Wyniki wyszukiwania - BazTech

1

Waste Water Purification from Metal Ions by Ultra-Dispersed Natural Sorbents

Yerbolov Sezim, Daumova Gulzhan

Journal of Ecological Engineering

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2022

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Vol. 23, nr 1

43--50

EN

This work is devoted to mine wastewater purification from metal ions, such as copper, zinc, lead, cadmium, iron, and manganese. The rationale was provided for the possibility to purify the wastewater from metal ions with nonactivated and ultra-dispersed natural sorbents. The adsorption capacity of bentonite clay from Tagan deposit and shungite from Koksui deposit of the Republic of Kazakhstan was studied on the basis of its fraction composition. It was found that the most effective method of sorbents modification was mechanical activation. The comparative studies of metal ions adsorption efficiency were carried out with mechanically activated and ultra-dispersed bentonite clay and shungite. The experiment enabled to find out that ultra-dispersed bentonite clay is prospective for use in order to deeply purify multicomponent mine wastewater. The highest degree of metal ions extraction was achieved due to 30-minutes contact of wastewater.

2

Impact of ovalbumin on pyrite flotation in the absence and presence of metal ions

Guler T., Sahbudak K., Akdemir U., Cetinkaya S.

Physicochemical Problems of Mineral Processing

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2014

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Vol. 50, iss. 1

31--40

EN

Recovery of gangue pyrite and its accidental activation are vital issues in flotation of complex sulfide ores. This work was performed by cyclic voltammetry (CV) and flotation tests to elucidate applicability of ovalbumin (OVA) as depressant for pyrite. The synergetic effect of metal ions in addition to its possible use in case of accidental activation by metal ions. CV tests stated that OVA adsorbed irreversibly on pyrite, and restricted electron transfer up to moderately oxidizing potentials due to electrostatic interaction together with weak hydrophobic interactions. At highly oxidizing potentials, adsorption occurred through electrochemical mechanisms through formation of metal-OVA chelates. Rate of pyrite depression with OVA was found to be potential dependent reaching its peak point around moderately oxidizing potentials both in absence and presence of metal ions. Electrochemically active metals display synergetic effect with OVA on pyrite depression, whereas noble metals activate pyrite and reduced depressing potency of OVA.

3

Zastosowanie polimerowych membran inkluzyjnych w procesach transportu jonów metali

Baczyńska M., Regel-Rosocka M., Wiśniewski M.

Przemysł Chemiczny

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2013

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T. 92, nr 6

928--935

4

Karbonatyzacja a trwałość procesu immobilizacji wybranych metali ciężkich (Zn2+,Cr6+, Pb2+) w kompozytach cementowych

Król A., Jagoda D.

Cement Wapno Beton

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2012

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R. 17/79, nr 2

90-101

PL

Zbadano stopień wpływu karbonatyzacji zapraw lub betonów na ich zdolność do immobilizacji wybranych metali ciężkich: Cr, Zn i Pb. Uzyskane wyniki pokazują, że kompozyty cementowe stanowią skuteczną metodę składowania odpadów i karbonatyzacja, w badanym zakresie, nie ma niekorzystnego wpływu na potencjał immobilizacyjny tych matryc. Jednak ważnym problemem jest wybór odpowiedniego cementu dla bezpiecznego związania niebezpiecznego odpadu. Należy zbadać wpływ tego odpadu na hydratację cementu w celu uniknięcia zakłóceń tego procesu i w efekcie zmniejszenia wytrzymałości zapraw lub betonów. W przypadku negatywnego wpływu odpadu trzeba wybrać odpowiedni cement, lub zmniejszyć zawartość metali ciężkich przez zmieszanie odpadu z obojętnym dodatkiem, na przykład drobnym piaskiem.

EN

The degree of carbonation of the mortar and concrete on their immobilization behaviour of heavy metals: Cr, Zn and Pb was studied. The results have shown that cement composite is an effective method of waste disposal and carbonization, in a studied range, has no disadvantageous effect on the immobilisation potential of this matrix. However, in the selection of cement type for the solidification of the particular hazardous waste The influence of the waste on the cement hydration should be verified in order to avoid the disturbance of this process and consequently of mortars or concretes strength decrease. In the case of an negative effect the suitable cement must be chosen, or the dilution of heavy metal content by mixing the waste with suitable inert material, for example fine sand.

5

Kinetics and Mechanism of Metal cation Catalysis in the Hydrolysis of p-Nitrophenyl Picolinate (PNPP)

Cheng S.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 5

933-939

EN

The hydrolysis of PNPP was investigated in the presence and absence of Co(II), Cu(II), Ni(II), Zn(II), La(III) at 25°C and ionic strength of 0.1 mol dm-3. The results indicate that the spontaneous hydrolysis of PNPP was catalyzed by hydronium ion, hydroxide ion and water molecule, because of the existence of the pyridium nitrogen, while the metal ion catalyzed hydrolysis of PNPP at zero buffer concentration fulfills the equation: k obsd=K a [H+]+K a (k H[H+]+k 0+k OH K W [H+] showing that the reaction proceeds via nucleophilic attack by external OH- on the metal ion complex of PNPP. The order of catalytic ability of different metal ions was interpreted by the stability of the complex structure relative to the structure of the groundstate intermediate, employing the method devised by Kurz for catalyzed reaction.