SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
·
IF 10.753
Xingwen Lu,Wang Xu,Qinghuai Zeng,Weizhen Liu,Fei Wang
Struvite precipitation is a promising strategy for the simultaneous recovery of nitrogen and phosphorus from waste streams. However, waste streams typically contain high amounts of metal contaminants, including Ni, which can be easily sequestered by struvite, but the behavior of Ni during struvite precipitation remains unclear. Thus, this study investigates the influence of Ni concentrations on struvite precipitation. The quantitative X-ray diffraction (QXRD) results revealed that the purity of struvite decreased from 96.6 to 41.1% with the Ni concentrations increased from 0.1–100 mg·L −1 . At lower Ni concentrations of 0.1–1 mg·L −1 , scanning electron microscopy (SEM) showed a roughened surface of struvite crystal, and this was combined with X-ray absorption near edge structure (XANES) data that indicated a stack of Ni-OH and Ni-PO 4 on struvite surface. At Ni concentrations of 10–25 mg·L −1 , Ni primarily crystalized as Ni-struvite (NiNH 4 PO 4 ·6H 2 O), as detected by QXRD. At higher Ni concentrations of 25–100 mg·L −1 , the co-precipitation of amorphous Ni phosphate(s) (e.g., Ni 3 (PO 4 ) 2 ) and Ni hydroxide (e.g., Ni(OH) 2 ) was identified by XANES. Specifically, the X-ray photoelectron spectroscopy (XPS) analysis detected the formation of amorphous Mg hydroxide(s) and phosphate(s) at Ni of 25–100 mg·L −1 . The overall results revealed that Ni formed Ni-OH and Ni-PO 4 on struvite surface at 0.1–1 mg·L −1 , whereas Ni precipitated as separated phases (e.g. Ni-struvite, Ni hydroxide and phosphate) at 10–100 mg·L −1 . The existence of Ni disturbed the crystal growth of struvite and promoted the formation of Ni-struvite, amorphous products during struvite formation.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Crystals
·
2017
·Vol. 7
·期 9
·275
·
IF 1.566
Yang Shu,Wenchao Yan,Haisong Wang,Jicheng Jiang,Deye Sun,Xiaodi Ma,Yongcheng Jin
A series of LiNi0.5Mn1.5O4(LNMO) samples were synthesized by adjusting the molar ratio of (NH4)2CO3to Na2CO3in a mixed precipitant for evaluating the effects of ammonia from (NH4)2CO3as a complexing agent and Na2CO3as a precipitant on the morphology and electrochemical performances of LNMO. In this research, a rapid precipitation method followed by hydrothermal treatment was used to prepare the precursors of LNMO, and different molar ratios (0:1, 1:2, 1:1, 2:1, 1:0) of (NH4)2CO3to Na2CO3were used for mixed precipitants. The test results revealed that the cathode material exhibits the best electrochemical performance when the molar ratio of (NH4)2CO3to Na2CO3is set at 1:2, displaying a specific discharge capacity of 129.4 mA h g−1at 0.5 C and a capacity retention of 82.3% after 200 charge–discharge cycles. In addition, it still shows a high rate performance with a discharge capacity of 112.7 mA h g−1at 10 C and 98.8 mA h g−1at 20 C, which is attributed to an accurate Ni/Mn ratio, smaller primary particle sizes and a porous spherical morphology.Keywords:rapid precipitation;hydrothermal treatment;mixed precipitants;spherical morphology
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2017
·
IF 4.208
Jun Wan,Xiaoqing Jiang,Tian C. Zhang,Jiong Hu,Dana Richter-Egger,Xiaonan Feng,Aijiao Zhou,Tao Tao
Finding a good sorbent for phosphorus (P) recovery from the aquatic environment is critical for preventing eutrophication and providing P resources. The activated iron system (mainly consisted of zero-valent iron (ZVI), Fe 3 O 4 and Fe 2+ ) has been reported to exhibit a favorable performance towards various contaminants in wastewater, but its effect on P recovery has not been studied systematically. In this study, we used Fe 2+ -nitrate pretreatment reaction to prepare the activated iron system and then applied it to P recovery. Results show that more than 99% P was removed from water in 60 min; co-existing anions (NO 3 − , Cl − and SO 4 2− ) and natural organic matter (NOM) had little effect on P removal. The P removal capacity of activated iron system is very high compared with currently reported sorbents. Externally-supplied Fe 2+ plays an important role on P removal in the system. Regeneration study shows that the activated iron system exhibited stable P recovery ability by using 0.1 M NaOH solution. Various methods were applied to characterize the ZVI and iron corrosion, and results conclude that sorption precipitation, and co-precipitation contribute to P removal. This method will be promising and have an application potential in the field for efficient and cost-effective recovery of P with cheap microscale zero valent iron.
