Abstract This study develops a plastic cycle toward circular economy practice in Vietnam. First, we analyze inter-relationships between economic sectors and environmental issues concerning plastic waste in 2018. The research method integrates interdisciplinary balance with life cycle inventory, in which input–output (IO) table is both an econometric tool and original database to determine plastic IO between industries. As a result, over 60% of plastics after use was recycled for the production process (called recycled plastics) and nearly 40% of plastics after-use left the process (called disposed plastics). Within the recycled plastics, there was 10–15% of informal recycling collection from trade villages; within the disposed plastics, there was 13–18% unable to be collected and uncontrollably disposed to the environment. Then, we construct the plastic cycle, in which all the imported/domestic flows, single/multiple uses, and recycle/disposal flows are represented in proportional dimensions. This overall yet quantitative picture is an important data-driven basis for proposing plastic waste management solutions toward circular economy practice. As analyzed, the most challenge for waste management in Vietnam is to control single-use products (occupied 15.96% of total plastics) and indiscriminate waste in the environment (occupied 20.36% of total plastics). The case study for polyethylene terephthalate shows the need for expanding producer’s responsibilities to improve plastic recovery efficiency.

Abstract Bacterial cellulose (BC) produced from coconut water, commonly known as nata de coco, is a biopolymer with enormous properties. Compared to plant cellulose, BC has better mechanical strength and a greater degree of polymerization. BC’s high purity and high porosity make it a suitable candidate for the embedding and dispersion template for silver nanoparticles (AgNPs). This study investigated a facile and scalable method of making BC from coconut water and impregnated them with AgNO3 solution to produce AgNPs templated BC. The resulting materials were characterized by Fourier transform infra-Red (FTIR), scanning electron microscope (SEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD). The thermal stability was also investigated by thermogravimetric analysis (TGA). The antibacterial activity of AgNPs templated BC was challenged in cultures of gram-positive bacteria Staphylococcus aureus and gram-negative bacteria Escherichia coli and showed an inhibition zone of growth in agar media. This study proves that the resulting AgNPs templated BC sheets are potential materials for antibacterial and industrial application that are low cost and easy to produce.

Abstract Renewable biomass resources have become increasingly attractive in recent years. In this study, the pyrolysis of waste navel orange peels was carried out with different metal oxides (Cu2O, CaO, V2O5, Fe2O3, and ZnO) in a tube furnace to obtain high-quality bio-oil, from which high-value chemicals such as 3-furaldehyde could be well recovered to enhance the economic value of waste navel orange peels. The effects of different metal oxides on bio-oil were analyzed by GC/MS. The results showed that Cu2O and Fe2O3, as catalysts for slow pyrolysis, promoted the production of 3-furaldehyde compounds at a scale of approximately 5.69 and 4.82 times higher than that of pyrolysis without the addition of metal oxides, respectively. High-value chemicals such as 3-furaldehyde obtained from bio-oil can enhance the economic value of waste navel orange peels for full recovery and reuse.

Abstract A cerium/silver/zinc oxide (Ce/Ag/ZnO) inorganic nanocomposite was synthesized through a homogeneous precipitation method. The characterization and photocatalysis procedures were carried out by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflection spectroscopy, and photocatalytic performance. The characteristic absorption peak of ZnO was near 432 cm−1, no absorption was observed peak near 1,083 cm−1 for CeO2 and ZnO, the absorption peak near 721 cm−1 was generated by the vibration of CeO2, and the absorption peak had an obvious blue shift. The XRD results showed a strong interfacial interaction among Ag, CeO2 and ZnO to form a core–shell structure. The SEM image showed that the Ce/Ag/ZnO samples are approximately 25 nm. The XPS spectra showed that the Ce/Ag/ZnO nanocomposite powders were successfully prepared. The UV-Vis diffuse reflection spectra showed that the Ce/Ag/ZnO nanocomposites reduced the band gap and increased the ability of visible light response. The addition of rare earth Ce could inhibit the recombination of ZnO photoelectron pairs and improve the photocatalytic effect. Therefore, Ce/Ag/ZnO exhibited good characteristics of nanocomposite materials and good photocatalytic ability.

