Mineralization of SF6 and NF3 fluorinated compounds for greenhouse gas abatement by oxalates.

Fluorinated compounds (FCs) such as sulfur hexafluoride (SF6) and nitrogen trifluoride (NF3) have garnered attention due to their environmental impact. This study investigates the mineralization and removal of two potent FCs: SF6 and NF3. The results confirm that utilizing various oxalate salts leads to the formation of corresponding metallic fluorides: lithium fluoride (LiF), sodium fluoride (NaF), and potassium fluoride (KF), validating the occurrence of mineralization reactions. Among the oxalate salts, sodium oxalate demonstrates the highest mineralization efficiency in both SF6 and NF3 removal. Real-time Fourier transform infrared spectroscopy (FT-IR) gas-phase analysis confirms rapid and complete gas removal within a short reaction time using the selected oxalate salts. Meticulous mass balance calculations revealed that oxalates (LiF, NaF, and KF) yielded sulfur (S) at rates of 92.09%, 91.85%, and 84.98% following SF6 mineralization. Additionally, the conversion rates of oxalates to the corresponding metallic fluorides (LiF, NaF, and KF) after SF6 mineralization were 98.18%, 95.82%, and 95.21%, respectively. Similarly, after NF3 mineralization, these conversion rates stood at 92.18%, 90.67%, and 90.02%, respectively. The removal efficiencies for SF6 (1000 ppm) were 4.98, 12.01, and 7.23 L/g, while those for NF3 (1000 ppm) were 14.1, 12.6, and 11.7 L/g, respectively. Notably, sodium oxalate exhibits superior effectiveness, achieving 100% SF6 conversion within 30 min and 100% NF3 conversion within 50 min. This work underscores the potential of oxalate mineralization as a promising strategy for efficient and rapid removal of potent fluorinated compounds, paving the way for environmentally benign FC remediation techniques with broader implications for sustainable gas treatment technologies.

Green synthesis and characterization of silicate nanostructures coated with Pluronic F127/gelatin for triggered drug delivery in tumor microenvironments.

Thermo-/pH-sensitive nanocomposites based on mesoporous silicate MCM-41 (MSNCs) derived from rice husk ash were synthesized and characterized. MSNCs were coated with thermo-/pH-sensitive Pluronic® F127 and gelatin to form MSNCs@gp nanocomposites, serving as carriers for controlled release of the anticancer drug doxorubicin (Dox). The in vitro and in vivo antitumor efficacy of MSNCs@gp-Dox against liver cancer was evaluated. Fourier-transform infrared (FTIR) spectra confirmed the silica nature of MSNCs@gp by detecting the Si-O-Si group. Under acidic microenvironments (pH 5.4) and 42 °C, MSNCs@gp-Dox exhibited significantly higher Dox release (47.33 %) compared to physiological conditions. Thermo-/pH-sensitive drug release (47.33 %) was observed in simulated tumor environments. The Makoid-Banakar model provided the best fit at pH 7.4 and 37 °C with a mean squared error of 0.4352, an Akaike Information Criterion of 15.00, and a regression coefficient of 0.9972. Cytotoxicity tests have demonstrated no significant toxicity in HepG2 cells treated with various concentrations of MSNCs@gp, while MSNCs@gp-Dox induced considerable cell apoptosis. In vivo studies in nude mice revealed effective suppression of liver cancer growth by MSNCs@gp-Dox, indicating high pharmaceutical efficacy. The investigated MSNCs@gp-based drug delivery system shows promise for liver cancer therapy, offering enhanced treatment efficiency with minimal side effects.

Synthesis and characterization of green rust-deposited MoS2 composites for adsorptive removal of EDTA-chelated Ni(II) in wastewater.

