Biomass porous carbon as the active site to enhance photodegradation of oxytetracycline on mesoporous g-C3N4

A novel mesoporous g-C3N4 loaded with biomass porous carbon was synthesized by molten salt assisted thermal polycondensation, and the formation of hollow tubular structure increased the specific surface area.

Graphitic Carbon Nitride as a Platform for the Synthesis of Silver Nanoclusters

Graphitic carbon nitride (CN) synthetized by the thermal polycondensation of melamine at 550 °C for 4 h was further exfoliated by heating at 500 °C for 3 h. Silver cations were adsorbed on the exfoliated graphitic carbon nitride (CNE) and then reduced by sodium borohydride forming silver nanoclusters (NCs) with a size of less than 1 nm. The NCs were located on the CNE surface and did not change the CNE properties except for its pore size distribution and thereby specific surface area (SSA). The Ag NCs were able to collect the photoinduced electrons of CNE and thus reduce their recombination with the holes. It was also documented by the increase in the CNE photocatalytic activity in terms of the degradation of antibiotic Ofloxacin. This study demonstrates the ability of CNE to serve as a platform for a simple and fast synthesis of Ag NCs without any stabilizing compounds. Graphic Abstract

Study of Dependence of Softening Point on Mesophase Content of Petroleum Pitches from Heavy Pyrolysis Resin and Decantoil

Samples of petroleum pitches were obtained from heavy pyrolysis resin and decantoil (heavy gas-oil of catalytic cracking) by thermal polycondensation at atmospheric pressure, temperatures of 380–400 and 410–440°С (for resin and decantoil, respectively) and isothermal holding time of 30–480 min. Analysis of the dependence of the softening point on the mesophase content for the obtained samples showed that at the same mesophase content, decantoil pitches exhibit a lower softening point compared to pyrolysis resin pitches, for which, even at 30 % mesophase, the softening point approaches 300°C. This suggests that it is impossible to obtain pitch from pyrolysis resin with high mesophase content without preliminary preparation (for example, by hydrogenation). On the other hand, it has been shown that for pitches from decantoil, it is possible to isolate the mesophase up to 65% or more with a softening point not higher than 250°C.

Highly dispersed Ag nanoparticles in situ creating rich cyano defects in carbon nitride for efficient photocatalytic H2 production

Uniformly Ag nanoparticles, rich cyano defects, and conjugated carbon dopants were simultaneously implanted into carbon nitride framework by a one-step thermal polycondensation method. The abundant cyano defects act as charge...

Thermopolycondensation of Vacuum-Disposed Cracking Residue for Obtaining Petroleum Pitch Suitable for Production of Carbon Materials

The article emphasizes the relevance and expediency of developments for the creation of petroleum pitch and the introduction of thermal polycondensation processes in Russia. The possibility of producing petroleum pitches from vacuum-distilled cracking residue is considered. It is shown that to obtain a petroleum pitch suitable for carbon materials, it is necessary to carry out the process of thermal polycondensation in two stages: at elevated pressure, and then at reduced pressure. The physicochemical properties of the obtained petroleum pitches and intermediate products of the process have been investigated. The possibility of obtaining petroleum pitches with a yield of 35-38% wt. from the vacuum distilled cracking residue at the thermal polycondensation unit.

Thermal Polycondensation Process and Oil Furnace Production

The article discusses the methods of obtaining petroleum pitch of thermal polycondensation. The main attention is paid to the characteristics of petroleum pitch, its properties, its comparison with coal-tar pitch, the advantages of petroleum pitch in comparison to coal-tar pitch, the processes of production of petroleum pitch by thermal polycondensation are given. Three promising technologies for the production of petroleum pitch have been identified: thermal polycondensation of cracking residue, high-temperature thermal polycondensation of petroleum feedstock and thermal polycondensation of pyrolysis resin according to a two-stage scheme. Methods of obtaining petroleum pitch in laboratory conditions, such as thermal polycondensation under pressure and heat treatment under reduced pressure, are presented. The urgency and feasibility of developments for the creation of petroleum pitch and the introduction of thermopoly-condensation processes in Russia is emphasized.

Synthesis of Poly (Citric Acid-Co-Glycerol) and Its Application as an Inhibitor of CaCO3 Deposition

This investigation determined a feasible route to prepare hyperbranched polyesters involving citric acid (CA) and glycerol (GLC) monomers (CA-co-GLC) using a thermal polycondensation method. The synthesized copolymer was characterized using Fourier transform infrared spectroscopy (FT-IR), carbon-13 nuclear magnetic resonance spectroscopy, and differential scanning calorimetry. The ability of CA-co-GLC to inhibit deposition of inorganic scales such as calcium carbonate was investigated under varying temperature and pH medium. The evaluation of inhibition efficiency (IE) was conducted using the static scale inhibition method. The mechanism of the inhibitor’s action was investigated via growth solution analysis, measurement conductivity, and analysis of CaCO3 using FT-IR and scanning electron microscopy. The results obtained showed that the CA-co-GLC had good IE at an elevated temperature reaching 75% at 100 °C, pH 7.5, and 10 ppm copolymer dose. Using the same dose, the IE reached 66% at 50 °C and pH 10. The CA-co-GLC did not chelate Ca2+ in water, but led to a change in polymorphism, making it brittle and able to slip easily from the surface. Its action principally prevented the adhesion of calcium carbonate onto the surface.