Characterization and Bioactivity of Piper chaudocanum L. Extract-Doped ZnO Nanoparticles Biosynthesized by Co-Precipitation Method

Green synthesis and nanomaterials have been the current trends in biomedical materials. In this study, Piper chaudocanum L. leaf extract-doped ZnO nanoparticles (PLE-doped ZnO NPs), a novel nanomaterial, were studied including the synthesis process, and the biomedical activity was evaluated. PLE-doped ZnO NPs were synthesized by the co-precipitation method, with differences in the synthesis procedures and dosages of the extract. The X-ray diffraction, Fourier transform infrared, scanning electron microscopy, energy dispersive X-ray spectroscopy, Brunauer-Emmett-Teller, ultraviolet-visible diffuse reflectance spectroscopy, and photoluminescence spectrum analysis results showed that the biosynthesized PLE-doped ZnO NPs were pure and in a hexagonal wurtzite phase. The PLE-doped NPs were synthesized by adding the extract to the zinc acetate solution before adjusting the pH and exhibited the smallest size (ZPS50 was 22 nm), the richest in the surface organic functional groups and the best optical activity. The highest antibacterial activity against P. aeruginosa and S. aureus was observed at 100 µg/mL of ZPS50 NPs, and the inhibition zone reached 42 and 39 nm, respectively. Moreover, ZPS50 NPs showed a moderate effectiveness against KB cancer cells with an IC50 value of 43.53 ± 2.98 µg/mL. This present study's results suggested that ZPS50 NPs could be a promising nanomaterial in developing drugs for treating human epithelial carcinoma cells and infectious illnesses.

Response Methodology Optimization and Artificial Neural Network Modeling for the Removal of Sulfamethoxazole Using an Ozone-Electrocoagulation Hybrid Process

Removing antibiotics from water is critical to prevent the emergence and spread of antibiotic resistance, protect ecosystems, and maintain the effectiveness of these vital medications. The combination of ozone and electrocoagulation in wastewater treatment provides enhanced removal of contaminants, improved disinfection efficiency, and increased overall treatment effectiveness. In this work, the removal of sulfamethoxazole (SMX) from an aqueous solution using an ozone-electrocoagulation (O-EC) system was optimized and modeled. The experiments were designed according to the central composite design. The parameters, including current density, reaction time, pH, and ozone dose affecting the SMX removal efficiency of the OEC system, were optimized using a response surface methodology. The results show that the removal process was accurately predicted by the quadric model. The numerical optimization results show that the optimum conditions were a current density of 33.2 A/m², a time of 37.8 min, pH of 8.4, and an ozone dose of 0.7 g/h. Under these conditions, the removal efficiency reached 99.65%. A three-layer artificial neural network (ANN) with logsig-purelin transfer functions was used to model the removal process. The data predicted by the ANN model matched well to the experimental data. The calculation of the relative importance showed that pH was the most influential factor, followed by current density, ozone dose, and time. The kinetics of the SMX removal process followed the first-order kinetic model with a rate constant of 0.12 (min^-1). The removal mechanism involves various processes such as oxidation and reduction on the surface of electrodes, the reaction between ozone and ferrous ions, degradation of SMX molecules, formation of flocs, and adsorption of species on the flocs. The results obtained in this work indicate that the O-EC system is a potential approach for the removal of antibiotics from water.

Experimental Design, Equilibrium Modeling and Kinetic Studies on the Adsorption of Methylene Blue by Adsorbent: Activated Carbon from Durian Shell Waste

For the first time, activated carbon from a durian shell (ACDS) activated by H₂SO₄ was successfully synthesized in the present study. The fabricated ACDS has a porous surface with a specific surface area of 348.0017 m²·g^-1, average capillary volume of 0.153518 cm³·g^-1, the average pore diameter of 4.3800 nm; ash level of 55.63%; humidity of 4.74%; density of 0.83 g·cm^-3; an iodine index of 634 mg·g^-1; and an isoelectric point of 6.03. Several factors affecting Methylene Blue (MB) adsorption capacity of ACDS activated carbon was investigated by the static adsorption method, revealing that the adsorption equilibrium was achieved after 90 min. The best adsorbent pH for MB is 7 and the mass/volume ratio is equal to 2.5 g·L^-1. The MB adsorption process of ACDS activated carbon follows the Langmuir, Freundlich, Tempkin, and Elovich isotherm adsorption model, which has determined the maximum adsorption capacity for MB of ACDS as q_max = 57.47 mg·g^-1. The MB adsorption process of ACDS follows the of pseudo-second-order adsorption kinetic equation. The Weber and Morris Internal Diffusion Model, the Hameed and Daud External Diffusion Model of liquids have been studied to see if the surface phase plays any role in the adsorption process. The results of thermodynamic calculation of the adsorption process show that the adsorption process is dominated by chemical adsorption and endothermic. The obtained results provide an insight for potential applications of ACDS in the treatment of water contaminated by dyes.