研究领域:
环境科学
·
水资源管理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MINERALS ENGINEERING
·
2022
·
IF 5.479
Xianping Luo,Xianqiang Yuan,Kunzhong He,Yongbing Zhang,Caigui Luo,Zishuai Liu,Hepeng Zhou
Impurity metal ions in ionic rare earth ores are similar to rare earth ions in terms of occurrences and similarities in properties. During the leaching operation, a large number of impurity ions enter the rare earth leaching solution, which makes the crystal form of the rare earth unstable or forms an amorphous flocculent precipitate. The commonly used ammonium bicarbonate (NH 4 HCO 3 ) precipitation crystallization process has low rare earth precipitation rate, long precipitation crystallization period, and high ammonia nitrogen content in precipitation wastewater. In this paper, the leaching solution obtained by ionic rare earth ore magnesium salt leaching-combined impurity removal process was taken as the research object, and the effects of precipitants, such as NH 4 HCO 3 , calcium oxide, sodium carbonate, and oxalic acid, on the preparation of crystalline rare earth precipitation were investigated through comparison. On the premise of determining the best rare earth precipitant, the effects of dosage, stirring speed, stirring time, and aging time on the preparation of crystalline rare earth precipitate were investigated further. The precipitation effects of different precipitation processes were studied systematically combined with SEM-EDS, laser particle size analysis, and other means to characterize the morphology of crystalline products. Results showed that when calcium oxide was used as a precipitant, the molar ratio was 2.5. After stirring at a constant speed of 200 r/min for 4 h and aging for 4 h, precipitates with good crystal appearance, smooth crystal surface and easy filtration were obtained. This process promoted crystal growth of rare earth precipitates, and the crystal grain size, which was beneficial to the improvement of the quality of rare earth products, increases significantly.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
·
2025
·
IF 12.4
Xian Zhao,Jia-Yi Wang,Yu-Qian Wang,Chen-Hao Cui,Xin Yan,Wei Dai,An-Ran Zhang,Zhen-Ying Zhang,Ding-Ding Tang,Yan Zhou,Qiong Qin,Ji-Wei Pang,Lu-Yan Zhang,Nan-Qi Ren,Jie Ding,Shan-Shan Yang
s Green rust (GR), a reductive iron-based mineral pivotal in soil and groundwater remediation, remains unexplored for wastewater treatment. This study reveals that high-pH-Fe(II) coagulation enables in-situ generation of stabilized GR, thereby enhancing the coagulation efficiency (> 90 % removal for diverse dyes). The formation mechanism includes three sequential stages: Initially, alkaline conditions facilitate abundant Fe(OH) 2 ; Subsequently, partial oxidation of Fe(II) by oxidants produces anoxic zones, where Fe(II)/Fe(III) co-precipitation initiates GR crystallization; Simultaneously, multivalent anions intercalate into GR interlayers, further enhancing GR stability through strong electrostatic interactions. GR-enhanced-Fe(II) coagulation demonstrates dual dyes removal mechanisms: direct reductive degradation of electrophilic moieties (e.g., azo bond) and adsorption-coprecipitation of macromolecules. Based on the mechanism insights, it is found that GR-enhanced-Fe(II) coagulation achieves unparalleled removal of both anionic and cationic dyes (nearly 100 % decolorization for 50 mg/L dye solutions) under anoxic conditions. HPLC-MS and DFT confirm GR-driven reductive cleavage of Reactive Red 2 into low-molecular-weight byproducts. Pilot and full-scale trials at a dyeing wastewater treatment plant concluded that GR-enhanced-Fe(II) coagulation achieves 53.5 % COD removal, outperforming conventional Fe(II) processes (46.5 %) under actual hydraulic and pollutant load fluctuations. This work expands coagulation theory and offers a cost-effective strategy for wastewater treatment, adaptable to diverse effluents while retaining operational simplicity.
