Nanoscale zero-valent iron for metal/metalloid removal from model hydraulic fracturing wastewater

Sun, Yuqing,Lei, Cheng,Khan, Eakalak,Chen, Season S.,Tsang, Daniel C.W.,Ok, Yong Sik,Lin, Daohui,Feng, Yujie,Li, Xiang-dong Elsevier 2017 CHEMOSPHERE - Vol.176 No.-

<P><B>Abstract</B></P> <P>Nanoscale zero-valent iron (nZVI) was tested for the removal of Cu(II), Zn(II), Cr(VI), and As(V) in model saline wastewaters from hydraulic fracturing. Increasing ionic strength (<I>I</I>) from 0.35 to 4.10 M (Day-1 to Day-90 wastewaters) increased Cu(II) removal (25.4–80.0%), inhibited Zn(II) removal (58.7–42.9%), slightly increased and then reduced Cr(VI) removal (65.7–44.1%), and almost unaffected As(V) removal (66.7–75.1%) by 8-h reaction with nZVI at 1–2 g L<SUP>−1</SUP>. The removal kinetics conformed to pseudo-second-order model, and increasing <I>I</I> decreased the surface area-normalized rate coefficient (<I>k</I> <SUB> <I>sa</I> </SUB>) of Cu(II) and Cr(VI), probably because agglomeration of nZVI in saline wastewaters restricted diffusion of metal(loid)s to active surface sites. Increasing <I>I</I> induced severe Fe dissolution from 0.37 to 0.77% in DIW to 4.87–13.0% in Day-90 wastewater; and Fe dissolution showed a significant positive correlation with Cu(II) removal. With surface stabilization by alginate and polyvinyl alcohol, the performance of entrapped nZVI in Day-90 wastewater was improved for Zn(II) and Cr(VI), and Fe dissolution was restrained (3.20–7.36%). The X-ray spectroscopic analysis and chemical speciation modelling demonstrated that the difference in removal trends from Day-1 to Day-90 wastewaters was attributed to: (i) distinctive removal mechanisms of Cu(II) and Cr(VI) (adsorption, (co-)precipitation, and reduction), compared to Zn(II) (adsorption) and As(V) (bidentate inner-sphere complexation); and (ii) changes in solution speciation (e.g., from Zn<SUP>2+</SUP> to ZnCl<SUB>3</SUB> <SUP>−</SUP> and ZnCl<SUB>4</SUB> <SUP>2−</SUP>; from CrO<SUB>4</SUB> <SUP>2−</SUP> to CaCrO<SUB>4</SUB> complex). Bare nZVI was susceptible to variations in wastewater chemistry while entrapped nZVI was more stable and environmentally benign, which could be used to remove metals/metalloids before subsequent treatment for reuse/disposal.</P> <P><B>Highlights</B></P> <P> <UL> <LI> nZVI could remove Cu(II), Zn(II), Cr(VI), and As(V) from fracturing wastewaters. </LI> <LI> High salinity enhanced Fe dissolution and reduced removal rates except Cu(II). </LI> <LI> nZVI entrapment mitigated Fe dissolution and improved metal(loid) removal. </LI> <LI> Removal efficiency varied with interaction mechanisms and solution speciation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Zero-valent iron for the abatement of arsenate and selenate from flowback water of hydraulic fracturing

Sun, Yuqing,Chen, Season S.,Tsang, Daniel C.W.,Graham, Nigel J.D.,Ok, Yong Sik,Feng, Yujie,Li, Xiang-Dong Elsevier 2017 CHEMOSPHERE - Vol.167 No.-

