Alkaline Hydrothermal Treatment Research Articles

Experimental and Theoretical Insight of Perfluorooctanoic Acid Destruction by Alkaline Hydrothermal Treatment Enhanced with Zero-Valent Iron in Biochar

Experimental and Theoretical Insight of Perfluorooctanoic Acid Destruction by Alkaline Hydrothermal Treatment Enhanced with Zero-Valent Iron in Biochar

Co3O4/hydrogen titanate composite nanomaterials with enhanced enzyme-like activity for antibacterial application

Co3O4/hydrogen titanate (HTO) nanocomposites were prepared though a facile dissolution-reprecipitation method and post alkaline hydrothermal treatment. Compared with pure Co3O4, as-designed Co3O4/HTO catalyst with optimum Ti/Co ratio showed highly enhanced peroxidase-like activity that can catalyze H2O2 to produce more reactive oxygen species. The enhanced enzyme-like catalytic performance was contributed to the HTO sheets that prevent the agglomeration of Co3O4 nanoparticles during the preparation, and thus expose more catalytic active sites. As a result, the bacteriostatic efficiencies of the catalyst against E. coli with the presence of 1 mM H2O2 is about 2 times higher than that without H2O2 addition, exhibiting an excellent bacteriostatic activity.

Synthesis, Characterization of NaA Zeolite from Blast Furnace Slag (BFS) via Alkaline Fusion and Hydrothermal Treatment

Synthesis, Characterization of NaA Zeolite from Blast Furnace Slag (BFS) via Alkaline Fusion and Hydrothermal Treatment

Novel Strategy for Surface Modification of Titanium Implants towards the Improvement of Osseointegration Property and Antibiotic Local Delivery

The topography and chemical composition modification of titanium (Ti) implants play a decisive role in improving biocompatibility and bioactivity, accelerating osseointegration, and, thus, determining clinical success. In spite of the development of surface modification strategies, bacterial contamination is a common cause of failure. The use of systemic antibiotic therapy does not guarantee action at the contaminated site. In this work, we proposed a surface treatment for Ti implants that aim to improve their osseointegration and reduce bacterial colonization in surgery sites due to the local release of antibiotic. The Ti discs were hydrothermally treated with 3M NaOH solution to form a nanostructured layer of titanate on the Ti surface. Metronidazole was impregnated on these nanostructured surfaces to enable its local release. The samples were coated with poly(vinyl alcohol)-PVA films with different thickness to evaluate a possible control of drug release. Gamma irradiation was used to crosslink the polymer chains to achieve hydrogel layer formation and to sterilize the samples. The samples were characterized by XRD, SEM, FTIR, contact angle measurements, "in vitro" bioactivity, and drug release analysis. The alkaline hydrothermal treatment successfully produced intertwined, web-like nanostructures on the Ti surface, providing wettability and bioactivity to the Ti samples (Ti + TTNT samples). Metronidazole was successfully loaded and released from the Ti + TTNT samples coated or not with PVA. Although the polymeric film acted as a physical barrier to drug delivery, all groups reached the minimum inhibitory concentration for anaerobic bacteria. Thus, the surface modification method presented is a potential approach to improve the osseointegration of Ti implants and to associate local drug delivery with dental implants, preventing early infections and bone failure.

KOH-Based Hydrothermal Synthesis of Iron-Rich Titanate Nanosheets Assembled into 3D Hierarchical Architectures from Natural Ilmenite Mineral Sands

The synthesis of titanate nanostructures from low-cost mineral precursors is a topic of continuous interest, considering not only their fundamental aspects but also the benefits of incorporating such nanomaterials in a wide variety of applications. In this work, iron-rich titanate nanosheets were synthesized from Ecuadorian ilmenite sands (ilmenite–hematite solid solution-IHSS) through an alkaline hydrothermal treatment (AHT) using potassium hydroxide (KOH). The effect of the duration of the KOH-AHT was assessed at 180 °C for 24, 48, 72, and 96 h. The morphology evolution over time and the plausible formation mechanisms of titanate nanostructures were discussed. The most significant morphological transformation was observed after 72 h. At this time interval, the titanate nanostructures were assembled into well-defined 3D hierarchical architectures such as book-block-like arrangements with open channels. Based on X-ray powder diffraction (XRPD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) analyses, it was determined that these nanostructures correspond to iron-rich layered titanates (Fe/Ti mass ratio of 7.1). Moreover, it was evidenced that the conversion of the precursor into layered nanostructures was not complete, since for all the tested reaction times the presence of remaining IHSS was identified. Our experiments demonstrated that the Ecuadorian ilmenite sands are relatively stable in KOH medium.