Ethylenediamminetetraacetatonickel(II) (EDTA-Ni(II)) has emerged as a significant soil and groundwater contaminant due to the increasing agricultural and industrial activities, posing environmental challenges. This study focuses on addressing the reactivity of green rust (GR), which can be hindered by oxidation with oxygen, limiting its effectiveness in remediation processes. To overcome this limitation and enhance the adsorptive capacities, the combination of sulfate green rust (SO4-GR) with various Fe(II)/Fe(III) ratios with a high-surface-area adsorbent, MoS2, resulting in the formation of binary composites of green rust-deposited MoS2 (MSGs) were explored. The aim was to improve the removal efficiency of EDTA-Ni(II) from contaminated wastewater. To characterize the MSGs, a comprehensive analysis using XRD, SEM, TEM, FTIR, and X-ray absorption spectroscopy was performed. The surface areas of the MSGs were smaller than that of MoS2 but larger than that of the SO4-GRs, indicating a promising composite material. XANES spectra analysis revealed that both MSGs and SO4-GRs exhibited a mixture of ferrous and ferric ions, as evident from their spectral positioning between FeO and Fe2O3. The optimal pH for efficient removal of EDTA-Ni(II) was 3, which resulted in removal efficiencies of 45.6%, 47.3%, 46.0%, and 46.2% for MSG 1, MSG 2, MSG 3, and MSG 4 after 24 h, respectively. Reducing the initial concentration of EDTA-Ni(II) to 50 mg Ni(II)/L effectively doubled the removal efficiency. Notably, as EDTA-Ni(II) was removed, an increased leaching of iron was observed, leading to a total iron concentration exceeding 40 mg/L for the composites with higher Fe(II)/Fe(III) ratios. These findings underscore the potential of MSG as a promising material for degrading EDTA-Ni(II) in contaminated wastewater, offering a viable solution to mitigate the environmental impact of this emerging contaminant. This study contributes to the understanding of green rust reactivity and provides valuable insights for developing effective strategies to address the challenges associated with EDTA-Ni(II) contamination.

Thermal-/pH-triggered hollow mesoporous carbon nanocarrier for NIR-responsive drug release.

Intelligent drug-delivery systems are considered one of the most important techniques for improving cancer treatment using existing over-the-counter medicines. However, metallic materials are always accompanied by metabolism problems, whereas chemotherapy produces several side effects in humans. Carbon-based materials exhibit exceptional features such as bio-affinity and bio-degradability. Herein, hollow mesoporous carbon nanoparticles (HMCs) are reported as effective nanocarriers of anti-cancer small drug molecules. Near IR (NIR) sources, which can penetrate most organs, induce thermal effects via non-invasive pathways. NIR radiation not only provides thermal therapy but also is compatible with temperature-sensitive coated responsive polymer shells. The template method was used to synthesize HMCs with size 200 ± 50 nm, under various conditions, to obtain suitably sized and hollow structures for liver-cancer treatment. Additional pH/thermal-bi-responsive poly(N-isopropylacrylamide) (PNIPAM) shells were further coated onto the HMCs to produce multiple shells that could trigger swelling motions in PNIPAM@HMCs, as confirmed via small-angle X-ray scattering (SAXS). NIR results demonstrated an extreme increase to the ∆T of 8.7 and 14.2 °C for HMC and PNIPAM@HMCs, respectively. The SAXS spectra analyzed using SasView simulations demonstrated the multi-shell structures of synthesized HMCs and the release mechanism of PNIPAM@HMCs. Based on the model simulation of SAXS, the different rates of polymer swelling indicated the core shrinkage (229.7 to 134.2 Å) and shell expansion (324.3 to 514.3 Å) at 37 °C and 42 °C, respectively. In addition, the first-order, Higuchi, Korsmeyer-Peppas, and Weibull mathematical models were used to verify the drug-release kinetics, and the model with the highest R2 value was considered most suitable for further application. This paper presents the first SAXS study on PNIPAM@HMCs release kinetics and related mechanisms. This phenomenon indicates NIR-induced PNIPAM@HMCs as an effective strategy for cancer treatment via doxorubicin release.