Metal oxide nanoparticles (NPs) have found a variety of applications in numerous industrial, medical, and environmental fields s, attributable to recent advances in the nanotechnology field. Titanium dioxide nanoparticles (TiO 2 -NPs) have gained importance as metal oxide NPs due to their potential in various fields, particularly nanomedicine and other biomedicine fields. Several studies have confirmed that NPs produced via the biosynthesis route using natural resources have significant advantages such as fewer toxic contaminants, less subsequent complex chemical synthesis, environmental friendliness, cost-effectiveness, and stability when compared to NPs produced by conventional methods, and its production with controlled shapes and sizes. Therefore, considerable effort is being expended to implement biological synthesis methods with these proven advantages. TiO 2 -NPs can be made using a variety of biological, chemical, and physical methods. Physicochemical methods are costly, emit high levels of toxic chemicals into the atmosphere, and consume a lot of energy. On the other hand, the biological approach is an environmentally safe, cost-effective, dependable, convenient, and easy way to synthesize TiO 2 -NPs. In this review, the bio-mediated synthesis, as well as various biomedical applications of TiO 2 -NPs, were discussed.

Abstract Plant-mediated silver nanoparticles are unique and are considered one of the best nanomaterials used in cancer research. We report a low-cost, eco-friendly process of green synthesis of AgNPs from Commiphora gileadensis stem extracts and evaluated their anticancer potential against colon cancer cell lines HCT-116, HT 29, and SW620. Anticancer activities were performed by an MTT assay and gene expression levels of four genes CHEK1, CHEK2, ATR, and ATM by the real-time polymerase chain reaction. Particles were initially confirmed by UV-visible spectroscopy. The morphology and stability of the particles were examined through TEM, zeta potential, and zeta sizer. GC-MS and FTIR were performed to examine the functional groups. The absorption peak was recorded at 430 nm; the average size recorded by TEM images was 13 nm, while the zeta potential and zeta sizer study showed aggregation in nanoparticles. Compared to C. gileadensis extracts, some of the FT-IR spectrum peaks were sight shifted with some new peaks in C. gileadensis AgNPs. C. gileadensis AgNPs were more toxic against HT29 followed by HTC116 and SW620. Expression levels of most of the genes in HCT116 and HT29 were increased by treatment whereas the gene expression level was least affected in SW620. C. gileadensis AgNPs have anticancer potential and need to be explored in cancer research.

Abstract Generally, adding a certain amount of an additive to pulverized coal can promote its combustion performance. In this paper, the effect of CaO on the combustion characteristics and kinetic behavior of semi-coke was studied by thermogravimetric (TG) analysis. The results show that adding proper amount of CaO can reduce the ignition temperature of semi-coke and increase the combustion rate of semi-coke; with the increase in CaO content, the combustion rate of semi-coke increases first and then decreases, and the results of TG analysis showed that optimal addition amount of CaO is 2 wt%. The apparent activation energy of CaO with different addition amounts of CaO was calculated by Coats–Redfern integration method. The apparent activation energy of semi-coke in the combustion reaction increases first and then decreases with the increase in CaO addition. The apparent activation energies of different samples at different conversion rates were calculated by Flynn–Wall–Ozawa integral method. It was found that the apparent activation energies of semi-coke during combustion reaction decreased with the increase in conversion.

