Search

U ovom radu ispitivala se ravnoteža sorpcije bakrovih iona na humusu koji nije bio prethodno obrađen. U radu su korištene otopine bakrovog(II) klorid dihidrata različitih koncentracija (2,258 mmol/L; 4,679 mmol/L; 7,556 mmol/L; 10,344 mmol/L; 13,119 mmol/L). Eksperiment se vodio 96 sati, pri temperaturi od 35°C u šaržnim reaktorima. Uspostava ravnoteže, u šaržnom reaktoru, se vodila pri brzini trešnje od 200 okr/min. Za analizu dobivenih rezultata korištene su adsorpcijske izoterme, te se usporedbom eksperimentalnih rezultata s modelima izotermi provjeravalo slaganje modela izoterme s eksperimentalnim podacima. Modeli izotermi koji su korišteni u radu su: Langmuirova, Hillova, Freundlichova i Sipsova izoterma, a eksperimentalni podaci su pokazali najbolje slaganje s Hillovom izotermom. Također, eksperimentalni podaci ukazuju na to da se s porastom početne koncentracije otopine bakrovih iona, količina sorbiranih bakrovih iona u ravnoteži, qe, povećava, a učinkovitost sorpcije, R, smanjuje. In this work the equilibrium of copper ions sorption on untreated humus was studied. Different concentrations of copper (II) chloride dihydrate solutions (2.258 mmol/L, 4.679 mmol/L, 7.556 mmol/L; 10.344 mmol/L, 13.119 mmol/L) were used. The experiment lasted for 96 hours at 35°C and at shaking speed of 200 rpm in batch reactors. For the analysis of the obtained results adsorption isotherms were used. Fitting of the isotherm models with experimental data were obtained by comparing the experimental results with the isotherm models. The isothermal models used are Langmuir's, Hill's, Freundlich's and Sips's and experimental data showed best fit with Hill's isotherm. Also, the experimental data suggested that with the increase of the initial concertation of copper ions, the amount of sorbed copper ions in equilibrium increases, qe, and the efficiency of sorption, R decreases.

Primjenom polarizacijskih metoda i elektrokemijske impedancijske spektroskopije ispitana je mogućnost inhibicije korozije 5052 aluminijske legure (AlMgCr) pomoću askorbinske kiseline (u granicama od 110 -6 do 110 -2 M) u 0.5 M NaCl otopini pri 20 o C. Određeni su korozijski potencijali, korozijska struja, polarizacijski otpor, otpor prijenosu naboja, kapacitet površinskog sloja i difuzija kroz površinski sloj. Izračunata je pokrivenost površine molekulama inhibitora te djelotvornost inhibicije korozije. Dobiveni rezultati su pokazali da askorbinska kiselina učinkovito usporava koroziju AlMgCr legure u kloridnoj otopini uz djelotvornost od  92 %. Nadalje, ustanovljeno je da askorbinska kiselina pripada miješanom tipu inhibitora s pojačanim utjecajem na anodnu reakciju. Mehanizam adsorpcije ispitivanog inhibitora opisan je Frundlichovom adsorpcijskom izotermom. Dobivena vrijednost za standardnu slobodnu energiju adsorpcije u iznosu ≈ -10 kJ mol -1 ukazuje na fizikalnu adsorpciju askorbinske kiseline na površinu AlMgCr legure u NaCl otopini. The corrosion inhibition performance of the ascorbic acid (in range from 110 -6 to 110 -2 M) on 5052 aluminium alloy (AlMgCr) corrosion in neutral 0.5 M solution at 20 o C was investigated using potentiodynamic and electrochemical impedance spectroscopy measurements. Corrosion potential, corrosion current, polarization resistance, charge transfer resistance, capacity of surface layer, and diffusion through the surface layer were determined. The surface coverage of the inhibitor molecules and inhibition efficiency were calculated. The obtained results show that ascorbic acid effectively inhibited the corrosion reaction of AlMgCr alloy in the chloride solution with an inhibition efficiency of up to  92 %. Furthermore, ascorbic acid was found to function essentially as a mixed type with a higher influence on anodic reaction. The adsorption behaviour of investigated inhibitor can be described by the Frundlich adsorption isotherm. The adsorption free energy closes to -10 kJ mol -1 indicates physical adsorption of the ascorbic acid on AlMgCr aluminium alloy surface in NaCl solution.