Preparation and in-vitro/in-vivo evaluation of doxorubicin-loaded magnetic SBA-15 nanocomposites from rice husk for enhancing therapeutic efficacy.

In recent years, nanoscience has attracted considerable attention in the field of biomedicine. This involves the use of engineered nanomaterials as vital platforms for targeted drug delivery, diagnosis, imaging, and observation of therapeutic efficiency. This study explored the preparation, characterization, and applications of doxorubicin-loaded magnetic rice husk ash-derived SBA-15 (MIO@RHAS15-DOX nanocomposites) for drug delivery and in vitro/in vivo efficiency in the treatment of liver cancer. The small-angle XRD patterns of the MIO@RHAS15 nanocomposites demonstrated a core diffraction peak at 0.94°, with two noticeable peaks at 1.6° and 1.8°, representing (100), (110), and (200) crystalline planes, respectively, thereby indicating the existence of a well-defined mesostructure. A sharp melting endothermic peak (Tm) at 79 °C was observed for MIO@RHAS15 nanocomposites. The DOX release from MIO@RHAS15 followed the Higuchi model with the best correlation coefficient R2 value of 0.9799. The in vitro studies indicated a concentration dependent anticancer efficiency, with high cancer cells inhibition for MIO@RHAS15-DOX than free DOX. At the highest concentration of DOX (120 µg/mL), there was less than 25% and 15% cell viability after 24 h and 48 h, respectively. The in vivo studies demonstrated that the tumor sizes after treatment with PBS, MIO@RHAS15, free DOX, and MIO@RHS15-DOX were 1081, 904, 143, and 167 mm3, respectively. The in vivo animal test results depicted that the MIO@RHAS15-DOX nanocomposites were able to inhibit liver tumors in all tested mice. Therefore, the prepared nanocomposites possess a great potential for drug delivery application towards cancer treatment, thereby overcoming the limitations of traditional chemotherapy.

Design of doxorubicin encapsulated pH-/thermo-responsive and cationic shell-crosslinked magnetic drug delivery system.

The upsurge in cancer cases, such as liver cancer, has claimed millions of lives globally and has prompted the development of novel nanodrug delivery systems. These systems allow cancer drugs to be encapsulated in nanocarriers and delivered to tumor sites, and accordingly, help reduce side effects of the current chemotherapeutic treatments. Herein, we prepared nanocarriers comprising magnetic iron oxide (MIO) nanoparticles that were surface modified with crosslinked Pluronic F127 (PF127) and branched polyethylenimine (bPEI) to form MIOpoly nanocarriers. These nanocarriers were then loaded with doxorubicin (DOX) anticancer drug to form the MIOpoly-DOX complex. The nanocarriers were magnetite and possessed superparamagnetic properties. Small-angle neutron scattering (SANS) analysis indicated that the nanocarriers were thermoresponsive and spherically structured. The characteristic peaks at 1285, 1619, 2844, 2919, 2900, 2840, and 3426 cm-1, corresponding to those of CN, -NH2, -CH2, and OH-, confirmed the successful crosslinking, coating of PF127-bPEI polymers on the surface of MIO nanoparticles and DOX conjugation. The bioavailability of the nanocarriers indicated a more than 85% cell viability when using HepG2 liver cancer cells. A pH (54.8% release in 48 h; pH = 5.4) and temperature (51.0% release in 48 h; 42 °C)-dependent release of DOX was observed, displaying a Korsmeyer-Peppas kinetics model at low pH and Weibull model at high temperatures. The high DOX fluorescence observed for MIOpoly-DOX indicated a high cellular uptake enhanced by alternating magnetic field. These results suggest that MIOpoly synthesized using a combined approach of surface crosslinking and grafted with PF127-bPEI appear to offer promising properties as drug delivery system. Therefore, the nanocarriers developed in the study possess a great potential for targeted delivery and thereby circumventing the limitations of conventional chemotherapy.

De novo synthesis of a MIL-125(Ti) carrier for thermal- and pH-responsive drug release.