In this study, the synthesized CuCo-zeolitic imidazolate framework (ZIF) catalyst was used to degrade methyl orange (MO) and methylene blue (MB) in water via a novel Fenton-like catalytic reaction. Effects of catalyst dosage, H 2 O 2 concentration, initial concentration of the contaminants, and reaction time were evaluated. The results showed that MO and MB decomposition efficiencies were highly influenced by CuCo-ZIF concentration. The presence of H 2 O 2 accelerated the degradation reaction of both MO and MB. Although it took 100 min to complete the removal of MB, it was 60 min for MO. At concentrations of MO and MB lower than 40 mg·L −1 , the catalyst showed an almost complete degradation. The CuCo-ZIF catalyst presented a good recyclability with more than 90% removal of MO and MB after four times and five times reuse, respectively. These results demonstrated that MO and MB were efficiently degraded by a Fenton-like catalyst of CuCo-ZIFs and its potential in industrial wastewater treatment. Graphical abstract

Abstract The emergence of drug-resistant bacteria and the lack of effective antimicrobial agents have posed a threat to public safety, so a new efficient strategy is needed to deal with the increasing severity of bacteria. Herein, a substitute antibacterial agent with high stability and biocompatibility was synthesized by incorporating lysine hydrochloride and copper sulfate pentahydrate following the liquid-phase synthesis method. The composition and structure of the Cu(ii) complex (Lys–Cu) were characterized by performing ultraviolet-visible spectrophotometry, Fourier-transform infrared spectroscopy, X-ray diffractometry (XRD), thermogravimetric analysis-differential scanning calorimetry, and single-crystal XRD. The crystal structure of Lys–Cu belongs to a monoclinic system, space group P21, with cell parameters of a = 5.14350(10), b = 16.8308(2), c = 11.4915(2) Å, Z = 2, and D = 1.548 g·cm−3. Bacteriostatic tests were carried out on Escherichia coli and Staphylococcus aureus. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of Lys–Cu against S. aureus were 0.3125 and 0.9250 mg·mL−1, respectively. The MIC and MBC values of Lys–Cu against bacterial strain E. coli were 0.4685 and 0.9250 mg·mL−1, respectively.

Abstract Nanoparticles synthesized from plants are being explored for cancer treatment therapies all over the world. This study reported the eco-friendly and low-cost method for the green synthesis of silver nanoparticles (AgNPs) from Adansonia digitata fruit as a reducing and capping agent. The anti-cancer potential of synthesized particles was explored against HTC116 and SW480 colon cancer cell lines. Prepared AgNPs were characterized by ultraviolet-visible spectroscopy, zeta potential, transmission electronic microscopy, scanning electronic microscopy, Fourier transform infrared, and energy-dispersive spectrum. The cytotoxicity was determined with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and expression levels of four genes (CTNNB1, APC, LRP5, and LRP6) were checked by reverse transcription polymerase chain reaction. The sharp peak of surface plasmon resonance at 400 nm confirms the formation of AgNPs. Dynamic light scattering showed average sizes of 16.34 nm with a polydispersity index of 0.193. A. digitata AgNPs were spherical with slight aggregated. AgNPs were more cytotoxic than A. digitata extract and decrease the expression of CTNNB1 and LRP6 genes while LRP5 gene expression was increased in both cell lines. APC gene expression was decreased in SW480 but increased in HTC116 with treatment. Overall, this study suggested that AgNPs synthesized by A. digitata fruit extract can be an attractive candidate for anticancer applications.

Cefonicid is a common second-generation cephalosporin, and the 7-amino-3-[sulphomethyl-1- H -tetrazol-5-yl-thiomethyl]-3-cephem-4-carboxylate monosodium salt is a key synthetic intermediate in its preparation. Despite the considerable international demand for this antibiotic, its preparation is hampered by low synthetic yield, long reaction time, and time-consuming industrial filtration over charcoal after the purification step. In the context of the industrial production of pharmaceutical intermediates, in which the balance between streamlining and enhancing productivity is necessary in order to compete in the global active pharmaceutical ingredients (API) market, we have investigated an efficient and practical procedure for the synthesis of a key cefonicid intermediate that features a telescopic route whose synthetic steps are all performed at room temperature; from the displacement of the acetoxy group with boron trifluoride to crystallization without treatment with charcoal. In other words, a simpler, scalable, cost-effective and energy-saving protocol is herein reported as a means of moving towards commercial manufacturing. The optimization of the process parameters and the industrial-scale impact assessment should pave the way for industrialization.

