Comparison of dynamics and monotonic titrations as methods for determination of anionic surfactants in effluents

Abstract

Tenzidi su organski spojevi koji na jednom kraju molekule imaju hidrofobnu ili lipofilnu grupu, a na drugom kraju molekule imaju hidrofilnu ili lipofobnu grupu. To su tvari koje snižavaju površinsku napetost, a pri određenim koncentracijama u otopini, kada se postigne kritična micelarna koncentracija (CMC) formiraju se u micele. Dijele se na kationske, neionske, anionske i amfolitske, a zbog njihove široke primjene u raznim područjima potrebno je vrlo brzo i točno odrediti njihovu koncentraciju u proizvodima i otpadnim vodama. Najčešće korištena metoda za određivanje njihove koncentracije je potenciometrijska titracija. U eksperimentalnom dijelu rada određene su koncentracije anionskih tenzida u standardnoj otopini anionskog tenzida te u tri različita uzorka otpadnih voda, koristeći dvije metode potenciometrijske titracije: dinamičku i monotonu titraciju. Rezultati su uspoređeni kako bi se ispitalo postoji li razlika u mjerenjima pri određivanju točke ekvivalencije te koja metoda je preciznija i zašto.Surfactants are organic compounds that have a hydrophobic or lipophobic group on one end of the molecule and a hydrophilic or lipophilic group at the other. They are substances that reduce surface tension and at certain concentration in the solution, when the critical micellar concentration (CMC) is achieved, they form micelles. They are divided into cationic, nonionic, anionic and ampholitic. Due to their wide application in different areas, it is necessary to determine their concentration in products and effluents fast and accurate. The most commonly used method for determining their concentration is potentiometric titration. In the experimental part, anionic surfactant concentrations were determined in the standard anionic surfactant solution and in three different wastewater samples using two potentiometric titration methods: dynamic and monotonic titration. The results were compared to see if there is a difference between the measurements in equivalence point determination and which method is more precise and why