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1

The use of Zeta Potential Measurement as a Control Tool of Surface Water Coagulation

Mroczko Dominik, Zimoch Izabela

Journal of Ecological Engineering

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2020

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Vol. 21, nr 3

237--242

EN

The implementation or optimization of the coagulation process requires prior preliminary tests. Standard Jar-Test method is time-consuming, inaccurate and may not work well, especially for the waters characterized by high variability of quality parameters. Zeta Potential Isoelectric Point (IEP) analysis may give fast and precise data on the coagulant type and dose required for maintaining an efficient coagulation process. The research objects included the surface waters taken directly from the Mała Panew and Odra rivers. The zeta potential and set coagulant dose dependence was measured for each sample. Four aluminum-based coagulants with different characteristics were used in this research: aluminum sulfate (Alum), polyaluminum chloride (PAC), dialuminum chloride pantahydroxide (PACl), polyaluminum chloride hydroxide sulfate (PACS). Charge neutralization effectiveness, by means of Zeta Potential IEP analysis, was the basis for the choice of the most effective coagulant doses. The coagulation process efficacy was based on the parameters of the treated water (pH, turbidity, color, alkalinity), reduction of organic matter (Abs254, Total Organic Carbon (TOC), Dissolved Organic Carbon (DOC)) and residual aluminum contamination. The Zeta Potential utility evaluation was based on the DOC reduction.

2

Zeta potential of Polish copper-bearing shale in the absence and presence of flotation frothers

Peng M., Ratajczak T., Drzymała J.

Mining Science

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2014

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Vol. 21

57--63

EN

In this paper, zeta potential as a function of pH of copper-bearing shale, which is mined in Poland by KGHM, was investigated. The measurements were conducted in water and aqueous solutions of selected flotation frothers. It was established that for investigated copper-bearing shale, after dispersion in water, the isoelectric point (IEP) occurs at pH=3.5. Addition of frothers decreased the IEP on the pH scale and the IEP for butanol was 1.93, for MIBC 2.90 and for eicosaethylene glycol hexadecyl ether (C16E20) 2.76. In the case of introducing frothers changed, the zeta potential becomes less negative. An empirical equation, having two adjustable parameters, was used in the paper to approximate the course of the zeta potential-pH curve. The equation showed a very good approximation of the zeta potential of the investigated shale either in water or frother aqueous solutions.

3

Evaluation of points of zero charge of aluminum oxide reported in the literature.

Kosmulski M.

Prace Naukowe Instytutu Górnictwa Politechniki Wrocławskiej. Konferencje

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2001

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Vol. 95, nr 31

5-14

EN

In 1965 Parks compiled PZC of metal oxides and hydroxides and his paper is still the most frequently cited source of PZC of these materials. The recent compilation (Kosmulski 2001) covers not only oxides and hydroxides, but also mixed oxides, sparingly soluble salts and other materials whose surface charging is pH dependent. One set of data from this compilation (155 PZC of AL2O3 published in 150 papers between 1969 and 2001) was selected to show the effect of crystalline structure on the one hand and of the choice of the experimental method on the other on the PZC. There is no significant difference between the ? form (32 entries, average 8.2, median 8.55) and the ? form (58 entries, average 8.2, median 8.4) and the other forms, mixtures of different forms and materials of unknown structure (65 entries, average 8.3, median 8.7). On the other hand, the choice of the method substantially affects the PZC. The isoelectric point IEP from electroacoustic measurements (11 entries, average 9.3, median 9.5) is significantly above the IEP from classical electrokinetic measurements (78 entries, average 8.2, median 8.7) and potentiometic titration at one ionic strength (29 entries, average and median 8). The results obtained by means of two latter methods are much more scattered than in other methods. The lowest standard deviation was observed in the set of PZC obtained by means of combination of titration (the common intersection point of titration curves for three or more ionic strengths is identified with the PZC) and electrokinetic measurements (7 entries, average and median 8.6), and this value is the "recommended" PZC for alumina.

PL

Parks opublikował w 1965 roku przegląd PZC tlenków I wodorotlenków metali, który do chwili obecnej jest najczęściej cytowanym źródłem informacji. Najnowszy przegląd PZC (Kosmulski 2001) obejmuje nie tylko tlenki i wodorotlenki metali, lecz również tlenki mieszane, trudno rozpuszczalne sole i inne materiały, których ładunek powierzchniowy zależy od pH. Na podstawie przykładowego zestawu danych z tego przeglądu (155 wartości PZC dla Al2O3 opublikowano w 150 pracach w latach 1969-2001) badano wpływ struktury krystalograficznej próbki i doboru metod doświadczalnych na otrzymaną wartość PZC. Stwierdzono brak istotnej różnicy pomiędzy odmianami. Alfa (32 wartości, średnia 8.2, mediana 8.55) i (58 wartości, średnia 8.2, mediana 8.4) oraz innymi odmianami, mieszaninami różnych odmian i materiałami o nieznanej strukturze (65 wartości, średnia 8.3, mediana 8.7). natomiast wartości PZC wyraźnie zależą od zastosowanej metody. Metoda elektroakustyczna (1l wartości, średnia 9.3, mediana 9.5) daje zdecydowanie wyższy punkt izoelektryczny IEP niż klasyczne metody elektrokinetyczne (78 wartości, średnia 8.2, mediana 8.7) i miareczkowanie potencjometryczne przy jednej sile jonowej (29 wartości, średnia i mediana 8). W dwóch ostatnich metodach odchylenie standardowe jest większe niż w pozostałych metodach. Najmniejsze odchylenie standardowe występuje w zbiorze danych otrzymanych przy jednoczesnym zastosowaniu miareczkowania potencjometrycznego (jako PZC przyjmuje się punkt przecięcia krzywych miareczkowania przy co najmniej trzech rożnych siłach jonowych) i pomiarów elektrokinetycznych (7 wartości, średnia i mediana 8.6) i tę wartość można uznać za najbardziej wiarygodną.