<P><B>Abstract</B></P> <P>Zero-valent iron (ZVI) was tested for the removal of 150 μg L<SUP>−1</SUP> As(V) and 350 μg L<SUP>−1</SUP> Se(VI) in high-salinity (ionic strength 0.35–4.10 M) flowback water of hydraulic fracturing. Over 90% As(V) and Se(VI) was removed by 2.5 g L<SUP>−1</SUP> ZVI in Day-14 flowback water up to 96-h reaction, with the remaining concentration below the maximum contaminant level for As(V) and criterion continuous concentration for Se(VI) recommended by US EPA. The kinetics of As(V) and Se(VI) removal followed a pseudo-second-order rate expression with the observed rates of 4.51 × 10<SUP>−2</SUP>–4.91 × 10<SUP>−1</SUP> and 3.48 × 10<SUP>−2</SUP>–6.58 × 10<SUP>−1</SUP> h<SUP>−1</SUP> (with 0.5–10 g L<SUP>−1</SUP> ZVI), respectively. The results showed that Se(VI) removal significantly decreased with increasing ionic strength, while As(V) removal showed little variation. Common competing anions (nitrate, bicarbonate, silicate, and phosphate), present in shallow groundwater and stormwater, caused marginal Se(VI) desorption (2.42 ± 0.13%) and undetectable As(V) desorption from ZVI. The competition between As(V) and Se(VI) for ZVI removal depended on the initial molar ratio and surface sites, which occurred when the Se(VI) concentration was higher than the As(V) concentration in this study. The characterization of As(V)- and Se(VI)-loaded ZVI by X-ray diffraction and Raman analysis revealed that ZVI gradually converted to magnetite/maghemite corrosion products with lepidocrocite in flowback water over 30 days. Similar corrosion compositions were confirmed in aerobic and anaerobic conditions regardless of the molar ratio of As(V) to Se(VI). The high reactivity and stability of ZVI showed its suitability for <I>in-situ</I> prevention of As(V) and Se(VI) migration due to accidental leakage, spillage, or overflow of flowback water.</P> <P><B>Highlights</B></P> <P> <UL> <LI> As(V) and Se(VI) in high-salinity flowback water was effectively removed by ZVI. </LI> <LI> As(V) removal was less susceptible to ionic strength variations than Se(V). </LI> <LI> Competing anions in groundwater and stormwater caused insignificant desorption. </LI> <LI> As(V) and Se(VI) competition depended on their molar ratio and ZVI surface sites. </LI> <LI> Surface characteristics of ZVI were unaffected by molar ratio and dissolved oxygen. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Aging effects on chemical transformation and metal(loid) removal by entrapped nanoscale zero-valent iron for hydraulic fracturing wastewater treatment

Sun, Yuqing,Lei, Cheng,Khan, Eakalak,Chen, Season S.,Tsang, Daniel C.W.,Ok, Yong Sik,Lin, Daohui,Feng, Yujie,Li, Xiang-dong Elsevier 2018 Science of the Total Environment Vol.615 No.-

<P><B>Abstract</B></P> <P>In this study, alginate and polyvinyl alcohol (PVA)-alginate entrapped nanoscale zero-valent iron (nZVI) was tested for structural evolution, chemical transformation, and metals/metalloids removal (Cu(II), Cr(VI), Zn(II), and As(V)) after 1–2month passivation in model saline wastewaters from hydraulic fracturing. X-ray diffraction analysis confirmed successful prevention of Fe<SUP>0</SUP> corrosion by polymeric entrapment. Increasing ionic strength (<I>I</I>) from 0 to 4.10M (deionized water to Day-90 fracturing wastewater (FWW)) with prolonged aging time induced chemical instability of alginate due to dissociation of carboxyl groups and competition for hydrogen bonding with nZVI, which caused high Na (7.17%) and total organic carbon (24.6%) dissolution from PVA-alginate entrapped nZVI after 2-month immersion in Day-90 FWW. Compared to freshly-made beads, 2-month aging of PVA-alginate entrapped nZVI in Day-90 FWW promoted Cu(II) and Cr(VI) uptake in terms of the highest removal efficiency (84.2% and 70.8%), pseudo-second-order surface area-normalized rate coefficient <I>k</I> <SUB> <I>sa</I> </SUB> (2.09×10<SUP>−1</SUP> Lm<SUP>−2</SUP> h<SUP>−1</SUP> and 1.84×10<SUP>−1</SUP> Lm<SUP>−2</SUP> h<SUP>−1</SUP>), and Fe dissolution after 8-h reaction (13.9% and 8.45%). However, the same conditions inhibited Zn(II) and As(V) sequestration in terms of the lowest removal efficiency (31.2% and 39.8%) by PVA-alginate nZVI and <I>k</I> <SUB> <I>sa</I> </SUB> (4.74×10<SUP>−2</SUP> Lm<SUP>−2</SUP> h<SUP>−1</SUP> and 6.15×10<SUP>−2</SUP> Lm<SUP>−2</SUP> h<SUP>−1</SUP>) by alginate nZVI. The X-ray spectroscopic analysis and chemical speciation modelling demonstrated that the difference in metals/metalloids removal by entrapped nZVI after aging was attributed to distinctive removal mechanisms: (i) enhanced Cu(II) and Cr(VI) removal by nZVI reduction with accelerated electron transfer after pronounced dissolution of non-conductive polymeric immobilization matrix; (ii) suppressed Zn(II) and As(V) removal by nZVI adsorption due to restrained mass transfer after blockage of surface-active micropores. Entrapped nZVI was chemically fragile and should be properly stored and regularly replaced for good performance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> nZVI entrapment successfully prevented Fe<SUP>0</SUP> corrosion in fracturing wastewaters. </LI> <LI> Entrapped nZVI was chemically fragile due to dissolution of Na and TOC. </LI> <LI> nZVI passivation promoted Cu(II) and Cr(VI) but inhibited Zn(II) and As(V) removal. </LI> <LI> Effects of nZVI aging on removal efficiency depended on interaction mechanisms. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Microstructure and property evolution of diamond-like carbon films co-doped by Al and Ti with different ratios

