SCIENCE OF THE TOTAL ENVIRONMENT
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2020
·
IF 6.551
Nan Xu,Zuling Li,Xinxing Huangfu,Xueying Cheng,Christos Christodoulatos,Junchao Qian,Ming Chen,Jianping Chen,Chunming Su,Dengjun Wang
The soil major component of clay plays an important role in governing the fate and transport of engineered nanomaterials (e.g., the most commonly used titanium dioxide nanoparticles ; nTiO 2 ) in the subsurface environments via forming nTiO 2 -clay aggregates. This research is designed to unravel the interplay of naturally-occurring bacteria ( Escherichia coli ) and phosphate on the transport and retention of nTiO 2 -kaolin aggregates in water-saturated porous media . Our results showed that nTiO 2 -nTiO 2 homoaggregates and nTiO 2 -kaolin heteroaggregates dominated in the nTiO 2 -kaolin nanoaggregate suspension. Transport of nTiO 2 -kaolin aggregates was enhanced with the copresence of E. coli and phosphate, particularly at the low pH of 6.0. This effect is due to the greater adsorption of phosphate and thus the greater enhancement in repulsive interaction energies between aggregates and sand grains at pH 6.0 (vs. pH 9.0). The charged “soft layer” of E. coli cell surfaces changed the aggregation state and the heterogeneous distribution of nTiO 2 -kaolin aggregates, and subsequently stabilized the nTiO 2 -nTiO 2 homoaggregates and nTiO 2 -kaolin heteroaggregates via TEM-EDX measurements and promoted the physical segregation between the aggregates (separation distance = 0.486 vs. 0.614 μm without vs. with the presence of E. coli ) via 2D/3D AFM identifications, both of which caused greater mobility of nTiO 2 -kaolin aggregates with the presence of E. coli . Nonetheless, transport of nTiO 2 -kaolin aggregates was lower with the copresence of E. coli and phosphate vs. the singular presence of phosphate due to the competitive adsorption of less negatively charged E. coli (vs. phosphate) onto the aggregates. Taken altogether, our findings furnish new insights into better understanding the fate, transport, and potential risks of nTiO 2 in real environmental settings (soil and sediment aquifer) where clay, bacteria, and phosphate ubiquitously cooccur.
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高影响因子
CARBON
·
2019
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IF 7.466
Sishi Long,Yunchao Feng,Faliang He,Shuaishuai He,Huachi Hong,Xuerui Yang,Lingling Zheng,Jian Liu,Lihui Gan,Minnan Long
Compressible and ultralight carbon aerogels are attractive due to its compressibility , elasticity and conductivity. However, it is still a great challenge to enrich the properties of carbon aerogel to meet various requirements. Herein, we report an untralight, supercompressible, fatigue resistant, superhydrophobic and fire-resistant and multifunctional CNF-GO/glucose-kaolin carbon aerogel (C-NGGK) carbon aerogel. To achieve such excellent performances, calcined GO , CNFs , glucose and kaolin are used for forming low-density and continuous wave-shape rGO layers, reinforcing the mechanical strength of carbon layers , realizing superelasticity and fatigue resistance and resulting in a superhydrophobic surface for C-NGGK, respectively. The as-prepared C-NGGK demonstrates excellent superhydrophobicity with the water contact angle (WCA) of 124.9°, and the absorption efficiency of the C-NGGK samples for different oils and organic solvents are 75–255 times their own weight. These advantages show that the C-NGGK can be an ideal candidate for oil/water separation. In addition, there is also the prospect to be used for pressure sensors , while other potential applications include three-dimensional electrode materials for supercapacitors and batteries , catalyst carriers and various wearable devices .
