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Emissions of biogenic volatile organic compounds (BVOCs) play important roles in ecophysiology and atmospheric chemistry at large spatial and temporal scales. Tropical regions are a main global source of BVOCs and magnitude and chemical compositions are highly variable. This study is based on the measurements of monoterpenes using proton transfer reaction-time of flight-mass spectrometer (PTR-TOF-MS) at a semi-arid site in western India during the winter-to-summer transition. Mixing ratio of monoterpenes showed strong diurnal variation with elevated values from evening till midnight and lowest in the afternoon. The daily data does not show clear trends with monthly means of ~ 0.35 ppbv during each month. Exceptionally high levels of 3 -6 ppbv were measured during the sporadic biomass burning and bonfire event during Holi festival. The daytime data of monoterpenes do not clearly reflect the impact of biogenic emission due to the competing influences of mixing and OH-reaction loss. In the afternoon, the monoterpenes/benzene ratio of 0.43 ppbv ppbv-1 in second half of March was ~ 3 times higher than that in first half of February. It showed strong response with temperature as it increased from 0.27 ppbv ppbv-1 (< 30°C) to 0.50 ppbv ppbv-1 (> 30°C). The dependence with wind speed is represented by exponential decay but rate of decline in February was ~ 2 times greater than that in March. The ratios of monoterpenes/isoprene in the night were significant higher than those during the day indicating light independent but temperature dependent emissions of monoterpenes. The nighttime MTs/isoprene ratio increased from 0.25 ppbv ppbv-1 in the first half of February to 0.43 ppbv ppbv-1 in the second half of March. Overall, the ratios of monoterpenes/isoprene agree with the values reported for a topical forest region in SE Asia. The estimated contribution from local biogenic sources to ambient monoterpenes increased from 31 % in first half of February to 67 % in second half of March. This trend suggests the increasing biogenic contribution from February to March. The NW winds and higher ambient temperatures in March favored the local emissions and regional transport of BVOCs. [ABSTRACT FROM AUTHOR]

This study deals with emission of biogenic volatile organic compounds (BVOCs) from some common plant species found in the Western Ghats of India using branchenclosure experiments. A custom-made dynamic chamber system was deployed to collect samples from seven different plant species. Analysis of speciated BVOCs was performed using C2-C6 and C6-C12 VOC analysers to determine the emission composition and relative concentration. Isoprene was the most abundant compound, followed by ethene, propene, α-pinene and β-pinene. Among the plant species, Tectona grandis, Bambusa vulgaris and Psidium guajava showed high fractions of isoprene emission, Saraca asoca showed moderate emission, and Manilkara zapota and Leucaena leucocephala showed the lowest emission. However, M. zapota and L. leucocephala showed higher emission of both ethene and propene compared to isoprene. This study emphasizes the importance of emission flux measurements of major plant species in different forest regions of India, which is necessary to make emission inventories of important BVOCs. [ABSTRACT FROM AUTHOR]

Industrial wastewater, despite undergoing primary and secondary treatments with conventional methods, continues to pose challenges due to the presence of multiple contaminants. Membrane separation has emerged as an effective solution to streamline the treatment process, yet it often results in surface fouling. This study introduces a single platform designed for simultaneous removal of dyes, oils, and proteins during the tertiary treatment stage, thereby eliminating the need for multiple separation steps. To enhance membrane robustness and address common fouling issues, polyvinylidene fluoride-montmorillonite-cucurbit[6]uril/zinc oxide (PV-M-CB[6]ZnO) mixed-matrix membranes have been developed. The incorporation of montmorillonite (M), cucurbit[6]uril (CB[6]) host-guest encapsulation, and zinc metal chelation significantly improves the membrane's capability in eliminating cationic dyes, treating oil-water emulsions, and separating bovine serum albumin. With an optimal CB[6]/ZnO loading of 1.6 wt%, the PV-M-CB[6]ZnO membranes exhibit superior performance with high water permeability (4114 L/m 2 .h.bar) and exceptional separation efficiencies: 95.5% for malachite green, 93.2% for methylene blue, and 98.2% for crystal violet, compared to pristine PVDF membranes. Additionally, these membranes demonstrate an impressive oil-water rejection rate of 97.6% and a bovine serum albumin rejection rate of 76%, with a flux recovery ratio exceeding 86% after seven filtration cycles. Thus, the PV-M-CB[6]ZnO membranes offer enhanced hydrophilicity, improved antifouling properties, and increased efficiency for the removal of multiple contaminants from industrial wastewater, providing a promising solution for sustainable environmental remediation., 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. Published by Elsevier Ltd.)