Zhou, Yong,Guo, Peng,Sun, Lili,Liu, Linlin,Xu, Xiaowei,Li, Wenxian,Li, Xiaowei,Lee, Kwang-Ryeol,Wang, Aiying Elsevier Sequoia 2019 Surface & coatings technology Vol.361 No.-

<P><B>Abstract</B></P> <P>Diamond-like carbon (DLC) films with weak carbide metal Al and carbide metal Ti co-doping (Al/Ti-DLC) were prepared by a hybrid ion beam deposition system. The atomic ratios of doped Al to Ti were tailored via designing the special Al/Ti combined sputtering target. The composition, microstructure, roughness, residual stress, hardness, toughness, and tribological behaviors of the deposited films were systematically evaluated to explore the dependence of structural properties on Al/Ti ratios. Results indicated that the high-throughput preparation of DLC films with different Al/Ti atomic ratios was achieved by tailoring the sputtering target and process parameters without the difference in both the film thickness and total Al/Ti content. With the Al/Ti ratios in the films decreased from 8.8 to 3.0, the residual stress, hardness, and toughness of Al/Ti-DLC films increased obviously, originating from the increased fraction of titanium carbide and the reduced Al content. However, the coefficient of friction and wear rate with decreasing the Al/Ti ratio were obviously improved, which was related with the transformation of underlying friction mechanism from the sliding interface graphitization to dangling bond-passivation. The present results not only suggest a high-throughput method to fabricate co-doped DLC films, but also promote the scientific understanding and engineering application of DLC films with high performance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ti/Al co-doped diamond-like carbon films were fabricated by a hybrid ion beam method. </LI> <LI> Different Al/Ti ratios were successfully achieved at one time using designed target. </LI> <LI> Al/Ti ratios had no effect on the chemical state of co-doped Ti and Al atoms. </LI> <LI> The mechanical and tribological properties were strongly dependent on Ti/Al ratios. </LI> <LI> Different friction mechanisms were observed with Al/Ti ratios ranged from 8.8 to 3.0. </LI> </UL> </P>

Insights into the subsurface transport of As(V) and Se(VI) in produced water from hydraulic fracturing using soil samples from Qingshankou Formation, Songliao Basin, China

Chen, Season S.,Sun, Yuqing,Tsang, Daniel C.W.,Graham, Nigel J.D.,Ok, Yong Sik,Feng, Yujie,Li, Xiang-Dong Elsevier 2017 Environmental pollution Vol.223 No.-

