Experimental investigation of sodium ion adsorption on polyacrylic acid grafted graphene oxide polymeric adsorbent: Kinetics, isotherms, and performance analyses

In this study, the sodium ion adsorption, as a desalination process of saline water, on polyacrylic acid grafted on graphene oxide (PAA-g-GO) was investigated. According to the results of GPC and FTIR analyses, it was confirmed that the synthesized adsorbent has a very effective function for Na+ adsorption. The remarkable finding about the synthesized adsorbent was that in all the tested pH range (8–10) and sodium ion concentrations (0.1–1 M), the measured adsorption capacities were reported to be more than 1750 mg/g. However, it is interesting that the maximum adsorption capacity was obtained a significant amount of 7462.31 mg/g at pH =10. According to the adsorption kinetics analysis results, the equilibrium time was obtained about 90 min. Also, by examining the effect of pH on the amount of sodium ion adsorption, it was found that it increased by increasing pH value. Adsorption data were also modeled with the Redlich-Peterson isotherm with R2 greater than 0.99 for all range of examined pHs. By examining the effect of adsorbent dosage on Na+ adsorption, it was found that the effect of the adsorbent dosage was very high at low initial concentrations (0.1 to 0.2 M), but this effect decreased by increasing the dosage. [Display omitted] •Poly acrylic acid was successfully grafted on graphene oxide (PAA-g-GO) as a new sodium ion adsorbent.•PAA-g-GO demonstrated exceptional sodium adsorption capacity, reaching 7462.31 mg/g at pH 10 and 1 M initial concentration.•The adsorbent exhibited a relatively short equilibrium time, indicating fast sodium ion adsorption.