The main characteristic features of nickel–copper-catalyzed azide–alkyne click (Ni-CuAAC) reactions for production of 1,2,3-triazoles are regioselectivity and the reaction proceeding under mild conditions. The use of copper salts as catalysts often leads to challenges like contamination of the prepared triazoles. NiO/Cu2O nanocomposites (NCs) were utilized in Ni-CuAAC reactions as heterogeneous nanocatalysts to achieve the production of some 1,4-disubstituted 1,2,3-triazoles in high chemical yields under microwave irradiation.
RESULTS
The preparation of NiO/Cu2O NCs was performed through the coprecipitation of NiO nanoparticles on Cu2O surface. The prepared catalyst was used for catalyzing a reaction between benzoyl azides and phenylacetylene under optimized reaction conditions. The NiO/Cu2O NCs exhibited high catalytic activity compared to Cu2O nanoparticles. In addition, by utilizing ethanol–water as the solvent system under microwave irradiation, higher yields and efficient product separation were observed.
Arailym Kamal, Yerkanat N Kanafin, Aliya Satayeva, Jong Kim, Stavros G Poulopoulos, Elizabeth Arkhangelsky
BACKGROUND
Medical substances are utilized around the world, and their accumulation in nature is a global concern. This work aimed to identify three priority pharmaceuticals discharged into the domestic sewage stream of Astana city (Kazakhstan). Samples of municipal wastewater were taken before and after the wastewater treatment plant (WWTP) over a period of 13 months. The performed experiments demonstrated that there are seasonal variations in the priority pharmaceuticals – carbamazepine (CBZ), sulfamethoxazole (SMX) and aspirin (ASP) – identified in the wastewaters.
RESULTS
The non-conventional WWTP of Astana city, which includes a sequence of treatment processes, showed 2–100% removal of these compounds with the following influent concentrations from the entering stream: 12.5–185.6 ppb (μg L−1) for CBZ, 2.6–51.2 ppb for SMX and 1.9–199.8 ppb for ASP. Laboratory-scale experiments revealed that the application of the membrane separation technique, i.e. ultrafiltration, is able to provide improved removal of these pharmaceuticals. The removal of ASP, CBZ and SMX by phase inversion polyethersulfone and track etch (TE) polycarbonate membranes was investigated. Filtration with TE membrane demonstrated 39–97% removal of the primary pharmaceuticals from the wastewater.
Shuaipeng Li, Neng Guo, Dongdong Zhu, Dazhan Jiang, Zhenting Chen, Shengwen Chen, Zhiguo Sun, Jifen Wang
BACKGROUND
Magnesium oxide (MgO) is favored for solid-state carbon dioxide (CO2) capture due to its high theoretical adsorption capacity, abundant reserves, low cost, and environmental friendliness. However, its practical application in industry is hindered by low CO2 adsorption capacity under moderate operating conditions. In this work, MgO was modified by a deposition method using LiNO3, NaNO3, KNO3, Na2CO3 and K2CO3 as additives.
RESULTS
The study determines optimal ratios within the [(Li, Na, K)x − (Na, K)]y/MgO system, specifically identifying x = 0.5 and y = 0.15 as most effective. At 275 °C under pure CO2 conditions, the adsorption capacity peaks at 0.631 g CO2 g−1 adsorbent. Effective regeneration of the adsorbent occurs at 400 °C under 100% N2 for 15 min. Under Integrated Gasification Combined Cycle (IGCC) conditions, the adsorption capacity stabilizes at 0.462 g g−1 after 20 cycles, representing a 25% decrease from initial capacity.
A series of Pt@NZSM–5 and Pt/NZSM–5 nanosheets having different Si/Al ratios were prepared via an in situ synthesis and impregnation method, respectively, using C22H45–N+(CH3)2–C6H12–N+(CH3)2–C6H13 (C22–6–6) as the template agent. The oleic acid decarboxylation reaction was carried out using these materials under CO2 atmosphere and the oleic acid cracking mechanism was inferred from the product distribution of the C8-C17 alkanes.