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高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2019
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IF 4.784
Tao Zeng,Xue-qin Hu,Hao Wu,Jing-wen Yang,Hong-bin Zhang
Polysaccharide-modified flocculants as natural polymeric flocculants are receiving increased attention in the field of water treatment. In this study, a novel high-efficiency and ecofriendly flocculant was synthesized using dextran and chitosan. The flocculant-production method was based on a microwave-heating-initiated graft reaction. Results of Fourier transform infrared spectroscopy, nuclear magnetic resonance imaging, X-ray diffraction, elemental analysis, thermogravimetric analysis, and field-emission scanning electron microscopy confirmed that the grafting was successful. The influences of temperature, flocculant dosage, and pH on flocculation efficiency were investigated. Results indicated that 93.6% of the kaolin solid suspended particles were removed by the flocculant. Previous studies on the flocculation mechanism have shown that flocculation comprises adsorption bridging, charge neutralization, and sweeping flocculation. All these findings indicated the broad prospects of the improved dextran in treating industrial wastewater and developing novel high-performance flocculants.
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高影响因子
ACS Sustainable Chemistry & Engineering
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2019
·
IF 6.97
Mei-Li Song,Hou-Yong Yu,Lu-Min Chen,Jia-Ying Zhu,Yan-Yan Wang,Ju-Ming Yao,Zhuanyong Zou,Kam Chiu Tam
A simple multibranch strategy was employed to increase the carboxyl contents on the cellulose nanocrystal (CNC) surface. The effects of various sequential grafting of ascorbic acid or citric acid on the morphology, microstructure, thermal stability, dye adsorption capability (methylene blue), and coagulation–flocculation capacity (model kaolin suspension) of the functionalized CNCs were investigated. Cellulose nanocrystals with multicarboxyl groups (CNC-g-AA-g-CA) showed better thermal stability (Tmax = 359.3 °C), and possessed the highest carboxylic groups of 4.073 mmol/g, which led to a high absolute ζ potential value up to 47.7 mV. Furthermore, the CNC-g-AA-g-CA exhibited excellent coagulation–flocculation capability to kaolin suspension with a turbidity removal rate of 91.07% and good cationic dye (methylene blue) removal rate of 87.8%, indicating that the CNC-g-AA-g-CA can be used as excellent adsorbent and efficient flocculants. In addition, CNC-g-AA-g-CA have good stabilizing effects on soybean oil/water Pickering emulsions, and the resultant Pickering emulsion volume can remain for 30 days or longer.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2019
·Vol. 26
·期 28
·28898-28908
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IF 2.914
Zhang Yakun,Chen Sisi,Feng Xuezhen,Yu Jingang,Jiang Xinyu
The assembly of graphene oxide with biomass or polymers to form 3D hydrogels with excellent mechanical properties has become a research hotspot. In this work, the sponge-like kaolin/chitosan (CS)/reduced graphene oxide (rGO) composite was prepared for adsorption by simple self-assembly without cross-linking agent. The morphology, composition, surface properties, and pore size of as-prepared materials were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), zeta potential analyzer, Brunauer-Emmett-Teller surface area measurement (BET), and scanning electron microscopy (SEM). The effects of raw material ratio, contact time, temperature, pH, ionic strength, and recycling times on adsorption performance were investigated in detail. The results indicate that the composite has good absorption capacity for Cr(VI) and alizarin yellow R (AYR). Besides, composite hydrogel also exhibits excellent flexibility and good repeatability, which confirms its great potential as an adsorbent to remove pollutants in the water environment.
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高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2019
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IF 7.015
Hui Jia,Fangfang Feng,Jie Wang,Huu-Hao Ngo,Wenshan Guo,Hongwei Zhang
The hollow fiber ultrafiltration (UF) membrane has been widely applied in the water treatment industry, however, the membrane fouling is the core reason and limiting factor in terms of its industrial application. In the constant flux process, hollow fiber membranes (HFM) non-uniform fouling varies along the axis direction, which is the basic mechanism of HFM fouling. In this paper, the local membrane fouling behaviors and verities are investigated using electrical impedance (EI) and zeta potential (ZP) to capture the feedback signals of membrane fouling behaviors. The results are then, integrated with Hermia's model and an equivalent circuit model. As the fitting results show, both the EI and ZP can be employed as indicators of different membrane fouling states. This work defines the different stages of membrane fouling depending on the alternating relationship between EI and ZP in the membrane filtration process. Furthermore, the behavior of cake layer compaction is defined from the perspective of the membrane fouling mechanism. Therefore, this study provides an effective means for accurate identification of membrane fouling behavior. In addition, the EI and ZP exhibit great potential to identify the fouling distributions and proceedings in HFM fouling. Doing so successfully confirms that the characteristics of non-uniform fouling of HFM are reflected in the spatiotemporal difference of the fouling process.
