Radiation induced in-situ cationic polymerization of polystyrene organogel for selective absorption of cholorophenols from petrochemical wastewater

Gamma irradiation-enhanced performance of waste LLDPE thermally transformed into advanced sponge-like material for oil decontamination

In this study, the development of advanced materials for the removal of oil-water pollution was explored, with a focus on environmental protection. The primary novelty of this research involved the conversion of waste Linear low-density polyethylene (LLDPE) into a sponge-like material denoted as sLLDPE. The process of converting involved thermal treatment in castor oil, resulting in the creation of a porous structure within the material. This sLLDPE material exhibited remarkable oil adsorbent properties and demonstrated enhanced performance in the removal of various organic contaminants from both aqueous and oil-based systems. Furthermore, gamma irradiation-induced crosslinking reactions were implemented within a dose range of 0 up to 90 kGy to further improve its oil removal capabilities. Comparing samples subjected to a radiation dose of 50 kGy with those receiving no irradiation (0 kGy), it was observed that the maximum adsorption capacities for various oils, including crude oil, gasoline oil, motor oil, pump oil, and waste oil, increased significantly. Specifically, the adsorption capacities increased by approximately 216.2%, 235.3%, 24.1%, 111.5%, and 18.6% for the respective oils. It rapidly separated oil-water mixtures with ~ 100% efficiency in a column system and maintained performance over 20 reuse cycles. The converted sLLDPE sponge exhibited excellent organics removal across solvents. The findings of this study not only shed light on the impact of irradiation on polymeric materials but also contribute to our understanding of their potential applications in environmental cleanup processes.

Regulation of friction pair to promote conversion of mechanical energy to chemical energy on Bi2WO6 and realization of enhanced tribocatalytic activity to degrade different pollutants

Recently, friction-induced tribocatalysis has received tremendous attention through converting mechanical energy to chemical energy. However, its efficiency is much lower than those of photocatalysis and piezocatalysis, and its environmental application is limited in dye degradation. Herein, we developed a facile approach to improve the tribocatalytic activity of Bi2WO6 via adding trace polymer powders to form friction pairs with Bi2WO6. Among various polymers, PTFE was demonstrated to be the best counterpart of Bi2WO6. Subsequently, the PTFE dosage, stirring rate, magnetic bar size and number, and stirring mode were further optimized. The PTFE-promoted Bi2WO6 tribocatalysis was verified to possess excellent performance not only for removing different dyes, but also for degrading chlorophenols that are typical persistent organic pollutants. Multiple uses of the recycled catalysts indicated its good stability and prominent tribocatalytic durability. EPR measurements suggested the generation of hydroxyl radical and superoxide radical, which were determined to be continuously generated within 12 h at the rates of 0.88 μM h-1 and 85 μM h-1, respectively. Subsequently, a possible mechanism was proposed to explain the enhanced performance of the PTFE-promoted Bi2WO6 tribocatalysis. Finally, on basis of the detected intermediates, the degradation pathways of Rhodamine B and 2,4-Dichlorophenol during tribocatalysis were suggested.

Gamma radiation-induced synthesis of novel PVA/Ag/CaTiO3 nanocomposite film for flexible optoelectronics

A flexible nanocomposite film based on polyvinyl alcohol (PVA), silver nanoparticles, and calcium titanate (CaTiO₃) was synthesized using gamma radiation induced-reduction. Temperature-dependent structural, optical, DC electrical conductivity, electric modulus, and dielectric properties of PVA/Ag/CaTiO₃ nanocomposite film were investigated. The XRD pattern proved the successful preparation of the nanocomposite film. Also, as the temperature increases, the average crystallite sizes of CaTiO₃ and Ag nanoparticles decrease from 19.8 to 9.7 nm and 25 to 14.8 nm, respectively. Further, the optical band gap increased from 5.75 to 5.84 eV with increasing temperature. The thermal stability is improved, and the semiconductor behavior for PVA/Ag/CaTiO₃ nanocomposite film is confirmed by thermal activation energy ΔE with values in the 0.11-0.8 eV range. Furthermore, the maximum barrier W_m value was found of 0.29 eV. PVA/Ag/CaTiO₃ nanocomposite film exhibits a semicircular arc originating from the material's grain boundary contributions for all temperatures. The optical, DC electrical conductivity, and dielectric properties of the PVA/Ag/CaTiO₃ nanocomposite film can be suitable for flexible electronic devices such as electronic chips, optoelectronics, and energy storage applications.

