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Residual aluminium in water intended for human consumption

Krupińska Izabela, Płuciennik-Koropczuk Ewelina, Gągała Sylwia

Civil and Environmental Engineering Reports

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2019

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Vol. 29, no. 4

248--256

EN

Aluminium is one of the environmental factors that may have an impact on Alzheimer's and Parkinson's disease. Some epidemiological studies show a relationship between the concentration of aluminium in drinking water and the incidence of Alzheimer's disease. The article presents and discusses the results of research on the effect of the type and dose of non-prehydrolyzed aluminium coagulants on the concentration of residual aluminium in water intended for human consumption. Aluminium sulphate (VI) and sodium aluminate were tested as coagulants. Analysis of the obtained test results showed that lower concentrations of residual aluminium were found after coagulation with aluminium sulphate (VI), which is hydrolyzed acidally, lowering the pH of the water in the range of 7.47 to 7.12 providing good conditions for the formation of Al(OH)3. A less useful coagulant due to the concentration of residual aluminium was sodium aluminate, which undergoes basic hydrolysis creating conditions for the transition of Al(OH)3 into soluble Al(OH).

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Problem glinu resztkowego w uzdatnianiu wody

Gumińska J., Gumińska M., Kubalczyk A.

Technologia Wody

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2015

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Nr 4 (42)

30--33

EN

Pre-hydrolysed coagulants are usually more effective in comparison to hydrolysing coagulants e.g. aluminium sulphate. They are particularly well suited at low temperatures and at low alkalinity of raw water. However, despite many advantages resulting from the use of this group of reagents there is a problem of residual alu-minium in the form of fine particles, which have a very negative effect on subsequent unit processes.

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Effect of Ti Addition on the Residual Aluminium Content and Mechanical Properties of the B4C-Al Composites Produced by Vacuum Infiltration

Xiaozhou C, Chao W., Xiangxin X., Gongjin C.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 4

2493--2498

EN

The effect of Ti addition on the residual Al content and mechanical properties of B4C-Al composites fabricated by vacuum infiltration was investigated in the present study. The B4C-Al composite materials were fabricated using [Ti+B4C] preforms preheated at 1700ºC for 1 h and Al alloys infiltrated in vacuum atmosphere at 1100ºC for 2 h. The phase composition indicated that TiB2 has high wettability to Al as a result of the preheating. SEM and EDX results revealed a number of Al dimples are on the fracture surface due to the existence of TiB2. When the content of added Ti increases to 30%, the [Ti+B4C] preform is characterized by a minimal porosity (33.11%) and a maximal density, a corresponding amount of residual Al of 33.11% and a minimal fracture toughness (5.03 MPa·m1/2) with a hardness of up to 63 HRC. The residual Al and the mechanical properties of the composite material preform were determined by the Ti content of the preform.

PL

Zbadano wpływ dodatku tytanu na resztkową zawartość Al i właściwości mechaniczne kompozytów B4C-Al wytworzonych przez infiltrację próżniową. Kompozyty B4C-Al lzostały wytworzone przez infiltrację stopów Al, w próżni, w 1100ºC przez 2 godziny, do wstępnie wygrzanych w 1700ºC przez 1 godzinę preform [Ti+B4C]. Faza TiB2 charakteryzuje się wysoką zwilżalnością przez Al na skutek wstępnego wygrzania. Wyniki analizy SEM i EDX ujawniły pewną liczbę wgłębień Al znajdujących się na powierzchni pęknięcia z uwagi na obecność TiB2. Gdy zawartość dodanego Ti wzrasta do 30%, preforma [Ti+B4C] charakteryzuje się minimalną porowatością (33,11%) i maksymalną gęstością, odpowiednią ilością resztkowego Al tj. 33.11%, minimalną odpornością na kruche pękanie (5,03 MPa·m1/2), i twardością do 63 HRC. Resztkowe Al i właściwości mechaniczne materiału kompozytowego preformy determinowane są przez zawartość Ti w preformie.