Browsing by Author "Li, Shiyin"

Now showing 1 - 3 of 3
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    Efficient removal of sulfamerazine (SMR) by ozonation in acetic acid solution after enrichment SMR from water using granular activated carbon
    (Royal Society of Chemistry, 2019) Yao, Youru; Mi, Na; Zhu, Yongqing; Yin, Li; Zhang, Yong; Li, Shiyin; Nanjing Normal University; University of Alabama Tuscaloosa; Anhui Normal University
    Sulfamerazine (SMR) as a persistent organic pollutant in waste streams is of growing environmental concern. This study explores the extraction SMR from water into an acetic acid (AA) solution using granular activated carbon (GAC), and removal of SMR by ozonation in AA solution. Systematic experiments have shown that GAC can be used as an adsorbent to transfer sulfamerazine from water to AA solution. SMR removal efficiency is 99.5% in 10% AA aqueous solution, which is better than in water. The removal rate of SMR in the AA solution decreased as the initial molar ratio of SMR and O-3 increased. The removal rate of SMR decreased with Fe3+ present in the reactive system. The removal of SMR is dominated by indirect ozonation in water, while the SMR removal is an effect of both direct and indirect ozonation in AA solution. It is a very efficient process for the degradation of SMR in micro polluted water when using combined GAC adsorption-desorption in AA solution and ozonation of the resulting solution.
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    Simulating PFAS adsorption kinetics, adsorption isotherms, and nonideal transport in saturated soil with tempered one-sided stable density (TOSD) based models
    (Elsevier, 2021) Zhou, Dongbao; Brusseau, Mark L.; Zhang, Yong; Li, Shiyin; Wei, Wei; Sun, HongGuang; Zheng, Chunmiao; Hohai University; University of Arizona; University of Alabama Tuscaloosa; Nanjing Normal University; Southern University of Science & Technology
    Reliable quantification of per- and polyfluoroalkyl substances (PFAS) adsorption and mobility in geomedia provides critical information (i.e., evaluation and prediction) for risk characterization and mitigation strategy development. Given the limited PFAS data available and various competing theories for modeling pollutant kinetics, it is indispensable to better understand and quantify the adsorption and transport of PFAS in geomedia using generalized models built upon a consistent physical theory. This study proposed a universal physical law (called the tempered stable law) in PFAS adsorption/transport by interpreting PFAS adsorption kinetics and nonideal transport as a nonequilibrium process dominated by adsorption/desorption with multiple rates following the tempered one-sided stable density (TOSD) distribution. This universal TOSD function led to novel TOSD-based models which were then tested by successfully simulating PFAS adsorption kinetics, adsorption isotherms, and nonideal transport data reported in the literature. Model comparisons and extensions were also discussed to further check the feasibility of the TOSD models and their adaptability to capture PFAS transport in more complex geomedia at all scales.
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    Stability of Chloropyromorphite in Ryegrass Rhizosphere as Affected by Root-Secreted Low Molecular Weight Organic Acids
    (PLOS, 2016) Wei, Wei; Wang, Yu; Wang, Zheng; Han, Ruiming; Li, Shiyin; Wei, Zhenggui; Zhang, Yong; Nanjing Normal University; Anqing Normal University; University of Alabama Tuscaloosa
    Understanding the stability of chloropyromorphite (CPY) is of considerable benefit for improving risk assessment and remediation strategies in contaminated water and soil. The stability of CPY in the rhizosphere of phosphorus-deficient ryegrass was evaluated to elucidate the role of root-secreted low molecular weight organic acids (LMWOAs) on the dissolution of CPY. Results showed that CPY treatments significantly reduced the ryegrass biomass and rhizosphere pH. The presence of calcium nitrate extractable lead (Pb) and phosphorus (P) suggested that CPY in the rhizosphere could be bioavailable, because P and Pb uptake by ryegrass potentially provided a significant concentration gradient that would promote CPY dissolution. Pb accumulation and translocation in ryegrass was found to be significantly higher in P-sufficient conditions than in P-deficient conditions. CPY treatments significantly enhanced root exudation of LMWOAs irrigated with P-nutrient solution or P-free nutrient solution. Oxalic acid was the dominant species in root-secreted LMWOAs of ryegrass under P-free nutrient solution treatments, suggesting that root-secreted oxalic acid may be the driving force of root-induced dissolution of CPY. Hence, our work, provides clarifying hints on the role of LMWOAs in controlling the stability of CPY in the rhizosphere.