Preparation and characterization of Ce-MOF/g-C3N4 composites and evaluation of their photocatalytic performance

In this study, unique hybrid structures were constructed between a Ce-based metal-organic framework (Ce-MOF) and graphitic carbon nitride (g-C3N4) materials. In addition, the g-C3N4 materials used for these heterostructures were prepared by five different methods, namely the conventional pyrolysis method, chemical exfoliation by a strong acid, activation by an alkaline hydrothermal treatment, melamine-cyanuric acid supramolecular assembly with a mechanochemical method, and by the solvothermally pre-treated method. The structural and morphological properties of the resulting g-C3N4 sheets and their composites were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), thermogravimetric analysis-derivative thermogravimetry (TGA-DTG), diffuse reflectance UV–vis spectroscopy (UV–vis DRS) and N2 sorption-desorption isotherms (BET). Finally, the photocatalytic performance of the composites was determined by following the photocatalytic degradation of methylene blue (MB) in an aqueous solution under UV–visible light irradiation. It was found that the photocatalytic efficiency of the Ce-MOF/g-C3N4‒TS composite was significantly higher than that of their counterparts (Ce-MOF or g-C3N4‒TS) for the photocatalytic degradation of MB. When employing the composite, UV light-induced degradation of MB yielded an efficiency of 96.5% after 120 min for a dye solution containing 10 mg/L MB. This corresponds to a 5-fold or 2-fold improvement of the rate constant (k) when compared to the Ce-MOF or g-C3N4, respectively.

Analysis of the Behavior of As and Pb during the Pretreatments Applied to a Jarosite Residue for the Recovery of Gold and Silver

The recovery of valuable metals from jarosites is a topic of great relevance regarding the implementation of the circular economy; however, these materials also contain metals such as arsenic and lead, which are harmful to health and the environment. Considering these factors, it is important to monitor these metals at each stage of treatment used to recover the valuable metals. In the present work, the behavior of As and Pb was assessed during the pretreatment conducted on a jarositic residue using direct zinc leaching (DLR), as well as leaching in cyanide and cyanide media with glycine. It was found that when no DLR pretreatment was performed, As and Pb naturally dissolved in the cyanide-leaching medium at concentrations of 34.08 mg/L and 99.12 mg/L, respectively. When an alkaline treatment was conducted on the residue (DLR-AH), it was found that there was no presence of As and Pb in the cyanidation solution, while in the case of the cyanide solution with glycine, we observed 83.35 mg/L of As and 213.63 mg/L of Pb. During the oxidizing alkaline hydrothermal treatment (DLR-AHO), 27.5 mg/L of As and 106.78 mg/L of Pb were detected in the cyanide solution. In the cyanide solution with glycine, there was less dissolution of As and Pb (11.68 and 66.75 mg/L), respectively. Finally, when desulfurization of the DLR was conducted prior to the DLR-AHO treatment, the dissolution of As and Pb increased due to the elemental sulfur covering the arsenopyrite and galena particles, so that, when removed, these were more susceptible to pretreatment and cyanidation.

Extraction of Novel Effective Nanocomposite Photocatalyst from Corn Stalk for Water Photo Splitting under Visible Light Radiation

Novel (Ca, Mg)CO3&SiO2 NPs-decorated multilayer graphene sheets could be successfully prepared from corn stalk pith using a simple alkaline hydrothermal treatment process followed by calcination in an inert atmosphere. The produced nanocomposite was characterized by SEM, EDX, TEM, FTIR, and XRD analytical techniques, which confirm the formation of multilayer graphene sheets decorated by inorganic nanoparticles. The nanocomposite shows efficient activity as a photocatalyst for water-splitting reactions under visible light. The influence of preparation parameter variations, including the alkaline solution concentration, hydrothermal temperature, reaction time, and calcination temperature, on the hydrogen evolution rate was investigated by preparing many samples at different conditions. The experimental work indicated that treatment of the corn stalk pith hydrothermally by 1.0 M KOH solution at 170 °C for 3 h and calcinating the obtained solid at 600 °C results in the maximum hydrogen production rate. A value of 43.35 mmol H2/gcat.min has been obtained associated with the energy-to-hydrogen conversion efficiency of 9%. Overall, this study opens a new avenue for extracting valuable nanocatalysts from biomass wastes to be exploited in hot applications such as hydrogen generation from water photo-splitting under visible light radiation.

