scholarly journals Adsorption Removal of Humic Acid from Micro-Polluted Water Using in Situ Manganese Dioxide

2015 ◽  
Vol 1 (2) ◽  
Author(s):  
Zeng Yubin
Keyword(s):  
Humic Acid ◽  
Manganese Dioxide ◽  
Polluted Water ◽  
Adsorption Removal

Enhanced coagulation with in situ manganese dioxide on removal of humic acid in micro-polluted water

2015 ◽  
Vol 72 (3) ◽  
pp. 406-414
Author(s):  
Yubin Zeng ◽  
Ziyang Zeng ◽  
Junlin Wang
Keyword(s):  
Humic Acid ◽  
Manganese Dioxide ◽  
Ph Value ◽  
Orthogonal Experiment ◽  
Surface Characteristics ◽  
Polluted Water ◽  
Enhanced Coagulation ◽  
Total Solids ◽  
Solids Content

The morphology and surface characteristics of manganese dioxide (MnO2) formed in situ, which was prepared through the oxidation of MnSO4 using KMnO4, were studied. The effects of factors including the form of MnO2, dosage, pH, dosing sequence of in situ MnO2 on the enhanced coagulation were systematically evaluated. The results of analysis by the UV254 and permanganate index CODMn methods indicated that humic acid removal increased from 9.2 and 2.5% to 55.0 and 38.9%, when 10 mg/L of the in situ MnO2 was added in the presence of 2 mg/L of polyaluminum sulfate. The studies of orthogonal experiment revealed that coagulation was most affected by the pH, whereas the dosage of in situ MnO2 and slow stirring duration exhibited a weaker effect. At a pH value of 4.0, in situ MnO2 dosage of 10 mg/L, slow stir over 40 min, and the total solids content was 20 mg/L, the humic acid removal by UV254 and CODMn methods reached 71.2 and 61.2%. These results indicated that the presence of in situ MnO2 enhanced the coagulation and removal of humic acid from water.

scholarly journals Microwave Sensors for In Situ Monitoring of Trace Metals in Polluted Water

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3147
Author(s):  
Ilaria Frau ◽  
Stephen Wylie ◽  
Patrick Byrne ◽  
Patrizia Onnis ◽  
Jeff Cullen ◽  
...  
Keyword(s):  
Trace Metals ◽  
In Situ Monitoring ◽  
Polluted Water ◽  
Pollution Level ◽  
Mining Areas ◽  
Low Concentrations ◽  
The Uk ◽  
Microwave Sensors ◽  
Immediate Response

Thousands of pollutants are threatening our water supply, putting at risk human and environmental health. Between them, trace metals are of significant concern, due to their high toxicity at low concentrations. Abandoned mining areas are globally one of the major sources of toxic metals. Nowadays, no method can guarantee an immediate response for quantifying these pollutants. In this work, a novel technique based on microwave spectroscopy and planar sensors for in situ real-time monitoring of water quality is described. The sensors were developed to directly probe water samples, and in situ trial measurements were performed in freshwater in four polluted mining areas in the UK. Planar microwave sensors were able detect the water pollution level with an immediate response specifically depicted at three resonant peaks in the GHz range. To the authors’ best knowledge, this is the first time that planar microwave sensors were tested in situ, demonstrating the ability to use this method for classifying more and less polluted water using a multiple-peak approach.

scholarly journals Removal of Cd(II) from Micro-Polluted Water by Magnetic Core-Shell Fe3O4@Prussian Blue

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2497
Author(s):  
Xinxin Long ◽  
Huanyu Chen ◽  
Tijun Huang ◽  
Yajing Zhang ◽  
Yifeng Lu ◽  
...  
Keyword(s):  
Prussian Blue ◽  
Co Adsorption ◽  
Magnetic Core ◽  
Diameter Distribution ◽  
Polluted Water ◽  
Core Shell ◽  
Freundlich Model ◽  
Rate Limiting Step ◽  
Rate Limiting

A novel core-shell magnetic Prussian blue-coated Fe3O4 composites (Fe3O4@PB) were designed and synthesized by in-situ replication and controlled etching of iron oxide (Fe3O4) to eliminate Cd (II) from micro-polluted water. The core-shell structure was confirmed by TEM, and the composites were characterized by XRD and FTIR. The pore diameter distribution from BET measurement revealed the micropore-dominated structure of Fe3O4@PB. The effects of adsorbents dosage, pH, and co-existing ions were investigated. Batch results revealed that the Cd (II) adsorption was very fast initially and reached equilibrium after 4 h. A pH of 6 was favorable for Cd (II) adsorption on Fe3O4@PB. The adsorption rate reached 98.78% at an initial Cd (II) concentration of 100 μg/L. The adsorption kinetics indicated that the pseudo-first-order and Elovich models could best describe the Cd (II) adsorption onto Fe3O4@PB, indicating that the sorption of Cd (II) ions on the binding sites of Fe3O4@PB was the main rate-limiting step of adsorption. The adsorption isotherm well fitted the Freundlich model with a maximum capacity of 9.25 mg·g−1 of Cd (II). The adsorption of Cd (II) on the Fe3O4@PB was affected by co-existing ions, including Cu (II), Ni (II), and Zn (II), due to the competitive effect of the co-adsorption of Cd (II) with other co-existing ions.

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