Ce3+/Ce4+-Doped ZrO2/CuO Nanocomposite for Enhanced Photocatalytic Degradation of Methylene Blue under Visible Light

In recent years, photocatalysis has been used as an environmentally friendly method for the degradation of organic pigments in water. In this study, Ce³⁺/Ce⁴⁺-doped ZrO₂/CuO as a mixed semiconductor oxide was successfully prepared by a one-step hydrothermal method. The Ce³⁺/Ce⁴⁺-doped ZrO₂/CuO has shown high degradation efficiency of methylene blue (MB), and the maximum degradation percentage was observed to be 94.5% at 180 min under irradiation visible light. The photocatalytic activity increases significantly by doping Ce³⁺/Ce⁴⁺ in ZrO₂/CuO for MB degradation. Ce³⁺/Ce⁴⁺ doping is shown to reduce the (e^-/h⁺) recombination rate and improve the charge transfer, leading to enhanced photocatalytic activity of materials. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), FTIR, EDS, BET and diffuse reflectance spectroscopy (DRS).

An insight on Vietnamese bio-waste materials as activated carbon precursors for multiple applications in environmental protection

Vietnam is known as an agricultural country with a variety of agricultural crops. In addition to agricultural by-products, bio-waste is the by-product from livestock waste, forestry, industry, and daily life. They affect the soil, water, and air environment by self-degradation processes in the environment. Therefore, researchers have come up with ideas for the usage of the by-products to decrease the amount of waste and minimize the environmental effects. In Vietnam, the by-products were used by researchers to produce bio-ethanol, fertilizers, composites, and activated carbon (AC). AC is one of the materials used to rapidly reduce the number of agricultural by-products by researchers. The synthesis process is optimized for the highest yield, while the physicochemical properties are also clearly analyzed through the X-ray diffraction, Fourier transform infrared, and Bacterial endotoxin testing assays. The average recorded specific surface area was about 300 m2 g−1. The functional groups and surface structure showed that the material has an amorphous structure with –OH, –CH, –CC, –C═C, –C═O groups. The AC from agricultural waste had been studied and applied to treat pollutants present in water.

Photocatalytic degradation of Rhodamine B in aqueous phase by bimetallic metal-organic framework M/Fe-MOF (M = Co, Cu, and Mg)

Bimetallic metal-organic frameworks (MOFs) exhibit outstanding performance in a wide range of applications, including gas catalysis, adsorption, and luminescence sensor. The structure and properties of materials can be designed based on the variation of different metal ions, so this MOFs material system has unique properties. In this study, M/Fe-MOF bimetallic materials (M = Co, Cu, and Mg) were synthesized by solvothermal method and evaluated for photocatalytic activity in the degradation reaction of rhodamine B (RhB) organic pigments. The as-synthesized materials were characterized by using several physicochemical methods such as X-ray diffraction, fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-Vis), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), and UV-Vis diffuse reflectance spectra. The results show that the Co/Fe-MOF, Cu/Fe-MOF, and Mg/MOF materials have uniform grain grade, high crystallinity, with the surface area of 26.1, 25.9, and 25.9 m2/g, respectively. When modified with Co, Cu, and Mg, the crystal structure of Fe-MOF materials was unchanged, and all metal ions are inserted inside the structure of the material, as well as replacing Fe ions in the lattice crystals. At the same time, the modification also increases the light absorption in the visible light region and gives a high photocatalytic degradation of RhB organic pigments under visible light in the range of 85–92%.

Comprehensive review on synthesis, physicochemical properties, and application of activated carbon from the Arecaceae plants for enhanced wastewater treatment

Arecaceae presents one of the plant families distributed mainly in the equatorial and subequatorial regions. Arecaceae are widely applied in many fields such as food, cosmetics, fuel, and chemical industries. However, a large amount of agricultural waste from the Arecaceae trees has been released into the environment. The objective of this report is to gain more insights into the potentials and applications of activated carbon (AC) from the Arecaceae trees in wastewater treatment, in which, the ability to handle organic pigments, metals, and antibiotics is focused. The physical properties and processability of AC are statistically evaluated. With a uniform structure, large specific surface area, processing ability according to Langmuir and pseudo-second-order models, we showed that ACs from Arecaceae trees are promising materials for water treatment applications. This is the basis for the development and reduction of by-products that affect the environment.

Color and composition of beauty products formulated with lemongrass essential oil: Cosmetics formulation with lemongrass essential oil

Diversification of products that are derived from essential oils carries important implications in reducing agricultural waste and promoting the medicinal materials industry. In this study, we formulated a shampoo and a body wash product incorporated with lemongrass (Cymbopogon citratus) essential oils (LEOs) and evaluated their color stability and the LEO compositional change. We first determined the color change and chemical composition of bare LEO under different storage conditions. Afterward, the washing product base was formulated, and its formulation process was optimized to minimize the color change by varying a wide range of parameters including pH, the inclusion of preservatives and antioxidants, LEO/antioxidant ratio, and emulsification temperature. The base product was then used in body wash and shampoo formulation following our previously reported procedure. The results indicated that direct incorporation of the LEO into the cosmetic products resulted in better color stability and citral retention in comparison with emulsion formation. In addition, shampoo and body wash products showed no detectible presence of compounds resulting from citral decomposition such as 3,7-dimethyl-1,3,6-octatriene, p-mentha-1,5-dien-8-ol, and p-cymene-8-ol. The current findings are expected to aid in diversifying LEO-derived commodities and justifying scalability of the cosmetics production process with a focus on the incorporation of naturally derived ingredients.