Cannabis plant has long been execrated by law in different nations due to the psychoactive properties of only a few cannabinoids. Recent scientific advances coupled with growing public awareness of cannabinoids as a medical commodity drove legislation change and brought about a historic transition where the demand rose over ten-fold in less than five years. On the other hand, the technology required for cannabis processing and the extraction of the most valuable chemical compounds from the cannabis flower remains the bottleneck of processing technology. This paper sheds light on the downstream processing steps and principles involved in producing cannabinoids from Cannabis sativa L. (Hemp) biomass. By categorizing the extraction technology into seed and trichome, we examined and critiqued different pretreatment methods and technological options available for large-scale extraction in both categories. Solvent extraction methods being the main focus, the critical decision-making parameters in each stage, and the applicable current technologies in the field, were discussed. We further examined the factors affecting the cannabinoid transformation that changes the medical functionality of the final cannabinoid products. Based on the current trends, the extraction technologies are continuously being revised and enhanced, yet they still fail to keep up with market demands.

Heteroatom doping is regarded as a promising method for controlling the optoelectronic properties of carbon nanodots (CNDs), notably their fluorescence and antioxidation activities. In this study, phosphorous (P) and boron (B) are doped at different quantities in the CNDs’ structures to investigate their effects on the optical and antioxidation properties. Both the dopants can enhance light absorption and fluorescence, yet via different approaches. After doping, the UV–vis absorption of high P%-CNDs demonstrated a slight blue shift (348–345 nm), while the high B%-CNDs showed a minor red shift (348–351 nm), respectively. The fluorescence emission wavelength of doped CNDs changes marginally while the intensity increases significantly. Structural and composition characterizations show elevated levels of C=O on the surface of high P%-CND compared to low P%-CNDs. In B-doped CNDs, more NO 3 – functional groups and O–C=O bonds and fewer C–C bonds form at the surface of high B%-CNDs compared to the low B%-CNDs. A radical scavenging study using 2,2-diphenyl-1-picrylhydrazyl (DPPH) was carried out for all CNDs. It was found that the high B%-CNDs exhibited the highest scavenging capacity. The effects of the atomic properties of dopants and the resulting structures of CNDs, including atomic radius, electronegativity, and bond lengths with carbon, on the optoelectronic property and antioxidative reactions of CNDs are comprehensively discussed. It suggests that the effect of P-doping has a major impact on the carbogenic core structure of the CNDs, while the B-doping mainly impacts the surface functionalities.

This work describes the stripping and refining of cannabidiol (CBD) from hemp extracts using a wiped-film molecular distillation (WFMD) system. The process takes place in two stages, where the CBD gets stripped in the first stage and refined in the second stage. The main feed encompassing decarboxylated hemp extracts enters the stripping step at a CBD concentration of about 35.8 wt % and leaves at 48.0 wt %, where the majority of terpenes leave the extracts. In the refining stage, the effects of process conditions, including pressure, evaporation temperature, and condensation temperature, were examined using the response surface methodology (RSM) toward the maximum CBD concentration and recovery. A second-stage recovery of 92.66 wt % was achieved at the concentration of 80.19% by applying a pressure of 40 Pa, an evaporation temperature of 170 °C, and an internal condenser temperature of 20 °C. Analysis of the product showed that a low-pressure operation did not remove tetrahydrocannabinol from the CBD-rich product, thus proving to be an improper choice of WFMD for removing the psychoactive component. It was also found that the pressure reduction and increases in evaporation and condensation temperatures were contributing to higher CBD concentrations, although the condensation temperature had no effect on the recovery amount. The RSM and artificial neural network were further tested to assess their prediction capacity toward the efficiency and process performance. It was found that both models offer satisfying prediction capability, although the RSM had larger margins of error.

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