90 min. After carbonizing at 950 °C for 120 min, magnesium ions were leached out with hydrochloric acid. The obtained sample was activated with steam at 900 °C for 100 min and then underwent high-temperature treatment at 1500 °C under a N2 atmosphere for 120 min. The microstructure of the conductive carbon black exhibited an irregular blocky structure with an average particle size of 2–10 μm. The specific surface area of carbon material was 579.69 m2/g, with the pore distribution predominantly microporous, accounting for 69.81 % of the total pore volume. It featured a higher degree of graphitization (ID/IG=1.06) and fewer surface oxygen-containing functional groups compared with coal direct liquefaction residue. Electrochemical testing showed that the electrical resistance of the carbon material was only 1.55 Ω, and the reversible capacity under a current density of 1 A/g was 96 mAh/g, which are superior to those of the existing commercial conductive carbon black. The microporous structure and higher degree of graphitization facilitate efficient electron transmission, while the lower content of surface oxygen functional groups effectively reduces electron transfer resistance. This work offers new insights into the structural design and performance enhancement of coal liquefaction residue-derived conductive carbon black functional materials. Furthermore, it has significant implications for the future development of conductive carbon black in energy saving and energy storage.

Noninvasive biomarkers for the detection of GERD-induced pulmonary injury.

The role of gastroesophageal reflux in progressive lung damage is increasingly recognized. We have proposed, based on our work with lung transplant recipients, a novel immune mechanism of pulmonary injury after aspiration of gastric contents, during which higher levels of normally sequestered lung self-antigens (SAgs) collagen V (Col-V) and K-alpha-1 tubulin (Kα1T) in circulating small extracellular vesicles (EVs) induce the production of self-antibodies (SAbs) anti-Col-V and anti-Kα1T. Thus, we aimed to determine whether levels of SAbs or SAgs increased in an animal model of aspiration-induced lung damage in a nontransplant setting. We created a murine model of repetitive lung aspiration using C57BL/6J mice. Mice were aspirated weekly with 1mL/kg of hydrochloric acid (n = 9), human gastric contents (n = 9), or combined (1:1) fluid (n = 9) once, three, or six times (n = 3 in each subgroup; control group, n = 9). Blood samples were periodically obtained, and all animals were sacrificed at day 90 for pathological assessment. SAbs were measured using an enzyme-linked immunosorbent assay; SAgs and NF-κB contained in small EVs were assessed by western blot. Aspirated mice weighed significantly less than controls throughout the study and had histological evidence of pulmonary injury at day 90. Overall, aspirated mice developed higher concentrations of anti-Col-V at day 28 (53.9 ± 28.7 vs. 29.9 ± 4.5ng/mL, p < 0.01), day 35 (42.6 ± 19.8 vs. 28.6 ± 7.2ng/mL, p = 0.038), and day 90 (59.7 ± 27.7 vs. 34.1 ± 3.2ng/mL, p = 0.014) than the control group. Circulating small EVs isolated from aspirated mice on day 90 contained higher levels of Col-V (0.7 ± 0.56 vs. 0.18 ± 0.6m.o.d., p = 0.009) and NF-κB (0.42 ± 0.27 vs. 0.27 ± 0.09m.o.d., p = 0.095) than those from controls. This experimental study supports the theory that gastroesophageal reflux leads to the development of lung damage and an increase of humoral markers that may serve as noninvasive biomarkers to detect asymptomatic lung injury among patients with gastroesophageal reflux disease.

Analyte-dependent Rabi splitting in solid-state plexcitonic sensors based on plasmonic nanoislands strongly coupled to J-aggregates

A key challenge in the field of plexcitonic quantum devices is the fabrication of solid-state, device-friendly plexcitonic nanostructures using inexpensive and scalable techniques. Lithography-free, bottom-up nanofabrication methods have remained relatively unexplored within the context of plexcitonic coupling. In this work, a plexcitonic system consisting of thermally dewetted plasmonic gold nanoislands (AuNI) coated with a thin film of J-aggregates was investigated. Control over nanoisland size and morphology allowed for a range of plasmon resonances with variable detuning from the exciton. The extinction spectra of the hybrid AuNI/J-aggregate films display clear splitting into upper and lower hybrid resonances, while the dispersion curve shows anti-crossing behavior with an estimated Rabi splitting of 180 eV at zero detuning. As a proof of concept for quantum sensing, the AuNI/J-aggregate hybrid was demonstrated to behave as a plexcitonic sensor for hydrochloric acid vapor analyte. This work highlights the possibility of using thermally dewetted nanoparticles as a platform for high-quality, tunable, cost-effective, and scalable plexcitonic nanostructures for sensing devices and beyond.