Microporous round cake-like (diameter: 900 ± 100 nm) MIL-125(Ti) carrier with a central metal (Ti) exhibiting bio-affinity and possessing a great potential to be used as drug release platform, has been synthesized in the present study. The thermal and pH responsiveness of drug delivery systems (DDS) are the most important parameters for drug release and can be provided through polymer coating techniques. The Pluronic F127 (F127) and chitosan (CH) monomers were inserted into the crystal lattice of MIL-125(Ti) carrier during the de novo synthesis process, which were subsequently loaded with doxorubicin (DOX). The results reveal particle size changes (ranged between 30 and 50 %) from the original size of the MIL-125(Ti) carrier in response to temperature and pH when the carrier reaches acid environment. The drug release profiles have been completed through self-design device, which provides for the real-time release in the DOX amounts via UV-Vis spectra. The kinetics analysis was used to evaluate the R2 values of first order, Higuchi, Korsmeyer-peppas, and Weibull fitting equations, where the Weibull fitting indicated the best R2. An increase by 59.3 % of DOX released under the acid status (pH = 5.4) was observed, indicating that the CH-MIL-125(Ti) carrier is temperature and pH responsive. Moreover, the lattice explosion resulting from the temperature increase in the range of 25-42 °C caused an increase in F127-MIL-125(Ti) by 30.8-38.3 %. The simulated SAXS/WAXS studies for the microstructures of MIL-125(Ti) based DDS at different temperatures after polymer coating (F127-MIL-125(Ti)) provide the possible mechanism of lattice explosion. As such, the responsive Ti-MOF has a highly potential for use in the applications of cancer treatment.

Bioaccumulation of trace metals and speciation of copper and zinc in Pacific oysters (Crassostrea gigas) using XANES/EXAFS spectroscopies.

Copper (Cu) and zinc (Zn) concentrations in oyster soft tissues can be particularly high due to contamination, leading to extremely green/blue colors. This raises key questions regarding the behavior and speciation of trace metals in oyster soft tissues. This study investigated trace metal concentration profiles of contaminated Pacific oyster (Crassostrea gigas) soft tissues collected from trace metal-contaminated coastal area of Xiangshan District using inductively coupled plasma optical emission spectrometry (ICP-OES), energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Moreover, Cu and Zn speciation in contaminated and non-contaminated oyster soft tissues were investigated by X-ray absorption near edge structure spectroscopy/extended X-ray absorption fine structure (XANES/EXAFS) spectroscopic methods. The contents of Cu (1,100-1,400 mg/kg) and Zn (500-700 mg/kg) dry weight were high in oyster soft tissue samples. The XANES/EXAFS results revealed that Cu and Zn existed primarily as copper (II) oxide (CuO) and zinc oxide (ZnO) in contaminated oysters. Furthermore, Cu and Zn formed clusters with Cu-O and Zn-O interatomic distances of 1.97 and 2.21 Å, (coordination numbers 1.0 and 5.6), respectively. In non-contaminated oysters, the less abundant Cu and Zn existed mainly as copper(I) sulfide (Cu2S) and zinc sulfide (ZnS) forming clusters with Cu-S and Zn-S (thiolates) bond distances of 2.09 and 1.23 Å (coordination numbers of 4.6 and 2.4). These results provide further understanding on the chemical speciation of Cu and Zn in contaminated and non-contaminated oyster soft tissues as well as the bioaccumulation of trace metals in the oyster soft tissues.

Speciation and fate of toxic cadmium in contaminated paddy soils and rice using XANES/EXAFS spectroscopy.

