Removal of phenol in aqueous solution by adsorption onto green synthesized coinage nanoparticles beads

The adsorption of phenol from aqueous solution was carried out by using alginate-stabilized silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) beads as adsorbents. The resulting AgNPs and AuNPs were characterized by scanning electron microscope, UV-visible spectroscopy and Fourier transform infrared spectroscopy. Batch adsorption studies have shown that removal is dependent upon process parameters like initial concentration, contact time, pH and adsorbent dosage. The adsorption data obtained from batch studies at optimized conditions have been subjected to Freundlich and Langmuir isotherm studies. The pseudo-first-order and pseudo-second-order kinetic models were also applied to the experimental data. Phenol was effectively (90.0 +/- A 0.8 %) removed from the aqueous solution using alginate-stabilized AuNPs beads as the adsorption process. Desorption studies were made to elucidate recovery of the adsorbate and adsorbent for the economic competitiveness of the removal system. The alginate-stabilized AgNPs and AuNPs beads were found to be good adsorbents for adsorption of phenol from the aqueous solution

Seasonal Characteristics of Biogenic Secondary Organic Aerosols Over Chichijima Island in the Western North Pacific: Impact of Biomass Burning Activity in East Asia

To better understand the formation processes of biogenic secondary organic aerosols (SOAs) over remote oceanic regions, aerosol samples were collected from 2010 to 2012 at Chichijima Island in the western North Pacific (WNP). The samples were analyzed by gas chromatography-mass spectrometry for SOA tracers, which are produced by the photochemical oxidation of biogenic volatile organic compounds (BVOCs), including isoprene, monoterpenes, and sesquitepenes. Although no seasonal trend was identified for the isoprene-derived SOA tracers, we observed higher levels of the monoterpene-derived and sesquiterpene-derived SOA tracers in winter/spring and lower levels in summer/autumn. We found a significant correlation (r = 0.87) of beta-caryophyllinic acid with levoglucosan, the latter being a specific tracer of biomass burning (BB). This suggests that the beta-caryophyllene accumulated in higher plants is evaporated by BB followed by atmospheric oxidation during long-range transport from the Asian continent over the WNP. The biogenic secondary organic carbon concentration estimated using a tracer-based approach ranged from 0.11 to 174 ngC m(-3) (avg. 34.8 +/- 38.2 ngC m(-3)), accounting for 0.02%-32.0% (avg. 6.11% +/- 6.42%) of the measured organic carbon. Our results indicate that SOAs are formed by the photooxidation of BVOCs. The backward trajectories of air masses further support their transport from the central Pacific during mid-spring to mid-autumn, whereas BB aerosols are transported from the Asian continent during mid-autumn to mid-spring over the WNP. Positive matrix factorization analyses of the SOA tracers suggest that organic aerosols of Chichijima are mostly related to BVOC emissions, with BB's additional contributions especially in winter and spring

Abundance, chemical structure, and light absorption properties of humic-like substances (HULIS) and other organic fractions of forest aerosols in Hokkaido

Abstract Atmospheric organic aerosol (OA) are considered as a significant contributor to the light absorption of OA, but its relationship with abundance, composition and sources are not understood well. In this study, the abundance, chemical structural characteristics, and light absorption property of HULIS and other low-to-high polar organics in PM0.95 collected in Tomakomai Experimental Forest (TOEF) were investigated with consideration of their possible sources. HULIS were the most abundant (51%), and correlation analysis revealed that biogenic secondary organic aerosols significantly contribute to HULIS. The mass spectra obtained using a high-resolution aerosol mass spectrometer (HR-AMS) showed that HULIS and highly polar water-soluble organic matter (HP-WSOM) were substantially oxygenated organic aerosol fractions, whereas water-insoluble organic matter (WISOM) had a low O/C ratio and more hydrocarbon-like structures. The WISOM fraction was the predominant light-absorbing organics. HULIS and WISOM showed a noticeable seasonal change in mass absorption efficiency (MAE365), which was highest in winter. Further, HULIS were shown to be less absorbing than those reported for urban sites. The findings in this study provide insights into the contribution of biogenic secondary OA on aerosol property and radiative forcing under varying contributions from other types of OA

Removal of phenol in aqueous solution by adsorption onto green synthesized coinage nanoparticles beads

The adsorption of phenol from aqueous solution was carried out by using alginate-stabilized silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) beads as adsorbents. The resulting AgNPs and AuNPs were characterized by scanning electron microscope, UV-visible spectroscopy and Fourier transform infrared spectroscopy. Batch adsorption studies have shown that removal is dependent upon process parameters like initial concentration, contact time, pH and adsorbent dosage. The adsorption data obtained from batch studies at optimized conditions have been subjected to Freundlich and Langmuir isotherm studies. The pseudo-first-order and pseudo-second-order kinetic models were also applied to the experimental data. Phenol was effectively (90.0 +/- A 0.8 %) removed from the aqueous solution using alginate-stabilized AuNPs beads as the adsorption process. Desorption studies were made to elucidate recovery of the adsorbate and adsorbent for the economic competitiveness of the removal system. The alginate-stabilized AgNPs and AuNPs beads were found to be good adsorbents for adsorption of phenol from the aqueous solution