Abstract To change the optical properties and improve the antibacterial performances of carbon quantum dots (CQDs) and Ag NPs, mesoporous SiO2 spheres were combined with them to form the composites. In this paper, CQDs with a uniform size of about 3.74 nm were synthesized using glucose as carbon source. Then, CQDs/mesoporous SiO2/Ag NPs composites were obtained in situ under UV light irradiating by using mesoporous SiO2 and Ag NO3 as the carrier and silver resource, respectively. The diameter of CQDs/mesoporous SiO2/Ag NPs particles was in the range of 200–250 nm. With the increase in irradiating time, the red-shift in the UV-Vis spectrum for as-prepared CQDs/mesoporous SiO2/Ag NPs composites was found, and the adsorption peak was widened. In addition, the composites showed a high antibacterial activity against Staphylococcus aureus and Escherichia coli via disc diffusion method. These results indicated that inhibition circles for Ag NPs/mesoporous SiO2/CQDs and mesoporous SiO2/Ag NPs were similar in diameter. Furthermore, the two composites had a better bactericidal performance compared with other particles. Therefore, as-prepared CQDs/mesoporous SiO2/Ag NPs composites in this paper have great potential applications for fluorescent materials and antibacterial materials.

Traditional Chinese herbs have attracted extensive attention due to their good efficacy, low toxicity, and minor side effects. However, some active ingredient extracts are relatively sensitive to external influence and liable to lose their effectiveness. Different from the traditional and complex encapsulation methods, one can easily prepare drug-loaded microcapsules to improve their bioavailability using the new encapsulation technology. In this work, we used the sonochemical method to prepare bovine serum albumin (BSA)/astragalus membranaceus oil (AM) microcapsules. The technology was simpler, greener, and more efficient. Thereinto, BSA and AM oil were used as the shell material and the core material, respectively. The effects of ultrasonic amplitude, ultrasonic mode, and ultrasonic time on synthetic reactions were studied. The morphology and size of the BSA/AM microcapsules were investigated using transmission electron microscopy, scanning electron microscopy, and dynamic light scattering (DLS). The loading efficiency and drug release behavior were determined using thermogravimetric analysis (TGA) and ultraviolet (UV) spectroscopy, respectively. The best ultrasonic synthesis conditions were obtained by the above analysis, with an ultrasound amplitude of 30%, ultrasound mode of the pulse mode of 2 s, ultrasound time of 4 min. The DLS results show that the microcapsule size is 484.4 nm and the polydispersity index is small. The TGA results show that the drug loading efficiency is about 77%, and the hemolysis tests show that the BSA/AM microcapsules have no cytotoxicity at lower concentrations (lower than 50 μg·mL −1 ).

Abstract Recent studies have shown that green synthesis of silver nanoparticles (AgNPs) and their application in the control of phytopathogenic fungi is a burgeoning field. Sisymbrium irio (Si) (London rocket) is a well-known weed that grows abundantly in Saudi Arabia from February to May. The present study is concerned with the rapid synthesis of silver nanoparticles from the aqueous seed extract of Si) in the presence of sunlight. The biosynthesized Si-AgNPs were characterized using UV-Visible spectroscopy (UV-Vis), energy dispersive X-ray (EDX) microanalysis, dynamic light scattering analysis (DLS), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy analysis (FTIR). The UV-Vis spectrum revealed a prominent surface plasmon resonance (SPR) absorption band (∼439 nm) characteristic of AgNPs. As revealed by TEM analysis, the Si-AgNPs were predominantly spheroidal in shape and measured between 4 and 51 nm, while the Z average of nanoparticles was 94.81 nm as revealed by the DLS spectrum. The FTIR spectrum displayed peaks related to important functional groups (amines, phenols, carboxylic acids, flavonoids, aromatic compounds, and esters) that aid in the reduction, encapsulation, and stability of AgNPs. The Si-AgNPs were further investigated against a panel of potent fungal phytopathogens that included Alternaria alternata, A. brassicae, Fusarium solani, F. oxysporum, and Trichoderma harzianum. The cytotoxic activity of the biosynthesized nanoparticles against human cervical cancer cell lines (HeLa) was also tested. Si-AgNPs at 80 µg·mL−1 demonstrated a marked reduction in mycelial growth and spore germination. Similarly, Si-AgNPs exhibited dose-dependent cytotoxic activity against the HeLa cell line, with an IC50 value of 21.83 ± 0.76 µg·mL−1. The results of the present study demonstrate the robust cytotoxic and antifungal activities of Si-AgNPs. Based on the findings, Si-AgNPs can be exploited to design formulations that can effectively act as anticancer agents, controlling the proliferation of cancer cells while also combating fungal phytopathogens. However, future research to understand their toxicity mechanisms is needed.