Carbonyl Iron Particles’ Enhanced Coating Effect Improves Magnetorheological Fluid’s Dispersion Stability

The coating effect of 1,2-bis(triethoxysilyl)ethane (BTES) on carbonyl iron particles (CIPs) was enhanced by etching with hydrochloric acid (HCl) of various concentrations, and magnetorheological fluids (MRFs) with significantly improved dispersion stability were obtained. The microstructures, coating effect, and magnetism of CIPs were examined using scanning electron microscopy (SEM), automatic surface and porosity analysis (BTE), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and a vibrating sample magnetometer (VSM), respectively. Furthermore, the rheological properties and dispersion stability of the MRFs were assessed by a rotating rheometer and a Turbiscan Tower. The results show that as the HCl concentration increased, nanopores appeared on CIPs and then disappeared, and the specific surface area of the particles increased and then decreased. When the concentration of HCl was 0.50 mol/L, the number of nanopores and the specific surface area of particles changed sharply. Not only that, the coated mass of BTES increased greatly and the saturation magnetization of particles decreased sharply. As the coated mass increased, without a magnetic field, the viscosity and shear stress of the MRFs increased, especially when the coated mass was more than 2.45 wt.%; while under a magnetic field, the viscosity and shear stress decreased, and the sedimentation rate of the MRFs decreased from 0.13 to 0.01 mm/h. By controlling the concentration of HCl for etching, the coating effect of CIPs was greatly enhanced, and thus an MRF with superior shear stress and excellent dispersion stability was obtained, which is significant in basic research and MRF-related applications.

Optimal extraction, phytochemical and electrochemical potential assessment of pigments from Persicaria Lapathifolia for dye-sensitized solar cell application

In this study, we concentrated on optimal extraction, phytochemical, and electrochemical assessment of natural pigments from the roots and flowers of Persicaria lapathifolia as new sensitizers in dye-sensitized solar cells. The extraction technique required optimizing the use of acidified ethanol with acetic acid and hydrochloric acid as flower and root extractants, respectively. Photo-electrochemical tests revealed that these pigments could improve the efficiency of DSSCS. The optical characterization revealed maximal absorbance peaks at 462 and 654 nm for root dye and 535, 606 and 666 nm for blossom dye. Phytochemical examination revealed the presence of anthocyanins flavonoids glycoside linkage and betacyanin in both extracts. The Cyclic voltammetry tests revealed oxidation potential peaks in root and floral dyes the HOMO and LUMO potentials were calculated for both dyes, revealing values that could help improve DSSC performance. The DSSCS sensitized with flower extract had an open circuit voltage of 0.649 V a brief current pulse of 3.8 mA and an efficiency of 1.6335%. On the other hand root, pigment-based DSSCS performed slightly inferior with a Voc of 0.55 V an Isc of 3.7 mA, and an efficiency of 1.33%. These findings point to the potential of Persicaria lapathifolia pigments to boost DSSC efficiency emphasizing the relevance of sustainable energy sources. More research and optimization are required to realize the potential of these natural pigments for DSSC applications. This study adds to the investigation of green energy options, notably rooftop photovoltaic systems, in response to an increasing desire for ecologically sound energy solutions.

Evaluation of probiotic efficacy of indigenous yeast strain, Saccharomyces cerevisiae Y-89 isolated from a traditional fermented beverage of West Bengal, India having protective effect against DSS-induced colitis in experimental mice.

Increasing awareness regarding health promotion and disease prevention has driven inclusion of fermented foods and beverages in the daily diet. These are the enormous sources of beneficial microbes, probiotics. This study aims to isolate yeast strains having probiotic potential and effectivity against colitis. Initially, ninety-two yeast strains were isolated from Haria, an ethnic fermented beverage of West Bengal, India. Primary screening was done by their acid (pH 4) and bile salt (0.3%) tolerance ability. Four potent isolates were selected and found effective against Entamoeba histolytica, as this human pathogen is responsible to cause colitis. They were identified as Saccharomyces cerevisiae. They showed luxurious growth even at 37 oC, tolerance up to 5% of NaCl, resistance to gastric juice and high bile salt (2.0%) and oro-gastrointestinal transit tolerance. They exhibited good auto-aggregation and co-aggregation ability and strong hydrophobicity. Finally, heat map and principal component analysis revealed that strain Y-89 was the best candidate. It was further characterised and found to have significant protective effects against DSS-induced colitis in experimental mice model. It includes improvement in colon length, body weight and organ indices; reduction in disease activity index; reduction in cholesterol, LDL, SGPT, SGOT, urea and creatinine levels; improvement in HDL, ALP, total protein and albumin levels; decrease in coliform count and restoration of tissue damage. This study demonstrates that the S. cerevisiae strain Y-89 possesses remarkable probiotic traits and can be used as a potential bio-therapeutic candidate for the prevention of colitis.

