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The influence of tree age on the growth response of Picea likiangensis, a predominant timber species in southwestern China, to climatic factors has been under-researched. In this study, we examined the relationships between tree age and the response of P. likiangensis to climatic factors and extreme drought events using tree-ring samples procured from the southeastern edge of the Tibetan Plateau. The results revealed differential responses of the radial growth of P. likiangensis trees of varying ages to climatic factors and extreme drought events. Specifically, deficient water availability during the early growing season emerged as the principal factor constraining radial growth across all age classes. Young and middle-aged trees (<100 years) demonstrated greater responsiveness to water availability than did mature trees (>100 years). Mature trees, in contrast, demonstrated markedly greater resistance to extreme drought events than young and middle-aged trees. Comparative studies of individual trees across different ages revealed negligible differences in the response of young and middle-aged trees to climatic factors and extreme drought events. Given these responses, future forest management practices should prioritize young and middle-aged trees that are more affected by drought to maximize the ecological value of the species. According to the specific research objectives, sample collection processes should classify mature trees and young and middle-aged trees, to minimize the influence of tree age on the final findings of the study., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this study, ozone-oxidation was used to treat synthetic chemical plating solution containing Cu(II)/Ni(II)-EDTA solution to realize the purpose of decomplexation. The effects of solution pH, initial concentration of Cu(II)/Ni(II)-EDTA, the molar ratio of EDTA to Cu(II)/Ni(II), and the coexistence of Cu(II)/Ni(II) on their removal efficiencies were investigated. The degradation of EDTA-Cu(II) and EDTA-Ni(II) were mainly attributed to OH oxidation, and the removal rates of Cu(II)/Ni(II) depend on the complete decomplexation. The removal rates of Cu(II) and Ni(II) was affected by the pH of solution, and the optimal pH was found to be 7-9; nevertheless, their removal rates can still be up to 90% even in acidic pHs of 3~5. When the molar ratio of EDTA to Cu(II)/Ni(II) increased from 1:1 to 3:1, the kinetics of metal ion removal rate declined from 0.0788 and 0.1139 min -1 to 0.0250 and 0.0271 min -1 . The synergistic effect was found in the Cu(II)/Ni(II) blended system due to the higher catalytic capability and the lower complexation affinity toward EDTA for Ni(II). In summary, ozone oxidation can be considered as an effective technology to realize the complete decomplexation of Cu(II)/Ni(II)-EDTA that contained in chemical plating industry wastewater. Graphical Abstract.

Thermal hydrolysis has proven to be a successful approach to make sewage sludge more amenable to anaerobic digestion. Three heat pretreatment scenarios were compared in this study, i.e. thermal alkaline treatment (LAT, 0.1 M NaOH, 80 °C), low temperature thermal treatment (LT, 80 °C) and high temperature thermal treatment (HT, 170 °C). The biodegradability of pretreated sludge was testified by using biochemical methane potential (BMP) test, meanwhile, the repartition and complexities of organic matters in sludge subjected to various pretreatments were characterized by a revised chemical extraction protocol combined with 3D fluorescence spectroscopy. The cumulative methane yield of sewage sludge was significantly increased by LAT (+135%), LT (+95%) and HT (+112%) as compared to the control. Nevertheless, results show that the solubilization degree of sludge was insignificantly correlated to BMP values, meanwhile high correlation values were observed for the soluble polysaccharide concentration in hydrolysate. The degradation rates of bioaccessible fraction of soluble particulate organic matter (SPOM) and readily extractible organic matter (REOM) were improved after thermal pretreatments at varied levels, which indicates that the chemical accessibility is positively correlated with the bioaccessibility. Furthermore, the biodegradable index F digestion was proposed to evaluate the biodegradability of organic matter, which is helpful for the optimization of various pretreatment strategies., (Copyright © 2019 Elsevier Ltd. All rights reserved.)