Evaluation of efficiency of coagulant obtained from elaborated red sludge from alumina plant

В роботі досліджено ефективність зниження кольоровості та каламутності води річки Дніпро за допомогою існуючих коагулянтів Al2(SO4)3·18 H2O та FeCl3·6 H2O та синтезованого коагулянту із червоного шламу глиноземних заводів (ШК). При проведенні експериментальної частини роботи у лабораторних умовах використовували такі оптимальні дози коагулянтів: 0, 1, 2, 5, 10 мг/дм3 з розрахунку по Al2O3 та Fe2O3. Об’єм проб, що піддавались дослідженням, сягали 200 дм3 . Для моделювання забруднень використовували модельні розчини бентоніту з концентрацією 100 мг/дм3 , гумату натрію з концентрацією 16,8 мг/дм3 , каоліну з концентрацією 100 мг/дм3 та природну воду річки Дніпро. На підставі аналізу отриманих експериментальних даних встановлено, що ШК нічим не поступається існуючим та широко використовуваним коагулянтам. При очищенні та знебарвленні води річки Дніпро ШК показав кращі результати. Тому, можемо сказати, що отримання «альтернативних» коагулянтів із відпрацьованих відходів є цілком перспективним та економічно вигідним напрямком дослідження та розробок нових реагентів водоочищення та водопідготовки.In document, the effectiveness of reducing the chromaticity and turbidity of the Dnipro river water was investigated and estimated by means of existing coagulants Al2(SO4)3·18H2O and FeCl3·6H2O and synthesized coagulant from the red sludge of alumina plants - SC. During the experimental part of the work in the laboratory, the following optimal dosages of coagulants were chosen, namely, 0, 1, 2, 5, 10 mg/dm3 based on Al2O3 and Fe2O3. The volume of samples of the solutions, which were subjected to the study, reached 200 ml. Model solutions of bentonite with a concentration of 100 mg/dm3 , sodium humate with a concentration of 16.8 mg/dm3 , kaolin concentration of 100 mg/dm3 and natural water of the Dnipro River were used. Based on the analysis of the experimental data obtained, it was found that the alternative coagulant is not inferior to the existing and widely used coagulants. During clearing and discoloration of the Dnipro river waters, the SC showed better results. Therefore, it can be said that obtaining "alternative" coagulants from waste products is a very promising and economically viable direction of research and development of new reagents for water purification and water treatment

Study of Effectiveness of Heavy Metals Ions as the Inhibitors of Steel Corrosion

The effect of ions of d-metals on the processes of corrosion in a movable and immovable neutral aqueous environment has been investigated. It was shown that a number of ions, such as zinc, chromium, lead, under conditions of high aeration and temperature of 20 ºС at concentrations of 2−5 mg/dm3, are effective inhibitors of steel corrosion. This is due to the formation of a passivation oxygen film on the surface of metal. The degree of corrosion protection is maintained at the level of 80−90 %. In the case of elevating the temperature to 50 ºС, a significant (up to 40 %) decrease in the inhibitory properties of ions of d-metals is observed. This is due both to the destabilization of the oxygen passivation film and the growth of oxidation rate of steel with increasing temperature.It was demonstrated that phosphonic acids, such as oxyethyldidiphosphone acid, nitrilotrimethylphosphonium acid, due to the interaction of complexons with the surface of metals, stabilize the passivation oxygen film, providing a degree of protection against corrosion at 95−98 % at acid dose of 10 mg/dm3. However, when the temperature rises to 50 °C, a protective effect is reduced.It was established that the use of compositions based on OEDPhA/NTMPhA and Zn/Pb/Cr ions in the range of temperatures 20−50 oC provides a degree of protection of steel from corrosion at the level of 90 %. This is explained by the formation of three-dimensional complexes of phosphonic acids with metal ions and corroded iro