Boosting Zinc‐Ion Storage Capability in Longitudinally Aligned MXene Arrays with Microchannel Architecture

AbstractFlexible Zn2+ ion hybrid capacitors (ZHCs) will play a crucial role in developing next‐generation wearable products, which demand portability, durability, and environmental adaptability. To further meet these requirements, Ti3C2Tx MXene with exceptional conductivity and robust mechanical properties can be utilized as cathodes, except for challenges such as the dense stacking of Ti3C2Tx nanosheets. In this study, a novel MXene cathode architecture has been developed with the facilitation of an ice template, which creates longitudinally aligned Ti3C2Tx arrays with microchannels. The introduction of hydrochloric acid to the Ti3C2Tx slurry induces a crumpled morphology, increasing active sites and enhancing ion transport with expanded interlayer spacing. Interestingly, experimental results and COMSOL simulations verify that the cathode structure also has effective impacts on the Zn anode with a weakened ion concentration gradient and suppressed dendrite formation. Consequently, the ZHCs exhibit enhanced electrochemical performance with excellent rate performance and long‐term cycling stability (enduring over 50 000 cycles at 5 A g−1) and further deliver a reliable low‐temperature operation by applying an anti‐freezing electrolyte. Moreover, flexible ZHCs assembled with gel electrolytes demonstrate excellent flexibility, improved rate performance, and mechanical stability, making them well‐suited for flexible electronics that power flexible LED panels.

OBTAINING COAGULANT FROM AUMINZATAU KAOLIN FOR PPM WASTEWATER PURIFICATION

This article is devoted to the development of methods for obtaining raw materials and coagulants based on Auminzatau kaolin at the Zarkuduk site and the treatment of highly coloured wastewater from the production of paper from rice and wheat straw. The yield of kaolin, treated with a 30 % hydrochloric acid solution at an optimum calcination temperature of 500°C for 90 min, was 97.5 %. The optimum temperature for the interaction of hydrochloric acid is 25 - 30°C for 30 - 45 min. The efficiency of the coagulant application is 97.5 %.

The Initiation Mechanism of the Isoolefin Oligomerization Reaction in the Presence of Ethylaluminum Dichloride – Protonodonor Complex Catalysts

The mechanism of isoolefins initiation in the presence of ethylaluminum dichloride – proton donor (water, phenol, hydrochloric acid) complex catalysts has been studied by ab initio HF.3.21G. The energetics of these reactions was estimated, the values of its activation energy and thermal effects were obtained. It was found that among the studied catalysts, an increase in the activation energy of the reaction of initiation of oligomerization of isoolefins contributes to an increase in the selectivity of the process.

Reactive capture of CO2 via amino acid

Reactive capture of carbon dioxide (CO2) offers an electrified pathway to produce renewable carbon monoxide (CO), which can then be upgraded into long-chain hydrocarbons and fuels. Previous reactive capture systems relied on hydroxide- or amine-based capture solutions. However, selectivity for CO remains low (<50%) for hydroxide-based systems and conventional amines are prone to oxygen (O2) degradation. Here, we develop a reactive capture strategy using potassium glycinate (K-GLY), an amino acid salt (AAS) capture solution applicable to O2-rich CO2-lean conditions. By employing a single-atom catalyst, engineering the capture solution, and elevating the operating temperature and pressure, we increase the availability of dissolved in-situ CO2 and achieve CO production with 64% Faradaic efficiency (FE) at 50 mA cm−2. We report a measured CO energy efficiency (EE) of 31% and an energy intensity of 40 GJ tCO−1, exceeding the best hydroxide- and amine-based reactive capture reports. The feasibility of the full reactive capture process is demonstrated with both simulated flue gas and direct air input.

