Mesoporous Ca–Mn–O as an efficient scavenger toward organic pollutants and heavy metals: ion exchange provoking ultrafast Fenton-like reaction based on the synergy of alkaline earth/transition metals

2018 ◽  
Vol 6 (20) ◽  
pp. 9528-9538 ◽  
Author(s):  
Yali Weng ◽  
Zhenzhang Weng ◽  
Zhiyu Liang ◽  
Haixia Lyu ◽  
Zanyong Zhuang ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Ion Exchange ◽  
Transition Metals ◽  
Organic Pollutants ◽  
Alkaline Earth ◽  
Complex Matrices ◽  
Short Time

An elegant synergy of Ca and Mn in CaMnx contributes to efficient purification of solutions containing complex matrices in a short time.

Topotactic route to synthesis of novel hydroxylated phases: I. Trioctahedral Micas

Clay Minerals ◽  
1986 ◽  
Vol 21 (2) ◽  
pp. 125-131 ◽  
Author(s):  
S. Komarneni ◽  
R. Roy
Keyword(s):  
Ion Exchange ◽  
Alkaline Earth ◽  
Water Molecules ◽  
Hydration Energy ◽  
Hydrothermal Conditions ◽  
Potential Applications ◽  
Clay Layers ◽  
First Time ◽  
Hydrolysis Of ◽  
Alkaline Earth Cations

AbstractK-depleted phlogopite mica was used as a topotactic precursor and treated with alkali (Li+, K+, , Rb+, Cs+), alkaline-earth (Mg2+, Ca2+, Sr2+, Ba2+) and trivalent (Al3+) cations under hydrothermal conditions of 200°C and 30 MPa pressure. K-, NH4-, Rb- and Cs-aluminosilicate micas were synthesised at 200°C in one day. The synthesis of Cs-aluminosilicate mica, with potential applications in the management of nuclear wastes, has been achieved for the first time by this approach. Ion exchange by Li+, Na+ and alkaline-earth cations under hydrothermal conditions did not produce anhydrous mica phases but resulted in hydrous phases with one or two layers of water molecules between the clay layers. The formation of hydrous phases may be attributed to the high hydration energy of the above cations compared to K+, , RB+ and Cs+. Ion exchange with Al3+ produced a chlorite-like phase because of the hydrolysis of Al3+ under these hydrothermal conditions. These studies are of relevance in the immobilization of wastes where hazardous ions can be fixed in highly stable insoluble phases like mica or chlorite.

scholarly journals Safety Assessment of the Presence of Heavy Metals and Organic Pollutants in Vended Street Foods from Selected Locations in Lagos State Nigeria

2020 ◽  
pp. 109-120
Author(s):  
G. I. Oyet ◽  
C. B. Samuel
Keyword(s):  
Heavy Metals ◽  
Particulate Matter ◽  
Organic Pollutants ◽  
Food Samples ◽  
Lead Content ◽  
Food Type ◽  
Street Food ◽  
Detectable Limit ◽  
Volatile Organic ◽  
Lagos State

This study was aimed at investigating the presence of heavy metals and volatile organic pollutants in street-vended foods sourced from three selected locations in Lagos State, Nigeria, to ascertain their safety level. The study was carried out using complete randomization design and Cluster sampling technique to source vended street foods from three locations (Marina, Yaba and Apapa). The eight Food products studied were roasted (plantain, fish, yam, corn), suya meat, meat pie, egg roll and doughnuts. Lead, Cadmium, Copper, Mercury, Iron, Zinc and organic pollutants in Foods and particulate matter in Environment were examined. Heavy metals detected in vended street foods from Marina, Yaba and Apapa Lagos were; iron, copper, lead and zinc, at level ranging from 0.14 mg/kg–2.80 mg/kg, 0.08 mg/kg – 0.27 mg/kg, 0.01 mg/kg – 0.18 mg/kg, and 0.01 mg/kg – 0.04 mg/kg, respectively. Mercury and Cadmium were below detectable limit. Significantly (P<0.05) higher iron presence of 2.80 mg/kg and 1.99mg/kg were respectively, noticed in suya from Apapa and roasted fish also from Apapa. Significantly (P<0.05) higher lead (Pb) content of 0.18 mg/kg was observed in dough nut from Yaba, however, roasted plantain, roasted fish and meat pie all sourced from Yaba gave significantly (P<0.05) lower lead content of 0.01mg/kg. The Zinc content of roasted fish, suya and egg roll sourced from Marina, Yaba and Apapa were all significantly (P<0.05) difference, with particular respect to food type. Higher iron content of 2.80 mg/kg was noticed in suya from Apapa. Volatile organic compounds (TPH, PAHs, Phenol) were observed to be below detectable limit (<0.001 mg/kg) in all the vended street food samples. Particulate matter in air; SPM, PM1, PM2.5, PM10 and VOCs ranged from 0.34 – 0.84 mg/m3, 0.32 – 0.56 mg/m3, 0.32 – 0.68 mg/m3, 0.33 – 0.79 mg/m3 and <0.001 – 0.24 mg/m3, respectively. PM1 and PM25 from the three locations were not statistically significant (P>0.05). All the vended food samples had lead (Pb) content above the CODEX permissible limit of 0.01 mg/kg. The presence of high lead content in Vended Street food is a major source of occupational health hazards.

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