Preparation of dual-use GPTES@ZnO photocatalyst from waste warm filter cake and evaluation of its synergic photocatalytic degradation for air-water purification

Photocatalytic Degradation of Organic Pollutants by Sulfate Radicals Activated by Defective NH2-MIL-88B

Photocatalysis has been recognized as a viable technology for pollutant degradation in wastewater, owing to its ability to generate reactive radicals under photoirradiation. Among these, sulfate radicals ( S O 4 · - ) have been attracting significant attention due to their strong oxidizing properties; yet the specific mechanism of action has remained elusive thus far. In this study, defective NH2-MIL-88B (DNMB) is prepared via a facile hydrothermal procedure in the presence of potassium sodium tartrate and found to facilitate the production of sulfate radicals from sulfate anions under visible light irradiation, due to partial reduction of Fe3+ to Fe2+ in the NMB skeleton by the added tartrate that enriches the Fe3+/Fe2+ redox couples, in addition to other reactive species like superoxide radicals and hydroxy radicals. This effectively improves the degradation efficiency toward a variety of organic pollutants, including antibiotics such as tetracycline (TC), sulfamethoxazole (SMX), and levofloxacin (LEV), as well as common organic contaminants like bisphenol A (BPA) and rhodamine B (RhB), as compared to pristine NMB. Specifically, after 40 minutes of visible light irradiation, the degradation rate increases from 61.5% to 92.1% for TC, from 76.1% to 89.4% for SMX, from 60.5% to 75.2% for LEV, from 61.7% to 91.2% for BPA, and from 78.4% to 94.8% for RhB. The primary active species are identified to be sulfate radicals, with minor contributions from holes, superoxide radicals, and hydroxyl radicals, as demonstrated in quenching experiments and electron spin resonance measurements, and further confirmed by theoretical studies. Degradation pathways for the various pollutants are then proposed based on results from Fukui index calculations and liquid chromatography-mass spectrometry analysis. These results underscore the crucial role of structural engineering in driving the advancement of green and sustainable technologies for environmental engineering.

Utilizing triethylenetetramine-functionalized MIP-206 for highly efficient removal of Pb(II) from wastewater

The global concern over heavy metal pollution necessitates urgent measures to safeguard human health and the environment. This study focuses on employing triethylenetetramine (TETA)-functionalized MIP-206-OH (TMIP-206) as an effective adsorbent for removing Pb(II) from wastewater. TMIP-206 was synthesized via a hydrothermal method followed by functionalization with TETA. Kinetic studies demonstrate that lead removal on TMIP-206 conforms to the pseudo-second-order model, indicating an efficient removal process. Experimental results reveal that TMIP-206 aligns with the Langmuir isotherm, exhibiting a maximum removal capacity of 267.15 mg/g for lead ions. The sorption efficiency of TMIP-206 for Pb ions remains stable across six cycles, with a reduction of less than 15%. Optimal adsorption performance is observed at a pH of 6. These findings underscore the potential of TMIP-206 as an alternative for adsorbing Pb(II) from aqueous environments, addressing the global challenge of heavy metal pollution. Future research should explore the scalability and long-term stability of TMIP-206-based adsorbents to enhance their practical applicability in diverse environmental contexts and contribute to broader strategies for mitigating heavy metal contamination.

Self-doping synthesis of nano-TiO2 with outstanding antibacterial properties under visible light

Nano-TiO2 photocatalysis technology has attracted wide attention because of its safety, nontoxicity and long-lasting performance. However, traditional nano-TiO2 has been greatly limited in its application because its wide band gap can only be activated by ultraviolet light (λ < 387 nm). In this paper, nano-TiO2 was prepared by self-doping method. The synthesized nano-TiO2 was a single anatase crystal type with a particle size of 10 nm and uniform size. In addition, nano-TiO2 has high stability and good dispersion. More importantly, nano-TiO2 exhibits excellent visible light (400-780 nm) activity due to the decrease of bandgap from 3.20 eV to 1.80 eV (less than 2.0 eV) and the presence of a large number of hydroxyl groups on the surface of the nanoparticles. In the antibacterial test, the antibacterial rate of both E.coli and S.aureus was close to 100 % under the irradiation of household low-power LED lamps, showing excellent antibacterial performance, indicating that the prepared nano-TiO2 has broad application prospects in the field of bactericidal and bacteriostatic.