The present study was conducted to determine the Cd distribution and speciation in contaminated paddy soils and rice kernels using XANES/EXAFS spectroscopy. The morphology and crystallization of rice and soils were investigated using FE-SEM and XRD techniques. The EXAFS spectra of Cd in soil and rice kernels showed that cadmium oxides (CdO) in soil and rice kernels formed Cd clusters with Cd-O bond distances of 2.35 Å and 2.25 Å (coordination numbers of 2.3 and 3.8), respectively. The XRD patterns show that silica oxide (SiO2, 2θ = 24.2) and aluminum oxide (Al2O3, 2θ = 35.7) were the main components detected. The FE-SEM analysis revealed that the surface characteristics and sizes of the rice kernels are smooth and uneven with particle sizes of 0.5-4 µm, while the soil particles are not uniform and aggregated. Furthermore, the distribution of toxic metals/metalloid (Cd, Pb, Cr, Ni, As, Cu, and Zn) accumulated in the contaminated paddy soils and rice crops were also examined. Interestingly, these results offered an insight into the accumulation mechanism and distribution of heavy metals in contaminated rice farming soils and rice crops.

Speciation and fate of toxic cadmium in contaminated paddy soils and rice using XANES/EXAFS spectroscopy.

The present study was conducted to determine the Cd distribution and speciation in contaminated paddy soils and rice kernels using XANES/EXAFS spectroscopy. The morphology and crystallization of rice and soils were investigated using FE-SEM and XRD techniques. The EXAFS spectra of Cd in soil and rice kernels showed that cadmium oxides (CdO) in soil and rice kernels formed Cd clusters with Cd-O bond distances of 2.35 Šand 2.83 Š(coordination numbers of 2.3 and 4.2), respectively. The XRD patterns show that silica oxide (SiO2, 2θ  = 24.2) and aluminum oxide (Al2O3, 2θ = 35.7) were the main components detected. The FE-SEM analysis revealed that the surface characteristics and sizes of the rice kernels are smooth and uneven with particle sizes of 0.5-4 µm, while the soil particles are not uniform and aggregated. Furthermore, the distribution of toxic metals/metalloid (Cd, Pb, Cr, Ni, As, Cu, and Zn) accumulated in the contaminated paddy soils and rice crops were also examined. Interestingly, these results offered an insight into the accumulation mechanism and distribution of heavy metals in contaminated rice farming soils and rice crops.

In-situ reductive degradation of chlorinated DNAPLs in contaminated groundwater using polyethyleneimine-modified zero-valent iron nanoparticles.

Zero-valent iron nanoparticles (ZVIN) have found applications in many strategies for on-site soil and groundwater decontamination. A number of studies have reported the prospective utilization of ZVIN in the reduction of chlorinated organic compounds such as dense non-aqueous phase liquids (DNAPLs) in groundwater. Due to their bioaccumulation and carcinogenesis, DNAPLs in groundwater are a human health hazard and pose environmental risks. Therefore, decontamination of these contaminants is necessary. This study presents the in-situ remediation of trichloroethylene (TCE), perchloroethene (PCE), and 1,2-dichloroethene (1,2-DCE) DNAPLs through the direct injection of polyethylenimine (PEI)-coated ZVIN (PEI-ZVIN composite materials) to facilitate the reduction of contaminants in low-permeability media. A field test was conducted at the premises of a petrochemical company, situated in the Miaoli County of Northern Taiwan that discharged significant amounts of DNAPLs. After in-situ injection and one-day of reaction with groundwater contaminants, ZVIN was further characterized to examine its efficacy in the reduction of pollutants. After the direct injection of PEI-ZVIN, a notable reduction in the concentration of DNAPLs was recorded with conversion from toxic to non-toxic substances. Use of resistivity image profiling (RIP) technique suggested similar conductivity data for the PEI-coated ZVIN suspension and groundwater samples. X-ray absorption near edge structure (XANES) and X-ray absorption fine structure (EXAFS) studies depicted that the oxidation of ZVIN and PEI-ZVIN was occurring after the reductive reaction with contaminated groundwater. The reacted samples had bond distance values of 1.98, 2.00, 1.96, and 1.94 Å. Combining floating surface-coated ZVIN and RIP technique seems promising and environmentally attractive.