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Journal of Environmental Chemical Engineering
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2019
·
IF 0
Jie Ma,Runnan Wang,Xiyue Wang,Hao Zhang,Bo Zhu,Lili Lian,Dawei Lou
In the current work, polysilicate aluminum magnesium (PSAM) and cationic polyacrylamide (cPAM) were stepwise used for drinking water treatment . The flocculant was characterized by fourier transform infrared spectroscopy , scanning electron microscopy, and energy dispersive spectroscopy. PSAM-cPAM was then applied to flocculate the simulated water sample. The simulated water sample was prepared by kaolin and sodium humate. The efficiency of flocculation treatment was highly dependent on the flocculation conditions. Important parameters, such as the pH value of simulated water sample, temperature, settling time, the total dosage of flocculant, and flocculant types, were optimized to ensure an effective flocculation performance. Under optimized conditions, the removal efficiency (more than 98%) was outstanding in terms of turbidity and color removal. In addition, charge neutralization, bridging effect, and co–precipitation interaction could play crucial roles in the flocculation process. Composite flocculants consisting of PSAM and cPAM were found to be environmentally friendly, highly efficient, and fast settling in drinking water treatment.
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Arabian Journal of Chemistry
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2020
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IF 4.762
Zefeng Yu,Weifeng Song,Jiayao Li,Qiuhua Li
In this paper, a metakaolin-based mesoporous geopolymer (GP-CTAB) was used as adsorbent for Cu(II) and Cr(VI) through a novel and simple synthetic route using cetyltrimethylammonium bromide (CTAB) as an organic modifier. The application of GP-CTAB for the simultaneous removal of metal anions and cations in aqueous solution was studied for the first time. The results of X-ray diffraction (XRD) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Brunauer, Emmett and Teller (BET), and Barrett, Joyner, and Halenda (BJH) methods indicate that GP-CTAB is still geopolymer even in the presence of quaternary ammonium salt cations. The material was tested to simultaneously adsorb Cu(II) and Cr(VI) from an aqueous solution. The results show that GP-CTAB can adsorb anions simultaneously without sacrificing the adsorption properties of heavy metal cations, which is superior to conventional geopolymers. The maximum theoretical adsorption capacity of GP-CTAB for Cu(II) and Cr(VI) was 108.2 mg/g and 95.3 mg/g in the binary system, respectively. It was also found that the presence of Cu(II) in the solution promoted the adsorption of Cr(VI). Given this characteristic of GP-CTAB, it has shown great application prospects in the prevention and control of heavy metal pollution.
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高影响因子
CHEMOSPHERE
·
2019
·
IF 5.108
Xin Huang,Yang Wan,Baoyou Shi,Jian Shi
The addition of powdered activated carbon (PAC) to remove micropollutants is a commonly used technology to improve drinking water quality . However, the effects of PAC dosing strategy on the coagulation-flocculation process of water treatment have not been well understood, especially for water with low amounts of inorganic particles. Therefore, the current research aimed to comprehensively study the effects of simultaneous addition of PAC and aluminum sulfate (AS) coagulants (denoted as PAC-AS) or adding PAC 2 h before coagulation (denoted as PAC2h-AS) on the coagulation behavior in humic acid (HA) and HA-kaolin water treatment. The results showed that the floc size, growth rate, breakage factor, and fractal dimension were all enhanced by PAC-AS and PAC2h-AS for HA but not for HA-kaolin water treatment. In HA water treatment, PAC-AS reached a larger floc size and faster growth rate, while PAC2h-AS achieved a larger floc breakage factor and fractal dimension value. For PAC2h-AS, the pre-adsorption of HA onto PAC would lower the initial particle concentration and reduce the collision probability during HA water coagulation process; thus, the DOC removal efficiency, floc size, and growth rate of PAC2h-AS were relatively smaller than those of PAC-AS. For the floc strength and floc fractal dimension, the pre-adsorption of HA onto PAC contributed to formation of stronger inter-particle bonds; thus, stronger and more compact flocs were formed by PAC2h-AS compared with those of PAC-AS. The addition of PAC had a smaller impact on the floc properties in HA-kaolin water treatment owing to its higher initial particle concentration.