<P><B>Abstract</B></P> <P>Produced water is a type of wastewater generated from hydraulic fracturing, which may pose a risk to the environment and humans due to its high ionic strength and the presence of elevated concentrations of metals/metalloids that exceed maximum contamination levels. The mobilization of As(V) and Se(VI) in produced water and selected soils from Qingshankou Formation in the Songliao Basin in China were investigated using column experiments and synthetic produced water whose quality was representative of waters arising at different times after well creation. Temporal effects of produced water on metal/metalloid transport and sorption/desorption were investigated by using HYDRUS-1D transport modelling. Rapid breakthrough and long tailings of As(V) and Se(VI) transport were observed in Day 1 and Day 14 solutions, but were reduced in Day 90 solution probably due to the elevated ionic strength. The influence of produced water on the hydrogeological conditions (i.e., change between equilibrium and non-equilibrium transport) was evidenced by the change of tracer breakthrough curves before and after the leaching of produced water. This possibly resulted from the sorption of polyacrylamide (PAM (-CH<SUB>2</SUB>CHCONH<SUB>2</SUB>-)<SUB>n</SUB>) onto soil surfaces, through its use as a friction reducer in fracturing solutions. The sorption was found to be reversible in this study. Minimal amounts of sorbed As(V) were desorbed whereas the majority of sorbed Se(VI) was readily leached out, to an extent which varied with the composition of the produced water. These results showed that the mobilization of As(V) and Se(VI) in soil largely depended on the solution pH and ionic strength. Understanding the differences in metal/metalloid transport in produced water is important for proper risk management.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Earlier breakthrough of metals with increasing ionic strength of flowback solutions. </LI> <LI> Two-region physical non-equilibrium model provided a good fit of metal transport. </LI> <LI> Less non-equilibrium transport in Day 14 and Day 90 than Day 1 flowback solutions. </LI> <LI> Tracer tests indicated reversible change of transport channels due to leaching. </LI> <LI> Sorption/desorption of As(V) and Se(VI) was both pH- and ionic strength-dependent. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Disturbance Rejection of Superheated Steam Temperature in a Utility Boiler

Li Sun,Donghai Li,Yong Sun,Yali Xue,Kwang Y. Lee 제어로봇시스템학회 2016 제어로봇시스템학회 국제학술대회 논문집 Vol.2016 No.10

This paper derived a model for the superheated steam temperature based on the open-loop step response. A cascaded control structure based on disturbance observer (DOB) is proposed to accommodate the control difficulties. The simulation results show the great performance improvement compared with the conventional cascaded control structure. This paper is a preliminary research to the cascaded DOB control structure. Much improvement, theoretic analysis and experimental demonstration will be carried out in the future.

Parthenolide-Induced Apoptosis, Autophagy and Suppression of Proliferation in HepG2 Cells

Sun, Jing,Zhang, Chan,Bao, Yong-Li,Wu, Yin,Chen, Zhong-Liang,Yu, Chun-Lei,Huang, Yan-Xin,Sun, Ying,Zheng, Li-Hua,Wang, Xue,Li, Yu-Xin Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.12

Purpose: To investigate the anticancer effects and underlying mechanisms of parthenolide on HepG2 human hepatocellular carcinoma cells. Materials and Methods: Cell viability was assessed by MTT assay and cell apoptosis through DAPI, TUNEL staining and Western blotting. Monodansylcadaverin(MDC) and AO staining were used to detect cell autophagy. Cell proliferation was assessed by Ki67 immunofluorescence staining. Results: Parthenolide induced growth inhibition in HepG2 cells. DAPI and TUNEL staining showed that parthenolide could increase the number of apoptotic nuclei, while reducing the expression of the anti-apoptotic protein Bcl-2 and elevating the expression of related proteins, like p53, Bax, cleaved caspase9 and cleaved caspase3. Parthenolide could induce autophagy in HepG2 cells and inhibited the expression of proliferation-related gene, Ki-67. Conclusions: Parthenolide can exert anti-cancer effects by inducing cell apoptosis, activating autophagy and inhibiting cell proliferation.