研究领域:
环境科学
·
水处理技术
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2019
·
IF 4.63
Liu Zhong,Qingyan Fang,Xin Li,Quan Li,Cheng Zhang,Gang Chen
Various catalysts were synthesized by the redox-precipitation (RP) and co-precipitation (CP) methods, and their catalytic performances for the complete catalytic oxidation of lean methane combustion were investigated. The synthetic catalysts were characterized by BET, XRD, Raman, XPS, TG, UV–vis and H2-TPR. MnCe-RP showed 50% methane conversion to CO 2 at ˜446 °C, which was 23 °C lower the temperature required for MnCe-CP. The active components (K x Mn 8 O 16 ) in the bulk and on the surface of MnCe-RP were confirmed. The redox-precipitation method synthesized open nanorod and nanosphere catalysts containing K x Mn 8 O 16 and Mn 5 O 8 , whereas the co-precipitation method synthesized agglomerate catalysts containing only Mn 5 O 8 . The higher surface-concentrations of Mn 4+ , Ce 3+ and O α on MnCe-RP are beneficial for its higher catalytic performance. Furthermore, the optical bandgap value of MnCe-RP is lower than that of MnCe-CP, and the K ion in K x Mn 8 O 16 may weaken the Mn-O bond, improving the catalyst reducibility, especially for the reduction process of Mn 3 O 4 →MnO.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2023
·
IF 13.6
Yingpeng Gu,Yue Sun,Weisheng Zheng
Cupric (Cu(II)) complexes in industrial wastewater are responsible for the failure of conventional alkaline precipitation, but the properties of cuprous (Cu(I)) complexes at alkaline circumstance have not been focused. This report proposed a novel strategy for the remediation of Cu(II)-complexed wastewater by coupling alkaline precipitation with green benign reductant, namely, hydroxylamine hydrochloride (HA). This remediation process (HA-OH) exhibits superior Cu removal efficiency that cannot be achieved with the same dosage of oxidants (3 mM). The possibility of Cu(I) activated O 2 catalysis and self-decomplexation precipitation were investigated, and the results identified that 1 O 2 was generated from Cu(II)/Cu(I) cycle, but it was insufficient to annihilate organic ligands. Cu(I) self-decomplexation was the dominate mechanism of Cu removal. For real industrial wastewater, HA-OH process can realize the efficient Cu 2 O precipitation and Cu recovery. This novel strategy utilized intrinsic pollutant in wastewater without introducing other metals, complicated materials, and expensive equipment, broadening the insight for the remediation of Cu(II)-complexed wastewater.