Endowing osseointegration ability to bioinert alumina by carbonate apatite coating

The main reason for revision arthroplasty with an alumina-based prosthesis is aseptic loosening of the prosthesis. To prevent loosening of the prosthesis, endowing bioinert alumina with osteogenic ability is deemed an effective approach. Hence, we developed an alumina substrate with carbonate apatite and evaluated its effectiveness for early binding to the bone. Alumina substrates were coated with carbonate apatite using the following procedures: (1) etching the alumina substrate by alkaline hydrothermal treatment; (2) calcium carbonate coating of the etched alumina substrate; and (3) composition conversion of calcium carbonate coating into carbonate apatite by phosphatization. The tensile bond strength of carbonate apatite coating to alumina substrate was 17.6 MPa, which satisfied the criteria defined by the International Organization for Standardization. Contrary to the results of etched alumina substrates, the carbonate apatite-coated alumina substrates promoted the proliferation and osteogenic differentiation of mesenchymal stem cells and induced mineralization. Furthermore, the carbonate apatite-coated alumina substrates strongly adhered to the rabbit tibia 4 weeks after implantation compared to the etched alumina substrates. The contact area and adhesion strength of carbonate apatite-coated alumina substrates to bone were approximately 19- and 6-fold higher than those of etched alumina substrates, respectively. Thus, carbonate apatite coating may contribute to preventing the loosening of alumina prostheses.

Highly efficient visible light active doped metal oxide photocatalyst and SERS substrate for water treatment.

The development of efficient nanomaterials with promising optical and surface properties for multifunctional applications has always been a subject of novel research. In this work, the study of highly efficient TiO2 nanorods (NRs) and Ta-doped TiO2 NRs (Ta-TiO2 NRs) synthesized by alkaline hydrothermal treatment followed by soaking treatment has been reported. NRs were investigated for their potential applications as recyclable/reproducible visible light active photocatalysts and surface-enhanced Raman scattering (SERS) substrates in wastewater treatment. NRs were characterized by various microscopic (scanning and transmission electron microscopy), spectroscopic (X-ray diffraction, X-ray photoelectron, UV-visible, photoluminescence, and Raman spectroscopy), and surface (Brunauer-Emmett-Teller) techniques. The NRs exhibited promising optical properties with a band gap of 2.95eV (TiO2 NRs) and 2.58eV (Ta-TiO2 NRs) showing excellent photo-degradation activities for methylene blue (MB) dye molecules under natural sunlight. Particularly, Ta-TiO2 NRs showed enhanced response as visible light active photocatalysts in normal sunlight and also as SERS substrate attributed to the additional defects introduced by Ta doping. It could be explained by the combined effect of doping-induced enhanced visible light absorption and charge transfer (CT) properties of Ta-TiO2 NRs. Furthermore, Ta-TiO2 NRs were investigated for their long-term stability, reproducibility of the data, and recyclability in view of their potential applications in water treatment.

SrTiO3 catalysts prepared from topochemical conversion of Bi4Ti3O12 nanoplatelets: Surface characterizations and interactions with isopropanol

The heterostructural Bi4Ti3O12-SrTiO3 (or BIT-STO) platelets with various STO contents (i.e., 40, 65, and 100%) were synthesized by the topochemical conversion of well-defined BIT platelets via the alkaline hydrothermal treatment. The surface properties of synthesized BIT-STO platelets were characterized, and probed by the temperature-programmed surface reaction of isopropanol (IPA). It is found that all BIT-STO catalysts are highly selective in IPA dehydrogenation (to yield acetone) as opposed to IPA dehydration (to yield propene). With the increase in STO content, the desorption temperature of acetone from the BIT-STO surface gradually decreases, suggestive of an improved IPA dehydrogenation activity. The BIT-derived STO exhibits much higher activity and selectivity in IPA dehydrogenation in comparison to the hydrothermally-synthesized STO and commercial STO, which is attributed to the desirable (100) facet with abundant surface defects formed during the topochemical conversion. In-situ infrared spectroscopy indicates that upon IPA adsorption, the BIT-derived STO shows a higher proportion of bridged isopropoxide (IPO) presents on the surface than the reference STO samples. It is proposed that the abundant oxygen vacancies present on the surface of BIT-derived STO could facilitate the bridged adsorption of IPO intermediate that favors further decomposition into acetone, thus promoting the selective IPA dehydrogenation.