Radiation Synthesis of Carbon/Aluminum/Silica Aerogel Nanoporous Structure Derived from Polyacrylamide Hydrogel for High Temperature and Oil Removal Applications

Aerogel is a high-performance thermal resistance material desired for high-temperature applications like dye-sensitized solar cells, batteries, and fuel cells. To increase the energy efficiency of batteries, an aerogel is required to reduce the energy loss arising from the exothermal reaction. This paper synthesized a different composition of inorganic-organic hybrid material by growing the silica aerogel inside a polyacrylamide (PAAm) hydrogel. The hybrid PaaS/silica aerogel was synthesized using different irradiation doses of gamma rays (10-60 kGy) and different solid contents of PAAm (6.25, 9.37, 12.5, and 30 wt %). Here, PAAm is used as an aerogel formation template and carbon precursor after the carbonization process at a temperature of (150, 350, and 1100 °C). The hybrid PAAm/silica aerogel was converted into aluminum/silicate aerogels after soaking in a solution of AlCl₃. Then, the carbonization process takes place at a temperature of (150, 350, and 1100 °C) for 2 h to provide C/Al/Si aerogels with a density of around 0.18-0.040 gm/cm³ and porosity of 84-95%. The hybrid C/Al/Si aerogels presented interconnected networks of porous structures with different pore sizes depending on the carbon and PAAm contents. The sample with a solid content of 30% PAAm in the C/Al/Si aerogel was composed of interconnected fibrils whose diameter was about 50 μm. The structure after carbonization at 350 and 1100 °C was a condensed opening porous 3D network structure. This sample gives the optimum thermal resistance and a very low thermal conductivity of 0.073 (w/m·k) at low carbon content (2.71% at temperature 1100 °C) and high v_pore (95%) compared with carbon content 42.38% and v_pore (93%) which give 0.102 (w/m·k). This is because at 1100 °C, the carbon atoms evolve to leave an area between Al/Si aerogel particles, increasing the pore size. Furthermore, the Al/Si aerogel had excellent removal ability for various oil samples.

Application of Nano-Inspired Scaffolds-Based Biopolymer Hydrogel for Bone and Periodontal Tissue Regeneration

This review’s objectives are to provide an overview of the various kinds of biopolymer hydrogels that are currently used for bone tissue and periodontal tissue regeneration, to list the advantages and disadvantages of using them, to assess how well they might be used for nanoscale fabrication and biofunctionalization, and to describe their production processes and processes for functionalization with active biomolecules. They are applied in conjunction with other materials (such as microparticles (MPs) and nanoparticles (NPs)) and other novel techniques to replicate physiological bone generation more faithfully. Enhancing the biocompatibility of hydrogels created from blends of natural and synthetic biopolymers can result in the creation of the best scaffold match to the extracellular matrix (ECM) for bone and periodontal tissue regeneration. Additionally, adding various nanoparticles can increase the scaffold hydrogel stability and provide a number of biological effects. In this review, the research study of polysaccharide hydrogel as a scaffold will be critical in creating valuable materials for effective bone tissue regeneration, with a future impact predicted in repairing bone defects.

Characterization and distribution of plastic particles along Alexandria beaches, Mediterranean Coast of Egypt, using microscopy and thermal analysis techniques

