Adsorption of Pb (II) ions on Variable Charge Oxidic Calcined Substrates with Chemically Modified Surface|重金属吸附数据集|环境科学数据集

The adsorption process is an alternative for treating natural and waste waters, with heavy metals. Oxidic lithological materials, rich in iron and aluminum amphoteric oxides, with pH-dependent surface charges, are a reliable medium for ionic adsorption. Being thermal resistant, these materials can be used to prepare a calcined substrate which is chemically treated in an acid or alkaline medium to enlarge surface positive or negative charge density, being possible anion or cation adsorption from aqueous solution. Oxidic lithological materials use is a low-cost alternative for filtering system because of its availability and easiness preparation and application. Present paper shows results of the adsorption reaction of Pb⁺² ions on calcined substrates prepared with oxidic lithologic material. The study was performed on the substrate with chemically modified surface in alkaline medium as well on non-treated surface. Results show L-type isotherms for the adsorption on the activated substrate, indicative affinity between adsorbate and adsorbent. Average value of k for activated substrate is around 3.7 times greater (1791.73±13.06 with an RSD of 0.72%) compared to the respective average k value for the non-activated substrate (491.54±31.97 with a DER of 6.5%). Protons are produced during the adsorption reaction, 0.35 and 0.26 molH⁺ are produced in the reaction on the activated and non-activated substrate respectively using a 1 mM Pb⁺² solution and y 72.2 and 15.6 molH⁺ using a 10 mM Pb⁺² solution. Acidification agrees with theoretic model of transitional metals chemisorption on amphoteric oxides of Fe, Al, Ti and Mn present in lithological material used for the preparation of adsorbent substrates confirming the information given by the L type isotherms.