Hydrothermal Modification of Chabazite for the Fixation of Cesium Ions

During the accident at the Fukushima Dai-ichi Nuclear Power Plant at March 2011, radioactive cesium (137Cs), which has a long half-life of about 30 years, was released into the environment around the plant. Therefore, methods for the recovery and fixation of 137Cs are required. The CHA-type zeolite, chabazite, has high Cs+ selectivity; Cs+ ions have a diameter of approximately 0.36 nm and can thus enter into and be adsorbed by chabazite, which contains pores with diameters of 0.38 nm. However, some Cs+ ions in the large pores may be released by cation exchange in solutions with a high cation concentration. The ANA-type zeolite (ANA) has pores with 0.28 nm diameters, which are smaller than the diameter of Cs+ ions. ANA is synthesized by an alkaline hydrothermal treatment of natural zeolites such as clinoptilolite, mordenite, and chabazite. This hydrothermal modification may be useful for the fixation of Cs+. In the present study, the modification of chabazite exchanged with Cs+ to produce ANA by hydrothermal treatment was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX), and the solution stability of Cs+ in the ANA was also evaluated using inductively coupled plasma-mass spectrometry (ICP-MS). Modification of chabazite exchanged with Cs+ to produce single-phase ANA was confirmed in a 1.0 mol/L NaOH solution held at 200 °C for 3 to 144 h. The intensity of XRD peaks corresponding to (211) and (220) planes decreased with increasing Cs+ concentration. SEM observations showed that the ANA crystals had a trapezohedral shape and a size of about 5 µm. EDX analysis of ANA crystals confirmed the presence of Cs+. The amount of Cs+ eluted from ANA in a 0.6 mol/L NaCl solution was less than 1.7%.

From biomass to humic acid: Is there an accelerated way to go?

Acid hydrothermal treatment of biowaste is favorable for producing hydrochar and corresponding hydrothermal solution containing saccharides, furans and aromatic compounds, while the alkaline hydrothermal condition is beneficial for their humification to form hydrothermal humic acid (HHA). Herein, the humification potential of hydrochar, hydrothermal solution, and their mixture under alkaline hydrothermal conditions was compared to further reveal their contribution to HHA. The result showed the main source of HHA was hydrochar, occupying 70 wt% of total HHA yield from their mixture while hydrothermal solution only contributed 17 wt%. Moreover, the HHA that existed in hydrochar (denoted as HHAacid) was 32 wt% while the hydrochar-derived HHA obtained after alkaline hydrothermal treatment (denoted as HHAalk) increased to 65 wt%, close to that from commercial coal or lignite. The hydrochar was further separated into four components, i.e. hydrothermal fulvic acid (HFA), stable HHAacid (S-HHAacid) non-stable HHAacid (N-HHAacid) and remaining substance (RS), aiming to reveal the major pathway of the incremental HHA production under alkaline hydrothermal condition. Reactions of RS + HFA, RS + N-HHAacid and self-synthesizing of RS all contributed to the incremental HHAalk yield with the major contribution (75C%) from the first combination (RS + HFA). The pathways of alkaline hydrothermal humification of hydrochar were revealed after analyzing the molecular level structure of HHAalk by UPLC-MS. This in-depth analysis fills the knowledge gap in the mechanism of hydrothermal humification of biowaste.