Purification and Characterization of Cathepsin B from the Gut of the Sea Cucumber (Stichopus japonicas)

Li-Ming Sun,Bei-Wei Zhu,Hai-tao Wu,Lei Yu,Da-Yong Zhou,Xiuping Dong,Jing-Feng Yang,Dong-Mei Li,Wen-Xiu Ye,Yoshiyuki Murata 한국식품과학회 2011 Food Science and Biotechnology Vol.20 No.4

Cathepsin B from the gut of sea cucumber (Stichopus japonicas) was purified 81-fold with a 3%recovery by ammonium sulfate fractionation and a series chromatography on DEAE Sepharose CL-6B, Sephadex G-75, and TSK-Gel 3000 SWxl. The purified protein appeared as a single band on Native-PAGE but showed 2bands of 23 and 26 kDa on SDS-PAGE. The optimum activity was found at pH 5.5 and 45°C. The enzyme was stable at pH 4.5-6.0 and the thermal stability was up to 50oC. The enzyme was strongly inhibited by E-64, iodoacetic acid, and antipain, demonstrating it is a cysteine protease containing sulfhydryl groups. Cu^2+, Ni^2+, and Zn^2+ could strongly inhibit the enzyme activity. The amino acid sequences of the purified enzyme were acquired by mass spectrometer, which did not show any homology with previously described cathepsins, suggesting it may be a novel member.

Intermedins A and B; New Metabolites from Schisandra propinqua var. intermedia

Li, Hong-Mei,Lei, Chun,Luo, Yong-Ming,Li, Xiao-Nian,Li, Xiao-Lei,Pu, Jian-Xin,Zhou, San-Yun,Li, Rong-Tao,Sun, Han-Dong 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.6

A new dibenzocyclooctadiene lignan, intermedin A (1), and a new natural bisabolane sesquiterpenoid, intermedin B (2), were isolated from the aerial parts of Schisandra propinqua var. intermedia. Their structures were elucidated on the basis of extensive spectroscopical analysis.

The novel microtubule-associated CAP-glycine protein Cgp1 governs growth, differentiation, and virulence of <i>Cryptococcus neoformans</i>

Wang, Li Li,Lee, Kyung-Tae,Jung, Kwang-Woo,Lee, Dong-Gi,Bahn, Yong-Sun TaylorFrancis 2018 Virulence Vol.9 No.1

<P><B>ABSTRACT</B></P><P>Microtubules are involved in mechanical support, cytoplasmic organization, and several cellular processes by interacting with diverse microtubule-associated proteins such as plus-end tracking proteins, motor proteins, and tubulin-folding cofactors. A number of the cytoskeleton-associated proteins (CAPs) contain the CAP-glycine-rich (CAP-Gly) domain, which is evolutionarily conserved and generally considered to bind to α-tubulin to regulate the function of microtubules. However, there has been a dearth of research on CAP-Gly proteins in fungal pathogens, including <I>Cryptococcus neoformans</I>, which is a global cause of fatal meningoencephalitis in immunocompromised patients. In this study, we identified five CAP-Gly protein-encoding genes in <I>C. neoformans</I>. Among these, Cgp1 encoded by CNAG_06352 has a unique domain structure containing CAP-Gly, SPEC, and Spc7 domains that is not orthologous to CAPs in other eukaryotes. Supporting the role of Cgp1 in microtubule-related function, we demonstrate that deletion or overexpression of <I>CGP1</I> alters cellular susceptibility to thiabendazole, a microtubule destabilizer and that Cgp1 is co-localized with cytoplasmic microtubules. Related to the cellular function of microtubules, Cgp1 governs the maintenance of membrane stability and genotoxic stress responses. Deletion of <I>CGP1</I> also reduces production of melanin pigment and attenuates the virulence of <I>C. neoformans</I>. Furthermore, we demonstrate that Cgp1 uniquely regulates the sexual differentiation of <I>C. neoformans</I> with distinct roles in the early and late stage of mating. Domain analysis revealed that the CAP-Gly domain plays a major role in all Cgp1 functions examined. In conclusion, this novel CAP-Gly protein, Cgp1, has pleotropic roles in regulating growth, stress responses, differentiation, and virulence in <I>C. neoformans</I>.</P>