Optimization of operating conditions for the catalytic alcoholysis of waste PET for the synthesis of BHET by sunflower seed husk matrix materials.

A sunflower seed shell matrix catalyst (SMS-750) was prepared from sunflower seed shell waste by pretreatment and pyrolytic carbonization. A series of characterization analyses showed that the prepared catalyst was rich in Ca, Mg, K, and other mineral elements and mainly existed in the form of metal oxides. SMS-750 was used to catalyze the glycolysis of waste PET, and the main factors affecting the BHET yield were screened out by a one-way experimental design, and then the BHET yield was used as the response value, and the response surface method was used to design and analyze the effects of the respective variables and their interactions on the degradation of PET according to the principle of Box-Behnken central combinatorial design.

Congestion control in internet of things (IoT) using auction theory.

The Internet of Things (IoT) facilitates data transmission through communication networks, preventing congestion when input data rate exceeds output, and congestion control in computer networks modulates traffic entry. This paper proposes a fusion of auction theory with reinforcement learning as a means of managing congestion in the IoT. The proposed technique seeks to enhance network performance by utilizing object trustworthiness evaluation and auction-based route selection to manage congestion during data routing.

Synthesis of azelaic acid copolyester plasticizers and their application in PVC.

A series of 2-methyl-1,3-propanediol (MPO) modified azelaic acid and hexylene glycol copolyester (PHMAZ) plasticizers with varying contents were synthesized using a direct esterification melt polycondensation method, and their structures were characterized systematically. Analysis using infrared spectroscopy and nuclear magnetic resonance spectroscopy confirmed the synthesis of the designed copolyester structure. Gel permeation chromatography (GPC) tests indicated that the number average molecular weight of each copolyester sample ranged between 2000 and 3000.

Ti-Si composite glycol salts: depolymerization and repolymerization studies of PET.

In this study, a Ti-Si-ethylene glycol salt (Ti/Si-EG) was synthesized and used as a catalyst for the depolymerization of PET-ethylene glycol to produce bis(hydroxyethyl)terephthalate (BHET), and the optimum conditions for the depolymerization were determined by response surface analysis: (EG) : (PET) was 4 : 1, the catalyst mass dosage was 0.56% (in terms of the mass of PET), the depolymerization temperature was 203 °C, the depolymerization time was 3.8 h, and the highest yield of the product (BHET) was 90.

Research progress of metal-organic framework-based material activation of persulfate to degrade organic pollutants in water.

The rapid development of industry in recent years has led to the introduction of serious pollutants into water bodies, and there is an urgent need for efficient organic degradation technologies. At present, selective peroxynitrite (PS) oxidation (SR-AOPs) is an effective way to treat pollutants in water bodies, and it is necessary to select a suitable material for the activation of peroxynitrite. Metal-organic frameworks (MOFs), with their tunable structure, large specific surface area, and tunable ligand molecules exhibit excellent reactivity and catalytic performance in the activation of persulfate.

Optimization of Ti-BA efficiently for the catalytic alcoholysis of waste PET using response surface methodology.

A titanium benzoate (Ti-BA) catalyst was prepared by hydrothermal method, which has an ordered eight-face structure, and was used for polyethylene terephthalate (PET) depolymerization. With bis(2-hydroxyethyl)terephthalate (BHET) as the target molecule and ethylene glycol (EG) as the solvent, the best reaction conditions for catalytic alcoholysis a PET alcoholic solution were investigated response surface experiments and found to be a EG/PET mass ratio of 3.59, temperature of 217 °C and reaction time of 3.

Research and progress of chemical depolymerization of waste PET and high-value application of its depolymerization products.

PET (polyethylene terephthalate) has good transparency, corrosion resistance, gas barrier properties and mechanical properties, and is widely used in beverage bottles, fabrics, food packaging, tires, films, engineering plastics and other fields. With the rapid growth in demand and use of PET materials, the pollution of waste PET to the environment has become increasingly prominent. The recycling methods of waste PET mainly include primary recycling, mechanical recycling, chemical recycling, and energy recycling.

Separation performance of -butyl(tetradecyloxy)calix[6]arene as a stationary phase for capillary gas chromatography.

This work presents the first example of the utilization of -butyl(tetradecyloxy)calix[6]arene (C6A-C10) as a stationary phase for capillary gas chromatographic (GC) separation. The statically coated C6A-C10 column showed a column efficiency of 3293 plates per m and had a nonpolar nature. Its selectivity and retention behaviour were investigated using a number of mixtures of diverse analytes and their isomers.

Star-poly(ε-caprolactone) as the stationary phase for capillary gas chromatographic separation.

This work presents the separation performance of star-poly(ε-caprolactone) (star-PCL) as the stationary phase for capillary gas chromatography (GC). The statically coated star-PCL column showed a column efficiency of 3345 plates per m and moderate polarity. Importantly, the star-PCL column exhibited high selectivity and resolving capability for more than a dozen mixtures covering a wide-ranging variety of analytes and isomers.

Performance and selectivity of lower-rim substituted calix[4]arene as a stationary phase for capillary gas chromatography.

This work presents the investigation of -butyl(tetradecyloxy)calix[4]arene (C4A-C10) as stationary phase for capillary gas chromatographic (GC) separations. The statically-coated C4A-C10 capillary column showed weak polarity and column efficiency of 2566 plates per m determined by -dodecane at 120 °C. Impressively, the C4A-C10 column exhibited extremely high resolving capability for a wide range of analytes from nonpolar to polar, including -alkanes, esters, ketones, aldehydes, alcohols and bromoalkanes.

Catalytic conversion of CO into propylene carbonate in a continuous fixed bed reactor by immobilized ionic liquids.

In this study, functionalized composite catalysts, namely, ILs (ILX/(ZnBr)), with hydroxyl, carboxyl and amino groups immobilized on a molecular sieve (MCM-22) support were synthesized with the help of a silane coupling agent, 3-chloropropyltriethoxysilane (CPTES). Cycloaddition of CO and propylene oxide (PO) was carried out in a fixed bed reactor. The results show that MCM-22-CPTES-[AeMIM][ZnBr] demonstrates the best catalytic properties for this reaction.