Enhancement of heavy metal immobilization in sewage sludge biochar by combining alkaline hydrothermal treatment and pyrolysis

Heavy metals, including Cd, As, Ni, Cu, Pb, Cr, Zn, and Mn in sewage sludge (SS) are among the greatest impediments to SS application because of their potential toxicity to living organisms and latent environmental pollution risks. In this study, hydrothermal treatment (HT)/alkaline HT combined with pyrolysis was used to treat SS for heavy metal immobilization. The heavy metal characteristics, including total, fraction, and leaching concentrations and potential ecological risks, were comprehensively investigated to ensure the safe application of biochar. The results showed that the heavy metals mainly remained in the hydrochar and biochar. Additionally, both HT and alkaline HT promoted the residual fractions of Cr, Zn, Ni, and Cu in biochar. Furthermore, alkaline HT-aided pyrolysis was more effective for immobilizing Zn and Ni with their residual fractions increasing by 100% and 60% respectively, compared with direct sludge pyrolysis. Moreover, the ecological risk of heavy metals in SS significantly decreased from 57.27 to 30.05 after alkaline HT-combined pyrolysis treatment, contributing to the low potential ecological risk of SS-based biochar. This study provides a promising strategy for converting SS to biochar with improved heavy metal immobilization.

Reactivity of clay minerals of the Eocene Esmeraldas Formation rocks of the Middle Valley Magdalena Basin (Colombia) in brines and alkaline solutions

The present work focused on understanding the interaction between clay minerals with alkaline fluids used in the oil industry. For this, a comparative study was conducted where the reaction of three rocks belonging to the Eocene Esmeraldas Formation was observed under two experiments. One of these tests consisted of a hydrothermal treatment at static conditions solutions with different concentrations of sodium hydroxide at different interaction times and constant temperature. In parallel, core-flooding tests were carried out, where the original conditions to which these rocks are subjected in the well were considered. Both the original and treated samples were examined by X-ray powder diffraction (XRPD) and Scanning Electron Microscopy (SEM) and the standard test method for Methylene Blue Index to determine the changes that these minerals underwent upon contact with high pH alkaline fluids. As a result, zeolite Linde Type A (LTA), sodalite (SOD) and cancrinite (CAN) formed after alkaline hydrothermal treatment under static conditions, which coincided with the dissolution of kaolinite and smectite. In contrast, core-flooding tests did not show the appearance of zeolites; but dissolution of smectite and kaolinite was observed, in addition to the appearance of an unidentified crystalline phase. The concentration of the alkaline solution and reaction time influenced the dissolution of clays. On the other hand, the cation exchange capacity (CEC) increased at lower concentrations and short reaction times in hydrothermal treatments, which is explained by the appearance of zeolite LTA. Core-flooding tests did not yield the same results as alkaline hydrothermal treatments. It is due to the continuous flow of the alkaline solution through the core plugs that did not allow the polymerization of dissolved aluminosilicate material.

Fly-ash derived Na-P1, natural zeolite tuffs and diatomite in motor oil retention

Aluminosilicate materials of various grain sizes, i.e., Kimolos, Samos and Sorano zeolite tuffs, Samos diatomite and synthetic zeolite prepared from Meliti fly ash via alkaline hydrothermal treatment, were tested as new sorbents for oil leakage remediation. Two lubricant oils of different viscosity, i.e., SHELL HELIX HX5 20 W-50 and ULVAC SMR-100 were selected as potential adsorbates. All sorbents employed demonstrated exceptional oil retention capacity values exceeding 100% (w/w); specifically, Kimolos and Sorano zeolites as well as thermally treated Samos diatomite proved best reaching 160% (w/w) oil sorption. Mordenite and phillipsite were mostly detected in Kimolos and Italian zeolite tuffs, respectively. Na-P1 zeolite, produced for the first time from Meliti fly ash without pretreatment via a low-temperature hydrothermal procedure, was characterized by XRD and SEM. The zeolitization process, leading to Na-P1 as the sole synthesis product, was carried out without the use of additives. The synthetic Na-P1 zeolite displayed significant sorption capacity, retaining 125 and 105% (w/w) of the viscous and less viscous oils tested, respectively. Thus, valorization of all aluminosilicate materials employed was achieved. Both porosity measurements and SEM micrographs demonstrated that the highest lubricant oil retention values were reached by macroporous adsorbents having open structure and large surface area, suitable for overcoming the fluid’s resistance to flow and avoiding pore-blocking effects.

