Facile synthesis and characterization of metakaolin/carbonate waste-based geopolymer for Cr(VI) remediation: Experimental and theoretical studies

•Dolomite waste/metakaolin-based geopolymer was employed as a low-cost adsorbent for Cr(VI) removal at different temperatures.•The developed geopolymer with 15 wt. % MK offered the highest compressive strength.•Statistical physics models were utilized to understand the Cr(VI) adsorption mechanism.•The Cr(VI) adsorption capacities extended from 42.49 to 50.44 mg/g.•Thermodynamic parameters explained the spontaneous nature of Cr(VI) adsorption.