Enhanced nitrate-nitrogen removal by modified attapulgite-supported nanoscale zero-valent iron treating simulated groundwater

Dong, Lei; Li, Lin; Li, Qingyun; Huang, Zhe; Tang, Xianqiang; Wu, Min; Li, Chao; Xiao-huan, Cao; Scholz, Miklas

doi:10.1016/j.jenvman.2018.02.073

Cited by 56 publications

(27 citation statements)

References 35 publications

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“…Approximately 20 mg of each powered sample was analyzed for TOC and TN using a C analyzer (TOC-VCSH, Shimadzu Corp., Kyoto, Japan). Concentrations of NH 4 –N were analyzed using a UV-vis spectrophotometer at a wavelength of 420 nm (22). Concentrations of NO 3 –N were determined using a UV-vis spectrophotometer applying double wavelength of 275 nm and 220 nm (22).…”

Section: Methodsmentioning

confidence: 99%

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Regulating Soil Bacterial Diversity, Enzyme Activities and Community Composition Using Residues from Golden Apple Snails

Wang

Zhang

et al. 2019

Preprint

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11Golden apple snails (GAS) have become a serious pest for agricultural 12 production in Asia. A sustainable method for managing GAS is urgently needed, 13 including potentially using them to produce commercial products. In this study, we 14 evaluate the effects of GAS residues (shell and meat) on soil pH, bacterial diversity, 15 enzyme activities, and other soil characteristics. Results showed that the amendment 16 of GAS residues significantly elevated soil pH (to near-neutral), total organic carbon 17 (TOC) (by 10-134%), NO 3 -N (by 46-912%), NH 4 -N (by 18-168%) and total nitrogen 18 (TN) (by 12-132%). Bacterial diversity increased 13% at low levels of amendment 19 and decreased 5% at high levels, because low-levels of GAS residues increased soil 20 pH to near-neutral, while high-levels of amendment substantially increased soil 21 nutrients and subsequently suppressed bacterial diversity. The dominant phyla of 22 bacteria were: Proteobacteria (about 22%), Firmicutes (15-35%), Chloroflexi 23 (12%-22%), Actinobacteria (8%-20%) Acidobacteria, Gemmatimonadetes, 24 Cyanobacteria and Bacterioidetes. The amendment of GAS residues significantly 25 increased the relative abundance of Firmicutes, Gemmatimonadetes, Bacterioidetes 26 and Deinococcus-Thermus, but significantly decreased the relative abundance of 27Chloroflexi, Actinobacteria, Acidobacteria, Cyanobacteria and Planctomycetes. Our 28 results suggest that GAS residues treatment induces a near-neutral and nutrient-rich 29 soil. In this soil, soil pH may not be the best predictor of bacterial community 30 composition or diversity; rather soil nutrients (ie., NH 4 -N and NO 3 -N) and soil TOC 31 showed stronger correlations with bacterial community composition. Overall, GAS 32 3 residues could replace lime for remediation of acidic and degraded soils, not only to 33 remediate physical soil properties, but also microbial communities. 34

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Section: Methodsmentioning

confidence: 99%

“…Concentrations of NH 4 –N were analyzed using a UV-vis spectrophotometer at a wavelength of 420 nm (22). Concentrations of NO 3 –N were determined using a UV-vis spectrophotometer applying double wavelength of 275 nm and 220 nm (22). Concentrations of AP were analyzed using the molybdenum-antimony anti-spectrophotometric method (23).…”

Section: Methodsmentioning

confidence: 99%

Regulating Soil Bacterial Diversity, Enzyme Activities and Community Composition Using Residues from Golden Apple Snails

Wang

Zhang

et al. 2019

Preprint

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“…Coagulation-occulation, a proven technology in surface water remediation and sewage treatment, now has been widely used in plenty of water treatment occasions [25][26][27]. Addition of coagulants could promote agglomeration of suspended particles (including microorganisms), further deposit the latter to the bottom by gravity.…”

Section: Introductionmentioning

confidence: 99%

Coagulation-Flocculation: A potential Application for Mosquito Larval Source Management (LSM) with No Insecticide Resistance