Microplastics (MPs) contamination has become a global concern with potential impacts on the marine environment. Alexandria is the second-largest city in Egypt and a significant contributor of plastic litter inputs into the Eastern Mediterranean Sea. The current study provides an in-depth analysis of the plastic particles accumulated along Alexandria beaches. Types, composition, and potential sources of MPs were investigated using microscopy and thermal analysis. A mean value of 389.1 ± 285.9 items kg^-1 dry weight was detected in the shore sediments similar to other records from the Eastern Mediterranean region. An average of 457.4 ± 281.8 items m^-3 was recorded in the surface water, which was the highest recorded MPs density in onshore waters of the Mediterranean region. Thermogravimetric analysis (TGA) showed that plastics made up 0.5% - 72% of the materials extracted from the sediment samples, and 0.58% - 20.6% from the water samples. Differential scanning calorimetry (DSC) identified ten semi-crystalline polymers. Low-density polyethylene (LDPE) and polyethylene vinyl acetate (PEVA) were the common polymers. The single-use plastic bags and detergents were the land-based sources of marine plastic litter. The sea-based sources included antifouling paints, maintenance of ships, and abandoned fishing gears. Proper management plans of domestic waste input, polluter-pay strategy, and education programs aiming at the Fishermen and how plastic pollution would impact their livelihood are urgently needed.

Experimental investigation of E-beam effect on the electric field distribution in cross-linked polyethylene/ZnO nanocomposites for medium-voltage cables simulated by COMSOL Multiphysics

This study investigated the electric field distribution of underground cable insulation in cross-linked polyethylene/zinc oxide (XLPE/ ZnO) nanoparticles (NPs) for medium-voltage (MV) cables. The ZnO NPs that were obtained by three methods of preparation were classified using transmission electron microscopy (TEM). The obtained ZnO NPs were semi-spheres with sizes of 35–55 nm on TEM images. XLPE/ ZnO films with various ZnO NP weight contents (i.e., 0, 1, 3, and 5%) were exposed to varied dosages of 3-MeV electron beam (EB); 0 kGy, 15 kGy, 20 kGy, and 25 kGy. The optimum film XLPE/ 5-ZnO, which has ZnO NP content (5 wt%), irradiated at 25 kGy, according to alternating current (AC)/ DC conductivity (AC: 1 × 10−4 S/m; DC: 12.44 × 10−2 S/m) in minimum relative permittivity (2.24), was obtained. COMSOL Multiphysics was used to simulate the electric field distribution within an MV cable of 25-kGy XLPE/ 5-ZnO insulation. The maximum uniform electric field was found in the middle of the 25-kGy XLPE/5-ZnO film sample, rather than at the top or bottom, which might be attributed to the significantly low relative permittivity of the new 25-kGy XLPE/5-ZnO film cable.

Quinoline-cored Poly(Aryl Ether) Dendritic Organogels with Multiple Stimuli-Responsive and Adsorptive Properties

Functional supramolecular gel materials have potential applications in sensors, optical switches, artificial antennae, drug delivery and so on. In this paper, quinoline-cored poly(aryl ether) dendritic organogelators were designed, synthesized and fully characterized. The gelation behaviour of the dendritic organogelator was tested in organic solvents, mixed solvents and ionic liquids. The dendron Q-G1 was found to be an efficient and versatile organogelator toward various apolar and polar organic solvents with the critical gelation concentrations (CGCs) approaching 1.2×10^-2  mol/L, indicating one dendritic organogelator could immobilize 1.2×10³ solvent molecules in the organogel network. Interestingly, these dendrons exhibited excellent gel formation in ionic liquids. Notably, these dendritic organogels were found to display multiple stimuli-responsive properties toward external stimuli including heat, ultrasound and shear stress, with a reversible sol-gel phase transition. In addition, the dendritic organogel could effectively adsorb heavy metals and organic dyes. The removal rate of Pb²⁺ was up to 20% and the adsorption rate for Rhodamine B was as high as 89%.

Photocatalytic and biocidal activities of ZnTiO2 oxynitride heterojunction with MOF-5 and g-C3N4: A case study for textile wastewater treatment under direct sunlight