RESULTS
The Pt@NZSM–5 and Pt/NZSM–5 was found to comprise thinner nanosheets and exhibited strong metal–substrate interactions. Pt@NZSM–5 nanosheets with a Si/Al molar ratio of 100 had thicknesses of only 8–9 nm along with a mesopore/micropore capacity ratio of 2.7, an acid content of 11 cm3/g STP and a high Pt0/PtOx ratio.
Mohamad Razif Mohd Ramli, Noor Fazliani Shoparwe, Mohd Azmier Ahmad, Mohamad Firdaus Mohamad Yusop
BACKGROUND
Acetaminophen, also known as paracetamol, has been notably detected in aquatic environments, including wastewater, surface water and drinking water, causing significant concern within the scientific and environmental research communities. This study focuses on two main objectives: (i) optimizing corn cob-based activated carbon (CCAC) through response surface methodology for the adsorption of acetaminophen and (ii) simulating the acetaminophen adsorption process using the polymath mass transfer (PMT) model.
RESULTS
The optimized CCAC was prepared via physiochemical activation under microwave radiation (265 W power) for 6 min, with a KOH impregnation ratio of 0.50 g g−1. This process resulted in a high Brunauer–Emmett–Teller surface area of 976.29 m2 g−1, accompanied by a corresponding pore volume of 0.39 cm3 g−1 and a pore diameter of 2.38 nm. The adsorption study, employing differential initial concentrations (ranging from 5 to 30 mg L−1) of acetaminophen, revealed a substantial adsorption capacity of 22.43 mg g−1 (74.77%) at 30 °C and 20.74 mg g−1 (69.13%) at pH 6. The PMT model indicated an adsorption capacity (Qm) of 21.14 mg g−1, with an error of 5.75%, demonstrating high precision compared to the experimental result. Additionally, the calculated R2 values equal to or above 0.90 indicated strong agreement between the PMT model and experimental data.
Dan Luo, Shuqian Xia, Lixiao Guo, Yang Liu, Yuhang Zhang, Zhiting Gao, Yahua Gao
BACKGROUND
The production of value-added chemicals from pyrolysis oil or its fractions is of great significance for the valorization of biomass. Diols, including ethylene glycol (EG) and 1,2-propylene glycol (1,2-PG), are important bulk chemicals with widespread industrial applications. Here we investigated the production of diols from pyrolysis oil water-soluble fraction (WS) using a hybrid catalyst (Ni + H2WO4).
RESULTS
Firstly, levoglucosan, glycolaldehyde and acetol, three main components in WS, were respectively selected as the single model compound, and their respective conversions into diols were investigated at different temperatures for different reaction times. The result showed the optimum reaction temperature and time were 180 °C and 2 h respectively, under which a EG yield of 53.8% and 1,2-PG yield of 5.2% were obtained from levoglucosan conversion, a EG yield of 98.6% was obtained from glycolaldehyde conversion, and a 1,2-PG yield of 98.5% was obtained from acetol conversion. The reaction pathway of levoglucosan conversion was analyzed. Secondly, the model mixture of levoglucosan, glycolaldehyde and acetol was used to simulate the real WS, and their conversion was investigated at different ratios of H2WO4 to Ni. The result showed the optimum catalyst composition was 0.15 g H2WO4 and 0.3 g Ni, under which a EG yield of 76.4% and 1,2-PG yield of 38.4% were obtained. Thirdly, the real original WS was converted under the optimum reaction conditions and the result only gave a EG yield of 19.1% and 1,2-PG yield of 25.8% (based on the carbon moles of main substrates), which were much less than the two yields of model mixture. That was related to the presences of other types of chemicals in original WS. After the original WS being adsorbed by activated carbon, the yields of EG and 1,2-PG could be increased to 39.2% and 37.9%, respectively.
To investigate the recovery of molybdate from water and hydrodesulfurization catalysts, a novel synthesized phosphonate Schiff base, 4,4′-(((2,2-dimethylpropane-1,3-diyl) bis(azaneylylidene)) bis(methaneylylidene)) bis(2-methoxyphenol) (HMI) and 4-(((3-((4-(((S)-hydroxyhydrophosphoryl)oxy)-3-methoxybenzylidene) amino)-2,2-dimethylpropyl)imino)methyl)-2-methoxyphenyl hydrogen phosphonate (HIMP), was utilized. This study aimed to assess the structural and property aspects of this synthesized compound using diverse characterizations, including FTIR, Thermogravimetric Analysis (TGA), mass spectrometry (GC–MS), fluorescence transfer spectra, scanning electron microscopy (SEM), and 1H-NMR, 13C-NMR, and 31P-NMR.