A Review of Synthesis Methods, Modifications, and Mechanisms of ZnO/TiO2-Based Photocatalysts for Photodegradation of Contaminants

The environment being surrounded by accumulated durable waste organic compounds has become a critical crisis for human societies. Generally, organic effluents of industrial plants released into the water source and air are removed by some physical and chemical processes. Utilizing photocatalysts as cost-effective, accessible, thermally/mechanically stable, nontoxic, reusable, and powerful UV-absorber compounds creates a new gateway toward the removal of dissolved, suspended, and gaseous pollutants even in trace amounts. TiO2 and ZnO are two prevalent photocatalysts in the field of removing contaminants from wastewater and air. Structural modification of the photocatalysts with metals, nonmetals, metal ions, and other semiconductors reduces the band gap energy and agglomeration and increases the affinity toward organic compounds in the composite structures to expand their usability on an industrial scale. This increases the extent of light absorbance and improves the photocatalytic efficiency. Selecting a suitable synthesis method is necessary to prepare a target photocatalyst with distinct properties such as high specific surface area, numerous surface functional groups, and an appropriate crystalline phase. In this Review, significant parameters for the synthesis and modification of TiO2- and ZnO-based photocatalysts are discussed in detail. Several proposed mechanistic routes according to photocatalytic composite structures are provided. Some electrochemical analyses using charge carrier trapping agents and delayed recombination help to plot mechanistic routes according to the direction of photoexcited species (electron-hole pairs) and design more effective photocatalytic processes in terms of cost-effective photocatalysts, saving time and increasing productivity.

Ionic liquids adsorption and interfacial tension reduction for synthetic resinous and asphaltenic oils: salinity and pH effects

The effects of sulfate salts under low and high salinity conditions and pH of 3.5-11 on interfacial tension (IFT) reduction and IL adsorption using resinous (RSO) and asphaltenic (8 wt/wt%) synthetic oils are investigated. The measurements showed the increasing effect of pH on the IFT of RSO/DW from 23.5 to 27.3 mN/m (pH = 3.5 → 7) in the first place and a reducing effect (0.4 mN/m) if pH = 7 → 11. Using a high concentration of 50,000 ppm for MgSO4, and Na2SO4 revealed an extensive IFT reduction for a pH value of 11 with the value of 0.20 mN/m for Na2SO4. The measured IFT values showed the significant impact of IL (500 ppm) on the IFT (minimum value of 0.01 mN/m for RSO/50,000 Na2SO4 + 500 ppm 1-decyl-3-methyl imidazolium triflate ([C10mim][TfO])) for pH = 11. The IL adsorption measurements showed the role of in-situ surfactant production (saponification process) on the 1-decyl-3-methyl imidazolium chloride ([C10mim][Cl]) and [C10mim][TfO] adsorption reduction from 3.67 to 2.33 and 4.21 to 3.34 mg IL/g rock, respectively. The performed core flooding experiments using the optimum chemical formulation showed the possibility of tertiary oil recovery with maximum oil recovery of 28.8% based on original oil in place in the presence of 500 ppm.

Investigating the Structure and Properties of Epoxy Nanocomposites Containing Nanodiamonds Modified with Aminoacetic Acid

This paper presents a study on the prospects of functionalizing nanodiamonds (NDs) with aminoacetic acid to obtain high-strength composites based on an epoxy matrix. The impact of the functionalization of the ND surface with aminoacetic acid in various concentrations on the properties of the epoxy composite was assessed. The success of grafting amine onto the ND surface was confirmed by X-ray phase analysis and IR spectroscopy. The results show a significant decrease in the average size of ND particles, from 400 nm for the pristine ones to 35 nm, and the contact angle, from 27° to 22°, with an increase in the specific surface area after treatment with a 5% solution of aminoacetic acid. Reducing the average size of NDs allows them to be better distributed throughout the epoxy matrix, which, as a result of the formation of chemical interaction at the matrix-nanofiller phase interface, can significantly increase the strength of the obtained composite. The addition of NDs treated with aminoacetic acid ensures an increase in the deformation-strength properties of epoxy composites by 19-23% relative to an epoxy composite containing the pristine NDs. Moreover, the presence of functionalized NDs significantly influences the structure and thermal stability of the epoxy nanocomposite.