The work aimed to synthesize three heterojunction photocatalysts (E_g = 2.65-2.78 eV) via in-situ encapsulation of 5% zinc doped titanium oxynitride (Zn_0.05TiO_xN_y) catalyst into MOF-5 and bulk (BCN)/sulfur-doped (SCN) g-C₃N₄ supports using a microwave method. The prepared photocatalysts were characterized and utilized to purify textile industrial wastewater from the organic dye (e.g., methylene blue, MB) and microbial (e.g., E. coli, S. aureus, and C. albicans) contaminants under dark, visible, and solar lights. The output data confirmed the higher activity of Zn_0.05TiO_xN_y@SCN and Zn_0.05TiO_xN_y@MOF-5 for photo-induced microbial growth inactivation (> 90%) under visible light, with photo-biocidal efficiency of 0.91-1.69 mCFU/Einstein. Such a phenomenon is ascribed to the synergism between the high antimicrobial capacity of supports and photoactivity of Zn_0.05TiO_xN_y. Also, Zn_0.05TiO_xN_y@SCN exhibited far superiority to mineralize MB dye (K_photo of 2.73 × 10^-2 min^-1) under direct sunlight due to its high photonic (ζ% of 4.4-8.3%)/quantum (QE of 0.56-0.54%) efficiencies for the generation of hydroxyl and superoxide (^-•O₂/•OH) oxidative species. As a practical case study, all heterojunction photocatalysts also demonstrated high-performance stability (5 cycles) for real textile wastewater treatment under sunlight (efficiency = 76.1-84.6%).

Preparation of hydrophobic macroinimer-based novel hybrid sorbents for efficient removal of organic liquids from wastewater

Herein, the synthesis of hydrophobic macroinimer-based hybrid sorbents and their use in the removal of organic solvents from wastewater is explored. Polydimethylsiloxane (PDMS), 4,-4'-azobis-4-cyanopentanoyl chloride (ACPC), and methacryloyl chloride were reacted via bulk condensation polymerization to synthesize the macroinimer. The organogel systems were then prepared with macroinimer using different acrylic monomers of methyl acrylate, ethyl acrylate, and butyl acrylate without any additional crosslinker and initiator. The structural properties of the obtained final products were characterized by FT-IR, ¹H-NMR, and TGA. The effect of alkyl chain length and macroinimer moieties in the organogel networks, as well as the swelling capacities of the prepared gels, was evaluated for different organic solvents and oils. The maximum solvent absorbencies of macroinimer-based organogels were determined as 85.3%, 100.9%, 1422.1%, 1660.0%, 3809.3%, and 5032.2% for diesel oil, gasoline, acetone, benzene, tetrahydrofuran (THF), and dichloromethane (DCM), respectively. Furthermore, adsorption-desorption kinetics, selective absorption from oil/water mixtures, temperature effect on the absorption capacity, and reusability tests were investigated. Obtained results showed that the prepared organogels possessed high swelling, efficient absorption capacity, and good oil separation performance in the removal of organic solvents from wastewater. The temperature-dependent absorption study shows no significant change in absorption capacity. Thus, the prepared macroinimer-based organogels in the present study demonstrate potential as prospective sorbents for organic pollutant cleanup from wastewater.

A strategy for the efficient removal of chlorophenols in petrochemical wastewater by organophilic and aminated silica@alginate microbeads: Taguchi optimization and isotherm modeling based on partition coefficient

Through in situ encapsulation of cetyltrimethylammonium bromide (CTAB) and urea-functionalized SiO₂ nanoparticles in alginate hydrogel, two types of new functionalized microbeads, CTAB-SiO₂@alginate (organophilic) and urea-SiO₂@alginate (aminated), were produced. Their adsorption behavior toward multiple chlorophenols (CPs: e.g., 4-chlorophenol (MCP), 2,4-dichlorophenol (DCP), and 2,4,6-trichlorophenol (TCP)) in petrochemical wastewater was assessed with the aid of Taguchi's L9 orthogonal array at three levels. In terms of the partition coefficient (PC: μmol/g·μM (or L/g)), the use of three-parameter models (hybrid Langmuir-Freundlich and Redlich-Peterson) yielded the best fit (R² ≈ 1). Furthermore, the performance evaluation in terms of PC metric indicated that CTAB-SiO₂@alginate (7.85 L/g) was better to treat total CPs than urea-modified SiO₂@alginate microbeads (3.83 L/g). The enhanced performance of the former reflects the significant contribution of CTAB functionality (sp² carbon tail and quaternary amine (N⁺) cationic head sites) for accelerating uptake of molecular (or suspended) and ionizable CPs molecules (e.g., with the aid of salting-out effect at a high initial CPs concentration and salinity) via hydrophobic/electrostatic interactions. The high performance of the CTAB-SiO₂@alginate was demonstrated against petroleum hydrocarbons, CPs, and phenol contaminants using real petrochemical wastewater (up to three reusable cycles).