RESULTS
The study systematically examined several factors controlling molybdate recovery, including temperature, adsorbent dosage, pH, interaction time, and molybdate concentration using the batch technique. Optimal sorption effectiveness was achieved at pH 2, with an interaction time of 40 min, a 0.06 g adsorbent dose, at ambient temperature. The newly devised adsorbent exhibited an impressive adsorption capacity (Qe) of 372.54 mg of Mo per gram, with empirical data fitting the Langmuir and D-R adsorption models. The kinetics of molybdate uptake followed second-order kinetics. Thermodynamic aspects, including ΔG°, ΔS°, and ΔH°, were also investigated, providing appreciated perceptions into the energetic dynamics of the sorption process. Additionally, molybdate adsorption in the occurrence of other ions was explored, highlighting the selectivity of the modified phosphonate Schiff base for molybdate removal.
Atrazine is present in aquatic systems as a pesticide, and poses a serious threat to ecosystems and human health. The advanced oxidation technology based on persulfate is considered a promising approach for removing trace pesticides from water. The synthesis of a persulfate activator for the rapid and efficient degradation of atrazine was studied.
RESULTS
A novel rod-like sulfur-doped Co3O4 (S-Co3O4) was prepared via the hard template method and used as a persulfate activator to degrade atrazine. The removal efficiency of atrazine (10 mM) could be up to 100% in the presence of peroxymonosulfate (1 mM) activated by S-Co3O4 (50 mg L−1) within 7 min.
Ayman El-Sawaf, Dina A. Tolan, Maiada S. Abdelrahman, Islam Abd El-Hay, Mohamed Ismael, Abdelaal S. A. Ahmed, Emad A. Elshehy, Mahmoud T. Abdu
BACKGROUND
Mesoporous-nanostructured silica-Prussian blue composite is a highly potential material for silver ions removal and recovery from wastewater. Intense interest has been shown in the use of Prussian blue (PB), one of the important coordinated materials and its analogues in removal of toxic and valuable ions.
METHODS
The micro-emulsion template method enables the synthesis of Prussian blue (PB) within silica pores, yielding a nanostructured mesoporous silica-PB composite. This rapid synthesis technique allows for the direct fabrication of the composite from mixed precursor solutions within minutes. The resulting material is effective for selectively extracting silver ions from wastewater at a specific pH level.
Imran Ali, Alexey Yu Isaev, Yana M Chichigina, Daniil D Nakov, Gulnara N Shigabaeva, Evgeny V Galunin, Marcello Locatelli, Zainab M Almarhoon
BACKGROUND
The present work describes the facile, fast and economic base-catalyzed acylation of benzenediols with vinyl acetate. The Hirshfeld surface analysis of benzene-1,4-diol O,O′-diacetate is also described. NaOH, KOH and K2CO3 were the bases used for the catalysis of the acylation of benzene-1,x-diols (x = 2, 3, 4) with vinyl acetate to obtain the corresponding O,O′-diacetyl derivatives.
RESULTS
The yields were quite good, up to 99% under solvent-free conditions. This method represents an alternative ‘green’ process for the preparation of O-acetyl derivatives of hydroxyaryls. The benzene-1,4-diol O,O′-diacetate crystal structure was obtained and described using Hirshfeld surface analysis. A noticeable contribution of the C⋯H contacts is shown (16.7%), despite the insignificant area of the Hirshfeld surface occupied by the carbon atoms (9.4%). By using two-dimensional fingerprint plots, it was proved that C⋯H contacts were due to the presence of π-stacking. The O⋯H contacts (41.4%) were the most numerous ones, relating mainly to typical hydrogen bonds (de + di ≈ 2.6 Å). The high saturation of the C⋯H and O⋯H contacts (enrichment ratios (E) = 1.30 and 1.36, respectively), despite their smaller contribution to the overall surface as compared to the H⋯H contacts (E = 0.84), is shown.
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