研究领域:
环境工程
·
废水处理
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
IONICS
·
2021
·Vol. 27
·期 11
·4829-4838
·
IF 2.817
Han Wei,Zhang Yingchun,Liu Rugeng,Sun Yang,Li Mei
In order to recover salt and minimize waste volume, a sequential precipitation method was proposed to remove rare earth (RE = La, Sm, Nd, Dy), Cs, Sr, and Ba from spent electrolyte in the form of phosphate and carbonate precipitation, respectively. The thermodynamic calculation confirmed the feasibility of the process. The precipitation results indicated that RE 3+ and Cs + could be converted to insoluble phosphates using Na 3 PO 4 , whereas Sr 2+ and Ba 2+ to insoluble carbonates by adding K 2 CO 3 . Meanwhile, the phosphate precipitation process was monitored online by square wave voltammetry, and the results showed that with the addition of Na 3 PO 4 , the peak current densities corresponding to the reduction of RE 3+ decreased gradually. The molten salt containing La 3+ , Sm 3+ , Nd 3+ , Dy 3+ , Cs + , Sr 2+ , and Ba 2+ was used to simulate the waste electrolyte for sequential precipitation; the removal rates of RE, Sr, and Ba were found to be over 95.00%, except for Cs 79.17%. Graphical abstract In order to recover the molten salt, the sequential precipitation method was proposed to remove rare earth (RE = La, Sm, Nd, Dy), Cs, Sr, and Ba from spent electrolyte. RE and Cs were separated using Na 3 PO 4 and Sr and Ba using K 2 CO 3 . The removal rates estimated by ICP-OES were found to be over 95.00%, except for Cs.
研究领域:
环境工程
·
化学工程
·
分析化学
·
废物管理
✓ 已验证
产品关联
DOI
高影响因子
Frontiers in Bioengineering and Biotechnology
·
2023
·
IF 5.7
Wang Lin,Cheng Wen-Chieh,Xue Zhong-Fei,Rahman Md Mizanur,Xie Yi-Xin,Hu Wenle
Inappropriate irrigation could trigger migration of heavy metals into surrounding environments, causing their accumulation and a serious threat to human central nervous system. Traditional site remediation technologies are criticized because they are time-consuming and featured with high risk of secondary pollution. In the past few years, the microbial-induced carbonate precipitation (MICP) is considered as an alternative to traditional technologies due to its easy maneuverability. The enzyme-induced carbonate precipitate (EICP) has attracted attention because bacterial cultivation is not required prior to catalyzing urea hydrolysis. This study compared the performance of lead (Pb) and copper (Cu) remediation using MICP and EICP respectively. The effect of the degree of urea hydrolysis, mass and species of carbonate precipitation, and chemical and thermodynamic properties of carbonates on the remediation efficiency was investigated. Results indicated that ammonium ion (NH4+) concentration reduced with the increase in lead ion (Pb2+) or copper ion (Cu2+) concentration, and for a given Pb2+ or Cu2+ concentration, it was much higher under MICP than EICP. Further, the remediation efficiency against Cu2+ is approximately zero, which is way below that against Pb2+ (approximately 100%). The Cu2+ toxicity denatured and even inactivated the urease, reducing the degree of urea hydrolysis and the remediation efficiency. Moreover, the reduction in the remediation efficiency against Pb2+ and Cu2+ appeared to be due to the precipitations of cotunnite and atacamite respectively. Their chemical and thermodynamic properties were not as good as calcite, cerussite, phosgenite, and malachite. The findings shed light on the underlying mechanism affecting the remediation efficiency against Pb2+ and Cu2+.