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高影响因子
CHEMOSPHERE
·
2018
·
IF 4.427
Xinhao Ren,Fei Wang,Peng Zhang,Junkang Guo,Hongwen Sun
Biochars that were produced from pig manure at two different temperatures were incubated with three different minerals to examine the effects of soil minerals on biochar properties and sorption capacities. Biochars freshly mixed with minerals showed dramatic decreases in the sorption of atrazine (maximum decrease by 70.9% at C e = 0.5 S w ) and phenanthrene (maximum decrease by 69.5% at C e = 0.5 S w ) compared to unmixed biochars. Following the incubation, minerals were tightly attached to the biochar surface and insert into inner pores, thus changing the elemental composition and surface area of biochars in a manner dependent on the types of biochars and minerals involved. The changes in biochar properties in turn affected biochar sorption capacities. The sorption of both atrazine and phenanthrene by the pig manure biochar produced at 300 °C (BC300) decreased after aging due to an increase in surface hydrophilicity. In contrast, the sorption of atrazine and phenanthrene by BC700 increased after aging with minerals, which could be attributed to the increase in surface area caused by the minerals. However, the sorption capacities of the aged BC700 were still lower than those of the fresh BC700.
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ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Duanchao Wang,Houyong Yu,Xuemeng Fan,Jiping Gu,Shounuan Ye,Juming Yao,Qingqing Ni
Charged nanocellulose (NC) with a high aspect ratio (larger than 100) extracted from animal or bacterial cellulose and chemical cross-linked NC aerogels have great promising applicability in material science, but facile fabrication of such NC aerogels from plant cellulose by physical cross-linking still remains a major challenge. In this work, carboxylated cellulose nanofiber (CNF) with the highest aspect ratio of 144 was extracted from wasted ginger fibers by a simple one-step acid hydrolysis. Our approach could easily make the carboxylated CNF assemble into robust bulk aerogels with tunable densities and desirable shapes on a large scale (3D macropores to mesopores) by hydrogen bonds. Excitingly, these CNF aerogels had better compression mechanical properties (99.5 kPa at 80% strain) and high shape recovery. Moreover, the CNF aerogels had strong coagulation–flocculation ability (87.1%), removal efficiency of MB dye uptake (127.73 mg/g), and moderate Cu2+ absorption capacity (45.053 mg/g), which were due to assistance mechanisms of charge neutralization, network capture effect, and chain bridging of high aspect ratio carboxylated CNF. This provided a novel physical cross-linking method to design robust aerogels with modulated networked structures to be a general substrate material for industrial applications such as superabsorbent, flocculation, oil–water separation, and potential electrical energy storage materials.
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高影响因子
Nature Communications
·
2018
·Vol. 9
·期 1
·1-8
·
IF 12.353
Pan Xiao-Feng,Gao Huai-Ling,Lu Yang,Wu Chun-Yan,Wu Ya-Dong,Wang Xiang-Ying,Pan Zhi-Qiang,Dong Liang,Song Yong-Hong,Cong Huai-Ping,Yu Shu-Hong
Biomimetic assembly of high-quality nanosheets into nacre-like structures can produce macroscopic films with favorable mechanical and optical performances due to the intrinsic properties and high level of ordering of the nanoscale building blocks. Natural ground mica is abundant and exhibits great application potential. However, large size and low aspect ratio greatly limit its biomimetic assembly. Moreover, exfoliation of ground mica into high-quality nanosheets remains a significant challenge. Here, we report that large-scale exfoliation of ground mica into mono- or few-layered mica nanosheets with a production rate of ~1.0 g h − 1 can be successfully achieved. The mica nanosheets are then assembled into strong biomimetic polymeric mica film that inherits the high electric insulation, excellent visible transmittance, and unique ultraviolet-shielding properties of natural mica. Its overall performance is superior to that of natural sheet mica and other biomimetic films, making the polymeric mica film a suitable substrate for flexible and transparent devices.
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高影响因子
危险品化学品经营许可证（带存储）