Li¹,

Huang²,

PeiEn³

et al. 2020

Preprint

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Background: Mosquito control is an essential step to eliminate mosquito-borne diseases. Larval mosquitoes have a more limited home range and lower resistance to adverse environment than adults, thus can be ideal targets for vector control in some cases. Coagulation-flocculation technology, which could be used for water treatment in breeding sites of several vector mosquito species, can significantly change both the distribution of organic particles and surface sediment characteristics in water environment. The aim of this study was to explore the effect, principle and possibility of using coagulation-flocculation technology in immature mosquitoes killing.Method: In laboratory, chlorine-free tap water was treated with Poly Aluminum Chloride (PACl, sewage treatment using). The oviposition preference of gravid Culex pipiens pallens, the hatching of mosquito eggs and the survival amount of mosquito larvae were observed, and the pupa amounts were recorded each day.Results: Coagulation-flocculation treatment could improve the oviposition preference of Culex pipiens pallens to some extent (compared with ordinary chlorine-free tap water), but not significantly (p=0.345). After treatment, mosquitoes laid eggs in chlorine-free tap water were 31.88% more than those laid in untreated water. Coagulation-flocculation affected the larvae’s survival by physical means: Ⅰ) alum floc layer increases the difficulty of larvae foraging, leads larvae starving to death; (Ⅱ) the little floc particles adhere to the surface of larvae, which stops larvae from floating upward to breathe. As a result, the alum floc layer had a good killing effect on the mosquito larvae, presented the half lethal time (LT50) of 2d, the 90% lethal time (LT90) of 8.7±7.3 ~ 14±4.5 d, and the pupation rate of 0 ~ (6.5±0.5)%, respectively.Conclusions: PACl coagulation-flocculation produced lots of alum flocs, which may attract more gravid mosquitoes for laying eggs, and was shown to be highly active against 1st~2nd instar larvae. The principle of this technology illustrates this method won’t develop insecticide resistance. In this study, coagulation-flocculation technology is considered to be a new potential approach to a sustainable, low-impact and low-cost mosquito control method.

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“…However, raw clay minerals were rarely utilized unless modified by physicochemical methods. Modified clay minerals such as thermally activated titanium‐rich bauxite, chemically modified bentonite clay, natural stilbite zeolite modified with Fe(III) and modified attapulgite have been studied for fluoride removal. However, most of these adsorbents could only adsorb fluoride efficiently in a very narrow pH range.…”

Section: Introductionmentioning

confidence: 99%

Volcanic rock‐based ceramsite adsorbent for highly selective fluoride removal: function optimization and mechanism

Chao

Zhao

Song

et al. 2019

J of Chemical Tech & Biotech

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BACKGROUND: While various granular adsorbents have been studied for fluoride removal from water, this study focuses on the optimization of mixture proportions of volcanic rock, bentonite, corn starch and aluminum sulfate using a four-component simplex-centroid mixture design (SCMD) method to achieve preferable fluoride removal ratio and ceramsite mechanical strength. To illustrate the adsorption mechanism, a series of experiments, including adsorption isotherms, adsorption kinetics and effects of pH value and co-existing anions, was carried out. RESULTS: The synthesized adsorbent was mesoporous with 77.82% pore size distribution in the range 1.70-38.80 nm by detailed physicochemical characterization. A stable fluoride removal ratio (87.5%) was obtained in the wide pH range of 4.0-11.0, and the adsorption capacity was 10.17 mg g −1 at 298 K. The adsorbent remained high selectivity for F − in the presence of sulfate (SO 4 2− ), chloride (Cl − ) and nitrate (NO 3 − ), while carbonate (HCO 3 − ) posed a slight adverse effect on F − adsorption due to ion competition. This adsorption process was well fitted with the pseudo-second-order kinetic model and the Freundlich isotherm model. Electrostatic attraction and M + -H 2 O and M + -F ligand exchange were dominant in the adsorption mechanisms. CONCLUSION: The synthesized ceramsite adsorbent will be competitive in the application for F − removal from aquatic environments.

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Enhanced nitrate-nitrogen removal by modified attapulgite-supported nanoscale zero-valent iron treating simulated groundwater

Cited by 56 publications

References 35 publications

Regulating Soil Bacterial Diversity, Enzyme Activities and Community Composition Using Residues from Golden Apple Snails

Regulating Soil Bacterial Diversity, Enzyme Activities and Community Composition Using Residues from Golden Apple Snails

Coagulation-Flocculation: A potential Application for Mosquito Larval Source Management (LSM) with No Insecticide Resistance

Volcanic rock‐based ceramsite adsorbent for highly selective fluoride removal: function optimization and mechanism

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