The effect of extraction methods on the components and quality of Camellia oleifera oil: Focusing on the flavor and lipidomics.

The objective of this study was to systematically elucidate the effects of conventional (Cold Pressing, CP; Hot Pressing, HP; Soxhlet Extraction; SE) and novel methods (Microwave-Assisted Extraction, MAE) on the physicochemical properties, bio-active substances, flavor and lipidomics of Camellia oleifera oil (COO). The cold-pressed COO contained the highest contents of squalene (176.38 mg/kg), α-tocopherol (330.52 mg/kg), polyphenols (68.33 mg/kg) and phytosterols (2782.55 mg/kg). Oleic acid was observed as the predominant fatty acid with the content of approximately 80%. HS-GC-IMS identified 47 volatile compounds, including 11 aldehydes, 11 ketones, 11 alcohols, 2 acids, 8 esters, 2 pyrazines, 1 furan, and 1 thiophene. A total of 5 lipid classes and 30 lipid subclasses of 339 lipids were identifed, among which TGs and DGs were observed as the major lipids. In summary, both cold-pressed and microwave-assisted technologies provided high-quality COO with high content of bio-active substances and diglycerides/triglycerides.

Extracting copper and cobalt from non-ferrous residues by iron- and sulfur-oxidizing bacteria.

How to recycle metals from the waste resources becomes a hotspot all around the world. Non-ferrous residues, which was produced by non-ferrous melting industry, and various of Cu and Co compounds exist in the residues in the form of CuxOy, CuxSy, CoxSy. In order to efficiently extract valuable metals from the non-ferrous residues, this study investigated the bioleaching behavior of Cu and Co from non-ferrous residues, using iron-oxidizing bacteria (IOB, Leptospirillum ferriphilum CS13) and sulfur-oxidizing bacteria (SOB, Acidithiobacillus caldus S2) by controlling the microbial composition, initial pH, and initial ferrous ion concentration. The results showed that IOB had a better performance on extracting Cu and Co than that of SOB, especially for Cu. Furthermore, 77.7 and 79.8% of Cu and Co were extracted under the optimal ratio of the initial number of IOB and SOB (1:1) after bioleaching, which was more than that when bioleaching by any one of these two kinds of bacteria. However, the changes of initial pH and ferrous ion concentration could not significantly enhance bioleaching performance. The results indicated that bioleaching had a good performance on recovering of metals from non-ferrous residues and excellent application prospect for the cleaner resource recycling.

Bioleaching of Copper-Containing Electroplating Sludge.

The recovery of precious metals from solid waste through bioleaching has become a research hotspot in recent years. Thus, in this study, different strategies, such as chemical sulfuric acid leaching and mixed consortium bioleaching, were adopted to extract copper from Copper-Containing Electroplating Sludge. The results showed that, compared to chemical leaching, bioleaching showed a much better performance. Indeed, copper bioleaching efficiency reached 94.3% on day 7 (21.1% higher than that of chemical leaching). The results also indicated that the process of bioleaching involved more mechanisms and reactions than that of chemical leaching. The SEM and EDX tests showed that the surface morphology of the sludge changed significantly after bioleaching, and that an insignificant amount of copper remained in the leached residues. Furthermore, the leached residues passed the characteristic leaching toxic test and thus can be considered as non-hazardous raw materials for the construction industry. Hence, adopting a mixed consortium leaching process to extract copper from Copper-Containing Electroplating Sludge will not only significantly reduce environmental pollution, but will also use metal resources more efficiently.