Debromination process of Br-containing PS of E-wastes and reuse with virgin PS

High Br-containing polystyrene (PS) plastics are generated in large quantities during the dismantling of waste CRT TVs. Debromination and reuse of Br-containing PS plastics is a critical technical challenge. Here, we demonstrate a method for combining alkaline hydrothermal debromination and co-blending granulation to achieve the regeneration of high Br-containing PS plastics. The results show the bromine concentration in PS was reduced from 49,300 mg/kg to 7420 mg/kg and from 169,000 mg/kg to 9340 mg/kg, with a removal efficiency of 84.95% at least. Then, we co-blended the debromination PS products (1 part) with qualified normal PS plastics (9 parts) for granulation. Compared to the qualified normal PS, the physical properties of the co-blended plastics remained stable in terms of the melt index, tensile strength, flexural strength andflexural modulus, which made it have good application prospects. Meanwhile, the Br concentration of co-blended PS plastics were further reduced to less than 1000 mg/kg. In summary, we provide a promising outlook of alkaline hydrothermal and co-blending (1 +9) granulation as an efficient approach for Br-containing PS plastics upgrading recycling. Novelty statementThis study provides a novel method for combining alkaline hydrothermal treatment and co-blending modification granulation process to achieve the upgrading recycling of Br-containing waste plastics. The results show the Br concentration in PS was reduced from 169,013 ppm to 9344 ppm, with a removal efficiency of 94.47%. The debromination PS products (1 part) were blended with qualified normal PS plastics (9 parts) for granulation. Compared to the qualified normal PS, the physical properties of the co-blended plastics remained basically stable, which made it have good application prospects. Also, the reuse of waste plastic can make contribution for the carbon reduction.

Hydrothermal Extraction of Amorphous Silica from Locally Available Slate

Slate is a naturally available aluminous silicate based material and can be used as a good source for silica extraction. In the current investigation, the slate sample was passed through calcination and acid leaching processes to decrease alumina contents and other major constituents. Silica extraction was performed by alkaline hydrothermal treatment of a given slate sample followed by acidic precipitation. Different steps, including the effect of concentration of sodium hydroxide solution, reaction time, the ratio of the mass of sample to volume of alkaline solution, the temperature of dispersion, and pH of the filtrate, were investigated to extract the maximum amount of pure amorphous silica. The extracted silica was physicochemically analyzed through XRF, XRD, FT-IR spectroscopy, and SEM techniques. The amorphous nature of the extracted silica is evident from XRD and SEM studies, while FT-IR studies support its purity, showing peaks of only Si–O–Si bonds. The purity of the extracted silica was further confirmed via XRF spectroscopic analysis and a hydrofluoric acid test.

Enhancement of the photocatalytic response of Cu-doped TiO2 nanotubes induced by the addition of strontium

The influence of adding strontium to Cu-doped TiO2 nanotubes on the photocatalytic performance of the resulting materials was herein studied considering changes in structural, textural, optical and morphological properties. Addition of strontium was performed in a 0.2–1.0 wt% range while an optimized fixed Cu loading of 0.5 wt% was used. TiO2 nanotubes were obtained using alkaline hydrothermal treatment of P25 followed by a calcination treatment at 400 °C. The resulting TiNT material was then impregnated with copper using an incipient wetness impregnation followed by a new calcination at 400 °C (0.5Cu-TiNT). Strontium was then added under similar impregnation-calcination conditions. The effect of adding various amounts onto 0.5Cu-TiNT was therefore deeply characterized using X-ray diffraction, N2 adsorption–desorption measurements, scanning electron microscopy coupled with energy-dispersive X-ray analysis, Raman, UV–vis diffuse reflectance, X-ray photoelectron, and photoluminescence spectroscopies as well as determining dielectric properties.Results clearly emphasize that up to a Sr loading of 0.8 wt%, the addition of Sr results in in situ formation of Sr-O-Ti entities on the surface of 0.5Cu-TiNT. Above this threshold loading, excess Sr loading leads to the formation of segregated SrO species. Finally, a direct correlation was observed here between the optimized formation of surface Sr-O-Ti entities and an enhanced photocatalytic response due to improved stabilization of photogenerated charges on 0.5Cu-TiNT resulting from the ferroelectric interference of neighboring SrTiO3 entities.

Alkaline Hydrothermal Treatment and Leaching Kinetics of Silicon from Laterite Nickel Ore

Alkaline Hydrothermal Treatment and Leaching Kinetics of Silicon from Laterite Nickel Ore