研究领域:
环境科学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
·
2021
·
IF 9.297
Liu Xia,Wenjuan Zhang,Jianyong Che,Jun Chen,Peicheng Wen,Baozhong Ma,Chengyan Wang
Phosphate and fluoride are the two most crucial contaminants in water resources. In this work, fluoride and phosphate were separately removed and recovered from wastewater through the step-by-step precipitation method. The thermodynamic analysis proved that the process could be achieved by controlling the pH value and the optimal operating window was predicted by constructing the lg c -pH diagram of the La–F–P–H 2 O system. Lab-scale experiments were performed using La 3+ as a precipitant and the results were well matched with thermodynamic analysis. It indicated that the precipitation of LaF 3(s) was predominated at 1.0< pH < 4.0 with slight precipitation of phosphate, while LaPO 4(s) was primarily formed at a pH range of 5.0–11.0 with fluoride left in the solution. Furtherly, the generated LaF 3 and LaPO 4 were treated with NaOH solution to regenerate the precipitant and recycle fluorine and phosphorus, and the regeneration efficiency reached 97.4% and 74.3%, respectively. Eventually, the continuous experiment for the simulated wastewater revealed that 97.7% of fluoride and 99.9% of phosphate could be removed and recovered by the proposed stepwise precipitation method. The process is eco-friendly and sustainable, not only realizing the removal and recovery of F and P efficiently but also making them separated.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2024
·
IF 8.1
Yanfang Huang,Meimei Wang,Bingbing Liu,Shengpeng Su,Hu Sun,Shuzhen Yang,Guihong Han
Ion precipitation flotation technology was demonstrated to be an efficient method for the separation of valuable metals from low-concentration solution. However, the selective separation of three metals from mixing solution is a great challenge, and highly selective reagents are the key to polymetallic separation. In this work, stepwise separation of Co and Zn from the simulated zinc hydrometallurgy wastewater containing ternary Co–Zn–Mn metals by ion precipitation flotation process was proposed. It's demonstrated that organic reagents of 1-nitroso-2-naphthol (NN) and sodium dimethyldithiocarbamate (SDDC) had excellent selectivity for the capture of Co and Zn to form respective precipitate from wastewaters via the chelation reactions. After precipitation, dodecylpyridinium chloride (DPC) and tetradecyltrimethylammonium bromide (TTAB) were chosen as surfactants for the separation of Co and Zn sediments from the solution via the flotation process. The effects of solution pH, molar ratio, reaction temperature, and reaction time on the selective precipitation efficiencies of Co and Zn as well as the effects of surfactant dosage and flotation gas velocity on the flotation separation efficiencies were systematically investigated. It's demonstrated that the comprehensive recovery rates of Co, Mn, and Zn reach 98%, 90%, and 99%, respectively. After separation, oxidation calcination of the foam products was conducted to prepare high-purity Co 3 O 4 and ZnO nanoparticles in which the organic matters were burnt out with gas emissions. The stepwise chelation capture mechanisms of Co and Zn by highly selective precipitation reagents were minutely discussed. It's demonstrated that the proposed selective stepwise precipitation and flotation method is suitable for recovery of critical metal ions from low-concentration polymetallic wastewaters.
研究领域:
环境科学
·
冶金工程
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Acta Geotechnica
·
2023
·Vol. 18
·期 10
·5299-5318
·
IF 5.7
Zhao Chang,Xiao Yang,Chu Jian,Hu Ran,Liu Hanlong,He Xiang,Liu Yi,Jiang Xiang
Enzymatically induced carbonate precipitation (EICP) in heterogeneous subsurface is of interest in various geoscience and environmental applications. Through fabricating microfluidic cells with different pore networks, the pore-scale formation of biological CaCO 3 was investigated experimentally by transverse mixing using time lapse high-resolution camera. The precipitation pattern over time was processed to obtain the evolution of distribution of CaCO 3 volume fraction. The impact of flow rate and pore-scale heterogeneity were quantitatively evaluated with reaction index including overall pore filling ratio, precipitation rate and precipitation efficiency. The results showed that low flow rates and strong heterogeneity in porous media are the two favorable conditions for precipitation process due to more nucleation sites. At grain scale, a statistic of three-dimensional morphologies of individual crystals was evaluated with specific surface area and degree of anisotropy. Localized precipitates in multiple pores were adopted as a representative of the whole porous media. The analysis showed that the complex pore structures are generated due to precipitates in pores, thus limiting transport of reactants and result in the permeability reduction. We furthermore confirmed different polymorphs of calcium carbonate, mainly containing vaterite and calcite. Pore-scale analysis of biological CaCO 3 in porous media significantly contributes to the understanding of advection–diffusion-reaction coupling effect, and further revealing the role of pore network on biomineralization process.
研究领域:
地质科学
·
环境科学
·
生物矿化
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）