Showing papers by "Xiaolei Qu published in 2017"
TL;DR: Gold ion (Au3+) was used as a model heavy metal ion to quantitatively assess the role of EPS in biomineralization and discern the responsible functional groups, indicating a previously overlooked, universally significant contribution of EPS to the reduction, mineralization, and potential detoxification of metal species with high oxidation state.
Abstract: Biomineralization is a critical process controlling the biogeochemical cycling, fate, and potential environmental impacts of heavy metals. Despite the indispensability of extracellular polymeric substances (EPS) to microbial life and their ubiquity in soil and aquatic environments, the role played by EPS in the transformation and biomineralization of heavy metals is not well understood. Here, we used gold ion (Au3+) as a model heavy metal ion to quantitatively assess the role of EPS in biomineralization and discern the responsible functional groups. Integrated spectroscopic analyses showed that Au3+was readily reduced to zerovalent gold nanoparticles (AuNPs, 2–15 nm in size) in aqueous suspension of Escherichia coli or dissolved EPS extracted from microbes. The majority of AuNPs (95.2%) was formed outside Escherichia coli cells, and the removal of EPS attached to cells pronouncedly suppressed Au3+ reduction, reflecting the predominance of the extracellular matrix in Au3+ reduction. XPS, UV–vis, and FTIR a...
147 citations
TL;DR: The results infer that there is a vertical mass flux of DBC and possible fractionation from the dissolved organic matter pool in the fluvial and estuarine systems, which have been overlooked in efforts to determine global carbon budgets and associated climate change implications.
Abstract: The fluvial export of dissolved black carbon (DBC) is a major land-ocean flux in the global black carbon cycle, affecting the size of refractory carbon pool in the oceans. The aggregation behavior of DBC is a significant determinant of its transport and vertical mass flux. In this study, the aggregation kinetics and interaction energy of DBC leached from biochar were investigated. DBC was mainly stabilized by hydration force and underwent structural compacting in divalent cation solutions. Na+ and Mg2+ had limited impact on the colloidal stability of DBC due to the strong hydration of these cations. Ca2+ and Ba2+ readily destabilized DBC by forming inner-sphere complexes, reducing its hydrophilicity. Consistently, charge reversal of DBC was observed with high concentrations of Ca2+ and Ba2+. Simulated sunlight exposure led to photo-oxidation of DBC, increasing its colloidal stability. DBC behaved nonconservatively in laboratory mixing experiments using estuary water samples due to aggregation/sedimentatio...
85 citations
TL;DR: In this paper, bimetallic Au@Pd/TiO 2 catalysts with an Au loading amount of 0.94% were prepared using a two-step photocatalytic deposition method, and the solvent-free aerobic oxidation of benzyl alcohol was investigated on the catalysts.
72 citations
TL;DR: Findings indicated an important and previously unrecognized role of LPyOC (i.e., micropore clogging) in the nonideal sorption of organic contaminants to BC.
50 citations
TL;DR: The results clearly demonstrate that phospholipid extraction by MWCNTs could occur in electrostatically repulsive conditions, and M WCNT defects were active binding sites whether or not they were oxygenated.
47 citations
TL;DR: It is underscores the importance to account for photochemical effects to inform risk assessments and regulations of cadmium pigments which are currently based on their low solubility.
Abstract: Cadmium pigments are widely used in the polymer and ceramic industry. Their potential environmental risk is under debate, being the major barrier for appropriate regulation. We show that 83.0 ± 0.2% of hazardous cadmium ion (Cd2+) was released from the commercial cadmium sulfoselenide pigment (i.e., cadmium red) in aqueous suspension within 24 h under simulated sunlit conditions. This photodissolution process also generated sub-20 nm pigment nanoparticles. Cd2+ release is attributed to the reactions between photogenerated holes and the pigment lattices. The photodissolution process can be activated by both ultraviolet and visible light in the solar spectrum. Irradiation under alkaline conditions or in the presence of phosphate and carbonate species resulted in reduced charge carrier energy or the formation of insoluble and photostable cadmium precipitates on pigment surfaces, mitigating photodissolution. Tannic acid inhibited the photodissolution process by light screening and scavenging photogenerated ho...
36 citations
TL;DR: Distinguishing the role of bound and unbound HA in the aggregation and deposition of carbon nanomaterials is important to predict their transport in various natural waters.
19 citations
Patent•
16 Jun 2017
TL;DR: In this article, a method for removing thio-alcohol taste andodor compounds in a water body by using copper-modified molecular sieve particles was proposed, which can adsorb and remove thio alcohol taste and odour compounds in water.
Abstract: The invention discloses application of copper-modified molecular sieve particles to removal of thio-alcohol taste-and-odor compounds in a water body. The invention discloses a method for removing thio-alcohol taste-and-odor compounds in a water body by using copper-modified molecular sieve particles. The copper-modified molecular sieve particles can adsorb and remove thio-alcohol taste-and-odor compounds in water under the condition of a pH value of 4 to 8, wherein adsorption time is 30 min to 24 h, and temperature is 293 to 303 K. According to the invention, the copper-modified molecular sieve particles are used for adsorbing and removing thio-alcohol taste-and-odor compounds in water and present good adsorption performance; the copper-modified molecular sieve particles are simple to prepare, convenient to operate, low in cost, substantial in treatment effect and recyclable; thus, good economic and environmental benefits are obtained when the copper-modified molecular sieve particles are used for removing thio-alcohol taste-and-odor compounds in contaminated water bodies.
1 citations
Patent•
25 Jan 2017
TL;DR: In this paper, a method for removing 1-butyl-3-methylimidazol ionic liquid pollutants out water by using a nitric acid oxidized ordered mesoporous carbon material CMK-3 is presented.
Abstract: The invention discloses a method for removing 1-butyl-3-methylimidazol ionic liquid pollutants out water by using a nitric acid oxidized ordered mesoporous carbon material CMK-3. The method comprises the following steps: firstly, adding an ordered mesoporous carbon material CMK-3 into a nitric acid aqueous solution, and performing heating reaction to obtain the nitric acid oxidized ordered mesoporous carbon material CMK-3; adding the prepared CMK-3 into a polluted aqueous solution containing 1-butyl-3-methylimidazol ionic liquid, performing oscillation adsorption, and filtering to remove the nitric acid oxidized ordered mesoporous carbon material CMK-3 with adsorbed ionic liquid; and finally, regenerating an adsorbent by using hydrochloric acid. By virtue of simple nitric acid oxidation treatment, rich surface functional groups mainly including carboxyl groups are loaded on the surface of the ordered mesoporous carbon material, so that a high specific area of the mesoporous carbon material is ensured, a large amount of oxygen-containing functional groups are loaded on the surface of the material, and 1-butyl-3-methylimidazol ionic liquid can be effectively separated through adsorption.
1 citations