Exploring the molarity of Lithium Fluoride in minimally intensive layer delamination (MILD) method for efficient room temperature synthesis of high quality Ti3C2Tx free-standing film

In recent years, MXene has become the most demanding material in the 2D family, leading to their increased use in research for a diverse range of applications, such as energy storage, water purification, optoelectronics, electromagnetic interference (EMI) shielding and medicine. However, recent research has made it increasingly important to synthesize high-quality MXene in a safe, reliable, fast, reproducible, and good-yielding single-step method. To achieve high-quality MXene by etching the MAX phase precursors, it is very important to critically optimize synthesis parameters, such as etching method, etchant concentrations, temperature, time, etc. Minimally intensive layer delamination (MILD) method for MXene synthesis using Lithium Fluoride (LiF) salt and hydrochloric (HCl) acid seems to be a better choice in the context of improved performance in different applications as well as its scalability and reproducibility. Here, the molar ratio of HCL/LIF is critical for Aluminium etching at room temperature to produce a high-quality MXene with = O, -OH, -F termination groups in the MILD method. However, in case of MILD method the effect of LiF/HCL concentrations on quality of MXene need to be addressed. In this study, we focus on room temperature etching of Ti3AlC2 using MILD method to synthesize quasi two-dimensional carbide (Ti3C2) MXene. The influence of molarity concentration of etchants (LiF and HCl) on quality of MXene has been thoroughly investigated. Different molar concentrations of Lithium Fluoride (LiF) with fixed HCL concentration were tested at room temperature for 24 h in the etching process. The crystal structure, microstructure and composition of the MXene were characterized using X-ray diffraction, Raman spectroscopy, and electron microscopy. Flexible free-standing MXene film with largest shift in the characteristic (002) peak, indicating large interplanar spacing, has been successfully achieved repeatedly for an optimum molar concentration of etchants at room temperature.

Microwave digestion method for sulfide analysis of Çanakkale region coal

ABSTRACT Quantitative analysis of sulfide content in coal is a necessary step for complete analysis. Conventional analysis methods take several days, whereas it takes a few hours in microwave digestion method. In the present study, a new wet chemical analysis technique was developed and applied to quantify the sulfide content in Turkish coal samples. In the initial step, 5 M HCl solution is employed to dissolve the sulfate phases present in the coal. Subsequently, pyrite is separated from the residue obtained in stage 1 through the utilization of 2 M HNO3 solution. The final stage involves the determination of organic sulfur, wherein concentrated HNO3, HCl, HF, and boric acid are utilized to completely decompose the remaining residue from stage 2. The extracted solutions from each stage are promptly analyzed for sulfur content using ICP-OES. The cumulative values of the three sulfur forms consistently correspond with certified total sulfur data for the majority of the examined coals. Among several advantages, the analysis duration is the most distinctive feature. Chemical analysis of sulfide in coal with microwave analysis method completed three times rapid than with conventional analysis.

Corrosion behaviour of 110SS steel in hydrochloric acid and blended acid system at 200°C

The influence of organic acids (formic acid, acetic acid) on the corrosion behaviour of 110SS steel, a hydrogen sulphide corrosion resistant alloy steel, in hydrochloric (HCl) acid environments was studied. The corrosion rates of 110SS steels in HCl acid and blended acid were measured using the high-temperature and high-pressure corrosion tester. Scanning electron microscopy was utilised to observe the morphology of corrosion products on steel samples corroded by different acid systems, and the energy dispersive X-ray spectrometer was used to analyse the elemental composition of the corrosion products. The corrosion morphology was observed using a 3D laser scanner. The results indicated that the corrosion rate of 110SS steel in HCl acid at 200 °C was an exponential function of HCl concentration. Reducing the HCl concentration significantly decreased the corrosion rate of 110SS steel. Organic acids and corrosion inhibitors synergistically reduced the corrosion of 110SS steel in HCl acid. Adding 3 wt.% organic acid to the 15 wt.% HCl acid system further reduced the corrosion rate, with a more pronounced effect observed in the HCl–formic acid system compared to the HCl–acetic acid system. Organic acids chemically adsorbed onto the steel surface and decomposed to produce CO, which hindered the attack of hydrogen ions on the metal. The added corrosion inhibitor and intensifier Sb2O3 resulted in the formation of a compact adsorption film on the steel surface, further inhibiting corrosion. The optimal mass ratio of HCl acid to organic acid was found to be 15% to 3%.