Abstract Hydrogels are promising drug delivery systems attributable to their unique characteristics such as high hydrophilicity, controllability, biocompatibility, and facile production routines. The aim of this research was the preparation of sodium alginate/acrylic acid (AAc) composite hydrogels conjugated to silver nanoparticles to deliver the cephalexin as a model antibiotic compound. The reduction of silver ions into silver nanoparticles as well as the stabilization of created nanoparticles ensued simultaneously with hydrogel backbone formulation during microwave irradiation and monomer cross-linking processes. The impact of AAc and silver ion concentrations and the radiation time of microwave were then investigated on the main characteristics of hydrogels. The results indicated that the hydrogels’ characteristics could be significantly predicted by studying all independent parameters through various second-order polynomial models. The multiple optimization analysis suggested that the prepared hydrogels using 7.8 g AAc and 1.5 g silver nitrate and 1 min microwave radiation could give the best hydrogels with the highest swelling degree, gel fraction, cephalexin absorption, and antibacterial activity. The morphology and either absorption or release kinetics of cephalexin by the optimum prepared hydrogels were also investigated. No significant differences between the experimental and predicted data confirmed the suitability of the suggested models.

Abstract In this study, we prepared and characterized ceramsite-supported nanoscale zero-valent iron (nZVI). Malachite green (MG) dye removal from aqueous solutions using a fixed-bed reactor packed with the above composite material was investigated. This research was carried out according to the prophase study of the preparation and characterization of ceramsite material for water treatment using sintering method from solid wastes. The results indicated that ceramsite could be loaded with nZVI, mainly because of its magnetic property. With the decrease in the initial concentration and influent flow rate or the increase in the reaction temperature, the breakthrough curve became less steep. Meanwhile, the breakthrough and saturation points gradually shifted rightward. When the initial concentration was 10 mg·L−1, the reaction temperature was 25°C, and the influent flow rate was 5 mL·min−1, the breakthrough curve presented an irregular “S” shape, the breakthrough and saturation times were 230 and 515 h, respectively. The characterization of MG dye-containing wastewater treatment using ceramsite-supported nZVI in a fixed-bed reactor by employing the Yoon-Nelson kinetic model was superior to those using the Thomas and Adams-Bohart kinetic models, with R 2 > 0.96.

Rare earth metal cerium-doped titania nanoparticles (titanium dioxide [TiO 2 ]) were produced utilizing a low-cost and straightforward sol–gel technique, and its enhanced photodynamic anticancer activity was tested on Y79 retinoblastoma cancer cells. The structural, optical, morphological, anticancer activity, and cytotoxicity of pure and cerium-doped TiO 2 (Ce-doped TiO 2 ) were investigated. In X-ray diffraction (XRD) measurements, apparent doping of cerium in TiO 2 was detected, with reported anatase patterns shifting toward a lower angle in the anatase structure. Raman spectra verify the presence of cerium doping in TiO 2 by revealing greater wave number shifting. The scanning electron microscope (SEM) and transmission electron microscope (TEM) analysis showed that the synthesized TiO 2 and Ce-doped TiO 2 nearly spherical. TiO 2 and Ce-doped TiO 2 were studied for their photodynamic anticancer activities, and the results suggest that cerium doping in TiO 2 improves anticancer activity.