The Green Method in Water Management: Electron Beam Treatment

During the prebiotic era, radiolytic transformations in the oceans played a key role in purifying water from toxic impurities and, thus, played a role in the formation of the aquatic environment of our planet, making it suitable for the emergence of life. Today, the planet again faces the challenge of how to provide people with clean water. Therefore, it is reasonable to look back at past historical stages and again consider the possibility of neutralizing pollutants in water by means of radiolysis, which has already been tested by time. Modern radiolytic treatments can be much faster and safer thanks to the advent of powerful electron accelerators and high-rate electron beam treatment (ELT) of water and wastewater. Radiolytic treatment of water using accelerated electrons corresponds to the essence of advanced oxidative technologies and green chemistry. The ELT of water instantly generates a high concentration of short-lived radicals that can quickly neutralize and decompose chemical and bacterial pollutants. Due to the ability of accelerated electrons to penetrate into a substance, ELT provides the decomposition of both dissolved and suspended pollutants. The cleaning effect of ELT is due to the ability to inactivate toxic and chromophore functional groups, transform impurities into an easily removable form, damage the DNA of microorganisms and their spore forms, and increase the biodegradability of organic impurities. The use of ELT in water treatment provides significant savings in chemical reagents, thereby improving quality and reducing the number of cleaning steps. The compactness, high degree of automation of the equipment used, energy efficiency, high productivity, and excellent compatibility with traditional water treatment methods are important advantages of ELT. Unlike conventional chemicals, the excess radicals generated in the ELT process are converted back to water and hydrogen; thus, the chemical and corrosive activity of water does not increase. Equipping research institutes with electron accelerators, developing cheaper accelerators, and granting government support for pilot projects are key conditions for introducing ELT into water treatment practice.

Bio-photoelectrochemcial system constructed with BiVO4/RGO photocathode for 2,4-dichlorophenol degradation: BiVO4/RGO optimization, degradation performance and mechanism

A single-chamber bio-photoelectrochemical system (BPES) constructed with BiVO₄/reduced graphene oxide (RGO) photocathode was proposed for 2,4-dichlorophenol (2,4-DCP) degradation under simulated solar irradiation. The BiVO₄/RGO (B/G) composites were synthesized, optimized and characterized by various techniques to analyze their physico-chemical and photocatalytic properties. Results showed that B/G (5 wt% - 9 h - 150 °C) exhibited the best photocatalytic activity for 2,4-DCP degradation, which was 1.5 times of that of BiVO₄, due to its better light absorption, faster electrons transfer, and more efficient photo-generated e^- - h⁺ separation. Reactive species trapping experiments revealed that ·OH was the main radical leading to 2,4-DCP degradation, and h⁺ also influenced 2,4-DCP removal. The 2,4-DCP (20 mg/L) removal rate and current output from the illuminated BPES were much higher than those of the unilluminated reactor (68.5 % vs. 41.8 %, 60.31 A/m³ vs. 40.07 A/m³) in 24 h, and the cathode potential was more negative, indicating that photocathode catalytic process was favorable to pollutants degradation and energy generation. Intermediates of 2,4-DCP degradation in the BPES were identified, and accordingly, possible degradation pathway and mechanism were proposed. This research advanced the development of efficient photocathode and mechanism of recalcitrant wastewater treatment in the BPES.

Treatment of petrochemical wastewater and produced water from oil and gas

Wastewater in petrochemical processes and produced water from oil and gas production remain a challenge for the industry to minimize their impact on the environment. Recent research and development of treatment technologies for petrochemical wastewater and produced water from oil and gas industries published in 2018 were summarized in this annual review. Great efforts and progresses were made in various treatment options, including membrane processes, advanced oxidation, biological systems, adsorption, coagulation, and combined processes. PRACTITIONER POINTS: Treatment technologies for petrochemical wastewater are reviewed. Research development in produced water from oil and gas industries is summarized. Reviewed technologies include traditional, advanced, and innovative processes.