In this study, nanocrystalline ZnNd_xFe_2−xO₄ ferrites with x = 0.0, 0.01, 0.03 and 0.05 were fabricated and used as a catalyst for dye removal potential. The effect of Nd³⁺ ions substitution on the structural, optical and photo-Fenton activity of ZnNd_xFe_2−xO₄ has been investigated. The addition of Nd³⁺ ions caused a decrease in the grain size of ferrites, the reduction of the optical bandgap energies and thus could be well exploited for the catalytic study. The photocatalytic activity of the ferrite samples was evaluated by the degradation of Rhodamine B (RhB) in the presence of H₂O₂ under visible light radiation. The results indicated that the ZnNd_xFe_2−xO₄ samples exhibited higher removal efficiencies than the pure ZnFe₂O₄ ferrites. The highest degradation efficiency was 98.00%, attained after 210 min using the ZnNd_0.03Fe_1.97O₄ sample. The enhanced photocatalytic activity of the ZnFe₂O₄ doped with Nd³⁺ is explained due to the efficient separation mechanism of photoinduced electron and holes. The effect of various factors (H₂O₂ oxidant concentration and catalyst loading) on the degradation of RhB dye was clarified.

Fe-Cu materials were synthesized using the chemical plating method from Fe powder and CuSO₄ 5% solution and then characterized for surface morphology, composition and structure by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The as-synthesized Fe-Cu material was used for removal of phenol from aqueous solution by internal microelectrolysis. The internal electrolysis-induced phenol decomposition was then studied with respect to various parameters such as pH, time, Fe-Cu material weight, phenol concentration and shaking speed. The optimal phenol decomposition (92.7%) was achieved under the conditions of (1) a pH value of phenol solution of 3, (2) 12 h of shaking at the speed of 200 rpm, (3) Fe-Cu material weight of 10 g/L, (4) initial phenol concentration of 100.98 mg/L and (5) at room temperature (25 ± 0.5 °C). The degradation of phenol using Fe-Cu materials obeyed the second-order apparent kinetics equation with a reaction rate constant of k of 0.009 h⁻¹L mg⁻¹. The optimal process was then tested against real coking wastewater samples, resulting in treated wastewater with favorable water indicators. Current findings justify the use of Fe-Cu materials in practical internal electrolysis processes.

Untreated coking effluent presents a great challenge for sustainable development of the steel industry and environment preservation. In this study, an internal micro-electrolysis method using Fe/C materials was employed for pretreatment of real coking wastewater with high mass concentration. The Fe/C materials were prepared by Fe powder and graphite powder; and the characteristics of surface morphology, structure, composition of the synthesized materials were examined by Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Energy Dispersive X-ray Spectroscopy (EDS). The effects of factors namely dosage of Fe/C material, treatment time, initial pH and temperature were investigated via chemical oxygen demand (COD) and phenol removal efficiencies. Optimal treatment efficiency was attained at pH of 4, Fe/C dosage of 40 g/L, treatment time of 360 minutes and temperature of 25°C. After the internal electrolysis process, the values of COD, BOD5, and phenol of the wastewater were 6500, 4850 and 0.1 mg/L, respectively.

Elsholtzia winitiana var. dongvanensis Phuong is a plant contains an essential oil characterized by an important chemical transformation. Essential oils were isolated from Elsholtzia winitiana var. dongvanensis Phuong flowers and aerial parts by hydrodistillation and analyzed for chemical constituents by GC-MS. Twenty-two components accounting for 99.99% of the total oil of flowers and twenty-three components accounting for 98.72 % of the total oil of aerial parts were identified. The composition of the essential oil contains aldehyde, aromatic ketone, monoterpenoid and secquiterpenoid. Major components found in two essential oil samples were andehyde, terpenoid, ketone benzaldehyde, germacrene D, E-caryphyllene and caryophyllene oxide. Moreover, essential oil sample isolated from flowers and aerial parts of E. winitiana var. dongvannensis was dominated by the high content of rosefuran (75.67%) and rosefuran epoxide (71.33%), respectively.

The study aimed to determine the polyphenols, total flavonoids, and antioxidant activities of extracts from Lamiaceae: Perilla frutescens L. and Clerodendrum paniculatum L. Both of them are belonging to the Lamiaceae family, which is distributed evenly in Africa, Asia, and America. In addition to being used as a spice in daily food, these two plants also have many other great uses such as treating runny nose, fever, anti-inflammatory, and diarrhea. The antioxidant activity of these plants is also appreciated in many studies around the world. In this research, the method of soaking the plants with the solvent was distilled water. For hot extraction, ethanol was used. Total polyphenol content was determined by Folin-Ciocalteu method, flavonoid content was determined by Aluminum chloride colorietric method and antioxidant activity was evaluated in vitro through DPPH free radical scavenging method (1,1-Diphenyl-2-picryl hydrazyl) and ABTS (2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)). The results show that Clerodendrum paniculatum has polyphenol content (40.42 mg GAE/g and 33.35 mg GAE/g) and flavonoids (28.43 mg GAE/g and 37.12 mg QE/g) were highest in water and ethanol solvents. The best antioxidant activity was determined in the extract of Clerodendrum paniculatum by both DPPH and ABTS methods. The IC50 values according to DPPH method of ethanol and water solvents were 280.06 µg/mL and 588.17 µg/mL and ABTS method were 51.70 µg/mL and 72.09 µg/ mL, respectively.

Achyranthes aspera Linn and Amaranthus spinosus Linn are herbaceous plants with high pharmacological potential because they contain many antioxidant activities such as polyphenols and flavonoids. This study aimed at preliminary evaluation of bioactive compounds with antioxidant capacity from Amaranthaceae family. Prepared ethanol and water extracts from stems and leaves and then investigated the antioxidant capacity by DPPH and ABTS free radical scavenging methods. The results show that the ethanol and water extracts from the organs of Achyranthes aspera and Amaranthus spinosus have antioxidant activity, which is the basis for scientists to use active substances extracted from those plants in pharmacology and human life, contributing to improving the use-value of Amaranthaceae. These results are a premise for further studies related to the acquisition of biologically active compounds.