Abstract Currently, the prime focus in agricultural research is on sustainability and protection of agricultural produce with minimal use of synthetic fungicides. In the present study, silver nanoparticles (AgNPs) were synthesized using fresh leaves of Mentha pulegium (M.p) through a simple, easy, and economical method. The formation of M.p-AgNPs was ascertained with UV-visible spectroscopy that gave a surface plasmon resonance peak at 430 nm. Further, M.p-AgNPs were characterized by energy dispersive X-Ray analysis (EDX), transmission electron microscopy (TEM), dynamic light scattering, and Fourier-transform infrared (FTIR) spectroscopy. The DLS spectrum and TEM microphotographs showed that the M.p-AgNPs were small in size, measuring between 4 and 60 nm. Significant hyphal growth inhibition of some selected fungal phytopathogens was achieved after exposing them to various concentrations of M.p-AgNPs. The M.p-AgNPs (40 µg·mL−1) suppressed the fungal mycelial growth of all the test isolates significantly. When compared to the control, Fusarium solani (63% inhibition) and Alternaria alternata (61% inhibition) showed the highest inhibition. Likewise, spore germination was inhibited in a potent manner. Hence, based on the findings of the present study, M.p-AgNPs can be used to create a low cost, nontoxic, eco-friendly fungicide to control the growth and proliferation of some fungal phytopathogens in the agricultural sector.

A kinetic model for the reactions between the low-fluoride slag CaF 2 –CaO–Al 2 O 3 –MgO–Li 2 O–TiO 2 and Incoloy 825 alloy was proposed based on the two-film theory. The applicability of the model was verified to predict the variation of components in the slag–metal reaction process. The results show that the controlling step of the reaction 4[Al] + 3(TiO 2 ) = 3[Ti] + 2(Al 2 O 3 ) is the mass transfer of Al and Ti in the liquid alloy and the controlling step of the reactions 4[Al] + 3(SiO 2 ) = 3[Si] + 2(Al 2 O 3 ) and [Si] + (TiO 2 ) = [Ti] + (SiO 2 ) is the mass transfer of SiO 2 in the molten slag. With increasing TiO 2 content in the slag from 3.57% to 11.27%, the Al content in the alloy decreased whereas the Ti content increased gradually. The Si content continued to decrease during the slag–metal reaction. Soluble oxygen in the alloy reacts with Al, Ti, and Si, resulting in a decrease of the oxygen content in the alloy. The variations of TiO 2 content were in good agreement with the calculated results by the kinetic model whereas the measured results of Al 2 O 3 and SiO 2 in the slag were lower than the calculated results, which is mainly due to the volatilization of fluoride.

Green-synthesized nanoparticles have a tremendous antimicrobial potential to be used as an alternative to hazardous fungicides. In this study, the green synthesis of silver nanoparticles (AgNPs) was performed by using Moringa oleifera leaf extract as a reducing and stabilizing agent. The synthesized AgNPs were subjected to different characterization techniques. UV-visible spectroscopy confirmed the surface plasmon resonance band in the range of 400–450 nm, and zeta analysis revealed that the synthesized AgNPs ranged 4–30 nm in size. Scanning electron microscopy depicted tiny fused rectangular segments and the crystalline nature of the synthesized AgNPs was confirmed using X-ray diffraction. Energy dispersive X-ray (EDX) detector confirmed the presence of metallic silver ions. Fourier-transform infrared analysis revealed the presence of phenols as main reducing agents in the plant extract. Foliar application of different concentrations (25, 50, 75, and 100 ppm) of AgNPs was applied on wheat plants inoculated with Puccinia striiformis to assess the disease incidence against stripe rust disease. AgNPs at a conc. of 75 ppm were found to be more effective against wheat stripe rust disease. Furthermore, the application of AgNPs enhanced morpho-physiological attributes and reduced nonenzymatic compounds and antioxidant enzymes in wheat. The present study highlights the potential role of the green-synthesized AgNPs as a biological control of yellow rust disease.