Мuzafarova S., Adilova K.M., Niyazova M.M.
Tashkent chemical-technological Institute, Uzbekistan
Лечение ооо ” maxam-chirchik ” от сточные воды ионов тяжелых металлов
“MAXAM-CHIRCHIK” да оқава сувларни оғир металларнинг ионларидан тозалаш
Production of mineral fertilizer is one of the most intensively developing branches of industry in the Republic of Uzbekistan. At the same time the production capacity increasing of mineral fertilizer, diversification and its upgrading are connected with the increasing of sewage water capacity with such heavy metals as copper, zinc, nickel, chrome.
The technological scheme of sewage treatment from heavy metals consists of averaging of incoming drains, processing with reagents in order to conversion to nonsolite form and the sedimentation of generated fractions in settling tanks and sludge dehydrating. In this case there is produced much sludge which has bad sedimental characteristics and is separating from water difficultly. The process of sedimentation in settle tanks lasts 5 hours. To accelerate the sedimentation process there is used effective reagents flocculants which promote large and quickly settling flocks formation. In the capacity of flocculants there may be used water-soluble and high molecular surfactant species which have certain sets of hydrophile groups in their structure – amide, carboxyl, hydroxyl, and also hydrophobic groups stipulating the activity in interphase boundary. The aim of this research was production and analysis polyelectrolyte characteristics and high molecular surfactant species on the base of heteropolymer of sterol with maleic anhydride and also finding the possibilities of their using as flocculants in treatment of “Maxam-Chirchik” Ltd. sewage water from heavy metals. Water-soluble polymers were taken by amidation of heteropolymer of sterol with maleic anhydride monoethanolamine, and also by etherification of heteropolymer with aliphatic alcohol (for example, butyl, decyl) in organic place and the following amidation with monoethanolamine in water-organic place at 2980С. Received heteropolymers are called МSМ,МSМ-4, МSМ-8, МSМ-10 and contain from hydrophobic phenylic radicals in each elementary link and lateral hydrocarbon radicals (for example, butyl, decyl), and also hydrophile amide, carboxyl and hydroxyl groups in the line of polymer chain. In contrast to ordinary polyelectrolyte they have not only polyelectrolyte but also surfactant species characteristics in interphase boundary. Flocculating characteristics of heteropolymers were explored for sewage water with heavy metals as copper, zinc, nickel, chrome. According to the technological scheme these metals are conversed into nonsolite form by special reagents – sodium sulfide, ferrick sulphate, calcium carbonate or by galvanic coagulation method with broken iron and coke. During this process there are forming quantities of fine-crystalline sediments with bad sedimental characteristics. Time of natural brightening is 15-20 hours. It’s necessary to add coagulants and flocculants for intensification of settling process in order to enlarge disperse particles and to promote their quick sedimentation. Flocculating characteristics of heteropolymers were explored by definition speed of settling the suspension from sewage water versus to add-on flocculant concentration and to solution pH. Thereto there were taken 30 ml of sewage water put into graduated cylinders, turbidity of which was previously defined on Snellen device. Then definite quantity of flocculants were added in each cylinders as 0,1% water solution. After adding the reagents the contents of cylinders were carefully mixed and let to rest for 20 minutes. During that time flocks forming and settling were observed. After full settling the capacity of the sediment and sewage water turbidity were measured. The brightening effect of sewage water was defined before and after the sedimentation. As seen from findings below the heteropolymers ability to flocculation is growing with the length increasing of lateral hydrocarbon radicals, that is the increasing of their interphase boundary. Thus, for example, it’s 90-94% of the for the heteropolymer with 10 atoms in lateral hydrocarbon chain. Table
Kinetics of solid particles settling from sewage water in flocculation process
|The capacity of sediment, %, at the settling time (min)||Residual quantity of suspended particle, %||Brightening effect, %|
The comparison of flocculating characteristics of heteropolymers with the ordinary polyelectrolytes shows that the hydrophobic radicals presence promotes quicker linking the disperse particle and forming them into aggregates. Seemingly it’s explained by the fact that further to electrostatic adhesion of the disperse particles to the functional groups of flocculant there is a process of their bonding at the expense of interaction effect between the hydrophobic radicals and solid particles.
Thereby according to findings it’s clear that the high molecular surfactant species can be successfully used as effective reagents for treatment of industrial sewage water with heavy metals, and the flocculate ability grows with the increasing of activity in interphase boundary.