Αλέξανδρος Γ. Σφακιανάκης: 01/14/19

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Monday, January 14, 2019

Black carbon: source apportionment and its implications on CCN activity over a rural region in Western Ghats, India

Abstract

This study presents the characteristics of black carbon aerosol (BC) over a high-altitude site, Mahabaleshwar during the monsoon season. The mass concentration of BC exhibits a morning peak and a daytime build-up with a mean mass concentration of 303 ± 142 ng m⁻³. The simultaneous measurements of aerosol particle number concentration (PNC), cloud condensation nuclei concentration (CCN), and non-refractory particulate matter less than 1 μm size (NR-PM₁) were also made by using a Wide-Range Aerosol Spectrometer (WRAS), CCN counter and Aerosol Chemical Speciation Monitor (ACSM) respectively. The source apportionment using wavelength-dependent light absorption model reveals the dominance by wood burning sources during morning hours and traffic sources during remaining hours of the day. The diurnal variation of PNC follows the variability of BC mass concentration. However, CCN concentrations were high during the morning hours coinciding with the increased fractional contribution of organics. The k-means clustering coupled with fuzzy algorithm highlights the effect of different sources on aerosol size distribution. On the basis of size distribution curve, the 3 clusters were attributed to wood burning (mean diameter range: 50–100 nm), traffic (30–50 nm), and background aerosols (65–95 nm). The combined analysis of k-means clustering, fractional contribution of organics, and kappa variation suggests that higher CCN concentration during morning is mainly attributed to probable emission of the water-soluble organic/inorganic compounds from wood burning.

from Climate Change Skeptic Blogs via hj on Inoreader http://bit.ly/2Ck6wuF

Adsorption of phosphorus by using magnetic Mg–Al-, Zn–Al- and Mg–Fe-layered double hydroxides: comparison studies and adsorption mechanism

Abstract

Mg–Al, Zn–Al and Mg–Fe magnetic layered double hydroxide (LDH) adsorbents were synthesized. The adsorption effect and influencing factors of these adsorbents were explored, and the adsorption mechanism of phosphorus was studied with advanced instruments. The results showed that the best adsorption performance was observed when the molar ratio of metals was 3 for the magnetic LDH adsorbents, and the maximum adsorption amount for phosphorus was 74.8, 80.8 and 67.8 mg/g for Mg–Al, Zn–Al and Mg–Fe LDHs, respectively. Pseudo-second-order kinetics could be used to describe the adsorption process of phosphorus onto the magnetic LDHs. The adsorption of phosphorus onto the magnetic LDHs was an exothermic process. Lower temperatures were favourable for adsorption, and the adsorption of phosphorus onto the magnetic LDHs was a spontaneous process. When the solid–liquid ratios were 0.10 g/L, 0.10 g/L and 0.05 g/L for Mg–Al, Zn–Al and Mg–Fe magnetic LDHs, respectively, the highest adsorption amount of phosphorus was achieved for each magnetic LDH. The maximum adsorption amount was observed at pH values of 6.0–8.0. The inhibitory effect of HCO₃⁻ on the adsorption capacity of phosphorus onto the magnetic LDHs was the strongest at a higher HCO₃⁻ concentration level. The relative content of –OH significantly reduced after adsorption of phosphorus by the FTIR analysis, which indicated that the mechanism of phosphorus removal was mainly through the exchange between hydroxyl on the adsorbent surface and phosphorus in water. XPS studies showed that oxygen provided electrons during the adsorption of phosphorus.

from Climate Change Skeptic Blogs via hj on Inoreader http://bit.ly/2RsHmUZ

Spatial econometric analysis of carbon emission intensity in Chinese provinces from the perspective of innovation-driven

Abstract

This study estimates the carbon emission intensity of China's provinces during the period from 2000 to 2015. First, the temporal and spatial pattern evolution of China's carbon emission intensity was analyzed using spatial statistics. Then, from an innovation-driven perspective, combining the data of innovative technologies and scale factors to construct a spatial panel model to explore the main influencing factors of carbon emission intensity and its spatial spillover effect. The results show that: China's provincial carbon emission intensity has obvious spatial agglomeration characteristics, and regional differences are improving, and the spatial spillover effect of some influencing factors is obvious; innovation indicators such as the number of patent authorizations, technical market turnover, and foreign direct investment, and GDP have a significant negative impact on carbon intensity, and the effects of general scale variables such as urbanization rate, energy consumption, and population density on carbon intensity are significantly positive.

from Climate Change Skeptic Blogs via hj on Inoreader http://bit.ly/2Ci5PSs