Lycium barbarum extract as an environmentally friendly corrosion inhibitor for AISI 52100 bearing steel in hydrochloric acid medium

This study reports the use of Lycium barbarum extract (LBE), a green and environmentally friendly additive, to inhibit the corrosion of AISI 52100 bearing steel in 1 M hydrochloric acid (HCl) solutions. Corrosion inhibition was experimentally investigated via the weight loss method and electrochemical analyses. The surface morphologies were evaluated by scanning electron microscopy (SEM), and the chemical compositions were analyzed via energy-dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR). The experimental electrochemical and weight loss results demonstrated that LBE has excellent inhibitory properties, with the highest inhibition efficiencies of 92.68 % and 92.31 % when the concentration is 500 ppm, for steel immersed in HCl solutions. Surface coverage studies revealed that the data for the adsorption of LBE on steel were consistent with the Langmuir isotherm. The initial process was investigated via polarization analysis, and the LBE adsorption process was found to be a hybrid of physical and chemical adsorption. To investigate the effectiveness of LBE in preventing corrosion, the corrosion inhibition mechanism was analyzed via a wettability study, high performance liquid chromatography (HPLC) measurements and theoretical quantum chemical calculations. The results indicated that Ara, Rha, Man and Glu played significant effect on the protection of bearing steel in 1 M HCl solution.

“Treating Waste with Waste”: Utilizing Phosphogypsum to Synthesize Porous Calcium Silicate Hydrate for Recovering of Fe2+ from Pickling Wastewater

Phosphogypsum is a by-product of the wet-process phosphoric acid production, and it is rich in Ca and S. Long-term storage of Phosphogypsum can cause serious pollution to the environment; therefore, promoting the sustainable utilization of Phosphogypsum is crucial. This study proposes the use of Phosphogypsum and silicic acid in a sodium hydroxide solution for the hydrothermal synthesis of porous calcium silicate hydrate adsorbent, which is used for adsorbing Fe2+ from simulated hydrochloric acid pickling wastewater. Under the optimal synthesis conditions (37.5 g/L of NaOH, calcium/silicon ratio of 1.0, liquid/solid ratio of 15:1 mL/g, 110 °C, and 4 h), the conversion rate of SO42− in Phosphogypsum is 87.41%. Porous calcium silicate hydrate exhibits excellent OH− release capability in Fe2+-containing pickling wastewater. The adsorption process for Fe2+; is mainly chemical adsorption, involving ion exchange between Ca2+ and Fe2+, as well as complexation reactions of O-Si-O group, -OH group, and Si-O group with Fe2+. This technology aims to provide a solution for the sustainable utilization of Phosphogypsum and the recovery of Fe2+ from pickling wastewater, which has significant practical importance.

Development of a Superhydrophobic Protection Mechanism and Coating Materials for Cement Concrete Surfaces.

In order to further enhance the erosion resistance of cement concrete pavement materials, this study constructed an apparent rough hydrophobic structure layer by spraying a micro-nano substrate coating on the surface layer of the cement concrete pavement. This was followed by a secondary spray of a hydroxy-silicone oil-modified epoxy resin and a low surface energy-modified substance paste, which combine to form a superhydrophobic coating. The hydrophobic mechanism of the coating was then analysed. Firstly, the effects of different types and ratios of micro-nano substrates on the apparent morphology and hydrophobic performance of the rough structure layer were explored through contact angle testing and scanning electron microscopy (SEM). Subsequently, Fourier transform infrared spectroscopy and permeation gel chromatography were employed to ascertain the optimal modification ratio, temperature, and reaction mechanism of hydroxy-silicone oil with E51 type epoxy resin. Additionally, the mechanical properties of the modified epoxy resin-low surface energy-modified substance paste were evaluated through tensile tests. Finally, the erosion resistance of the superhydrophobic coating was tested under a range of conditions, including acidic, alkaline, de-icer, UV ageing, freeze-thaw cycles and wet wheel wear. The results demonstrate that relying solely on the rough structure of the concrete surface makes it challenging to achieve superhydrophobic performance. A rough structure layer constructed with diamond micropowder and hydrophobic nano-silica is less prone to cracking and can form more "air chamber" structures on the surface, with better wear resistance and hydrophobic performance. The ring-opening reaction products that occur during the preparation of modified epoxy resin will severely affect its mechanical strength after curing. Controlling the reaction temperature and reactant ratio can effectively push the modification reaction of epoxy resin through dehydration condensation, which produces more grafted polymer. It is noteworthy that the grafted polymer content is positively correlated with the hydrophobicity of the modified epoxy resin. The superhydrophobic coating exhibited enhanced erosion resistance (based on hydrochloric acid), UV ageing resistance, abrasion resistance, and freeze-thaw damage resistance to de-icers by 19.41%, 18.36%, 43.17% and 87.47%, respectively, in comparison to the conventional silane-based surface treatment.