Analysis of fading mechanism of salix integra dyed with reactive dye under ultraviolet irradiation by tri-step infrared spectroscopy

Experimental investigation on pyrolysis of coking waste salts: Mechanism of organic compounds removal and salt agglomeration

Evaporative crystallization of high-salinity wastewater produces hazardous waste salts. This study aimed to investigate coking waste salt (CWS) and employed pyrolysis to eliminate organic impurities. The pyrolysis mechanism, properties, and agglomeration characteristics of CWS were examined. Results showed that pyrolysis disrupts the functional groups of organic compounds, but benzene rings are resistant to removal. Below 500 °C, pyrolysis in air was more effective than pyrolysis in N2, whereas above 500 °C, the difference between pyrolysis in air and N2 was negligible. Agglomeration was primarily attributed to deliquescence caking, pyrolysis of organic matter, and low-melting-point salts. The optimal disposal method for CWS involved drying and crushing, followed by pyrolysis in air at 450 °C. This process minimized agglomeration and maximized organic matter removal. Our findings provide a robust theoretical basis and practical guidance for waste salt resource utilization.

The removal of organic impurities from industrial waste salt by pyrolysis

The presence of organic impurities hinders the resource utilization of industrial waste salt (IWS). In this study, pyrolysis treatment was chosen to remove these organic impurities. The optimal process parameters for the pyrolysis of organic impurities were as follows: a temperature of 500 °C and a holding time of 20 min. Under these optimal conditions, the total organic carbon (TOC) removal rate was 96.32%, inducing a decrease in the TOC mass fraction from 1.88 to 0.08%. Fourier transform infrared spectroscopy (FTIR) results obtained during this process showed that prolonging the pyrolysis time (10-70 min) for IWS resulted in a gradual decrease in the relative content of characteristic functional group, such as C-O in ether groups, and the disappearance of functional group, such as benzophenone carbonyl group and ester carbonyl. Organic impurities can release gas-containing compounds that destroy the initially smooth IWS surface, and the resulting particles with rough and irregular shapes fuse into large or lumpy particles during the pyrolysis process. GC‒MS results clearly showed that the number of different semivolatile organic compounds in the IWS was reduced from 35 to 19 as a result of the pyrolysis process. Correspondingly, organic impurities with molecular formulas containing 5-10 carbon atoms converted into compounds containing 6-20 carbon atoms. These findings provide theoretical support for IWS resource utilization.

Continuing progress in the field of two-dimensional correlation spectroscopy (2D-COS): Part III. Versatile applications

In this review, the comprehensive summary of two-dimensional correlation spectroscopy (2D-COS) for the last two years is covered. The remarkable applications of 2D-COS in diverse fields using many types of probes and perturbations for the last two years are highlighted. IR spectroscopy is still the most popular probe in 2D-COS during the last two years. Applications in fluorescence and Raman spectroscopy are also very popularly used. In the external perturbations applied in 2D-COS, variations in concentration, pH, and relative compositions are dramatically increased during the last two years. Temperature is still the most used effect, but it is slightly decreased compared to two years ago. 2D-COS has been applied to diverse systems, such as environments, natural products, polymers, food, proteins and peptides, solutions, mixtures, nano materials, pharmaceuticals, and others. Especially, biological and environmental applications have significantly emerged. This survey review paper shows that 2D-COS is an actively evolving and expanding field.