Izračun porazdelitve elektrolita med izotropno raztopino in nabito režo

Zrnić, Sanja (author), Reščič, Jurij (mentor)

Z računalniškimi simulacijami Monte Carlo sem izračunala kemijski potencial izotropnega 1:1 elektrolita v območju koncentracij med 0,02M do 1M. Z isto metodo sem izračunala tudi kemijski potencial istega elektrolita, ki se nahaja v nabiti reži. Hotela sem ugotoviti, kako naboj na stenah reže vpliva na koncentracijo soli v reži ter tudi, kakšna je struktura raztopine v njej. Ioni so bili v našem primeru toge kroglice, ki so imele nabojv središču. Spreminjala sem površinsko gostoto naboja na stenah reže, njeno širino in koncentracijo soli v njej. Z večanjem površinske gostote naboja na stenah reže se je kemijski potencial elektrolita v njej zmanjševal. Na osnovi enakosti kemijskega potenciala elektrolita v reži s kemijskim potencialom izotropnega elektrolita sem določila koncentracijo soli v reži, ki je v ravnotežju z izotropno raztopino. V nabiti reži je koncentracija elektrolita večja kot v izotropni raztopini. Ta razlika se veča z naraščanjem površinske gostote naboja. Ob stenah reže je močno povečana koncentracija ionov nasprotnega predznaka, medtem ko se ioni enakega predznaka nahajajo v osrednjem delu reže.

• Language: Slovenian
• Keywords: kemijski potencial, Monte Carlo, izotropna raztopina
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2020
• PID: 20.500.12556/RUL-121073
• COBISS.SI-ID: 36298755
• Publication date in RUL: 29.09.2020

Secondary language

• Language: English
• Title: Calculation of the electrolyte distribution between isotropic solution and charged slit

Abstract

A chemical potential of a bulk 1:1 electrolyte was calculated using Monte Carlo computer simulations in the concentration range from 0.02M to 1M. The same method was used to determine the chemical potential of 1:1 electrolyte confined in a charged slit. The goal was to determine the effect of surface charge densitiy on salt concentration in the slit. Ions were modeled as charged hard spheres. Slit width, surface charge density, and salt concentration were varied. With increasing surface charge density a chemical potential of the salt was lowered. Based on the equality of the chemical potential, the salt contentration in the slit in equilibrium with bulk electrolyte was determined. In the charged slit the salt concentration is larger than in the bulk. This excess increases with increasing surface charge density. Near the slit walls there is significantly increased concentration of ions of the opposite sign, while ions of the same sign repelled toward the slit center.

• Keywords: chemical potential, Monte Carlo, isotropic solution