Synthesis of colloidal silica nanofluid and assessment of its impact on interfacial tension (IFT) and wettability for enhanced oil recovery (EOR)

Ever-increasing global energy demand, from one hand and reduced oil initially in place in oil reservoirs due to production and reduced natural reservoir production capacity, on the other hand, has encouraged researchers to investigate different methods to improve and increase enhanced oil recovery (EOR) from oil reservoirs. One method is to employ nanotechnology in injected water, where nanoparticles could affect interfacial tension (IFT) between water and oil and wettability through properties, including high specific surface area and nanoparticle size. However, a major challenge in using nanoparticles in injected water is the instability of these particles in water, which ultimately reduces the efficiency of EOR. These particles cannot be stabilized through conventional methods at a large scale. In this study, stabilized silica nanoparticles were synthesized in the water phase using sodium silicate and sol-gel processes. The stability of this nanofluid was studied in seawater, and then its effect on IFT and changing wettability was examined. According to the results, seawater containing 40 times diluted nanofluid could obtain 41% reduced IFT and 40% alteration in wettability of carbonate core becoming more water-wet and ultimately 13.7% improved final oil recovery in secondary oil recovery and 8.3% improved final oil recovery in third EOR.

The Addition of Co into CuO-ZnO Oxides Triggers High Antibacterial Activity and Low Cytotoxicity

In the present work, a simple two-step method is proposed for mixed oxide synthesis aimed at the achievement of antibacterial nanomaterials. In particular, Cu, Zn and Co have been selected to achieve single-, double- and triple-cation oxides. The synthesized samples are characterized by XRD, IR, SEM and EDX, indicating the formation of either crystalline or amorphous hydrocarbonate precursors. The oxides present one or two crystalline phases, depending on their composition; the triple-cation oxides form a solid solution of tenorite. Also, the morphology of the samples varies with the composition, yielding nanoparticles, filaments and hydrangea-like microaggregates. The antibacterial assays are conducted against E. coli and indicate an enhanced efficacy, especially displayed by the oxide containing 3% Co and 9% Zn incorporated into the CuO lattice. The oxides with the highest antibacterial properties are tested for their cytotoxicity, indicating a low toxicity impact, in line with literature data.

Chemical/photochemical functionalization of polyethylene terephthalate fabric: effects on mechanical properties and bonding to nitrile rubber

The aim of this work is to compare the effects of chemical and photochemical functionalization on the mechanical properties of PET fabric and its adhesion to nitrile rubber (NBR). The photochemical functionalization was performed by UV irradiation of PET fabric in the presence of glutaric acid peroxide at a temperature of 60 °C for different exposure times (i.e. 60, 90 and 120 min). The chemical functionalization (i.e. hydrolysis) of PET fabrics was performed by NaOH solution at a temperature of 60 °C for different times (i.e. 60, 120, 240 and 360 min). The tensile properties of the functionalized fibers were also evaluated. The functionalized PETs were evaluated for H-pull and T-peel adhesion to NBR. It was found that both treatment methods created functional groups on the PET surface. However, carboxylation of PET under GAP/UV irradiation generated much more OH groups on the PET surface (i.e. 4.5 times). The hydrolysis of PET in NaOH solution for more than 60 min caused a significant decrement in the tensile strength contrary to carboxylation under GAP/UV irradiation. It was also found that pullout and T-peel adhesions to NBR decreased in the case of hydrolysis of PET while they increased about 33 and 12% for GAP/UV irradiated PET, respectively.