title: Aluminosilicate-based adsorbent in equimolar and non-equimolar binary-component heavy metal removal systems.
abstract: Cadmium (Cd) and lead (Pb) are toxic heavy metals commonly used in various industries. The simultaneous presence of these metals in wastewater amplifies the toxicity of wastewater and the complexity of the treatment process. This study has investigated the selective behavior of an aluminosilicate-based mesoporous adsorbent. It has been demonstrated that when equimolar quantities of the metals are present in wastewater, the adsorbent uptakes the Pb²⁺ ions selectively. This has been attributed to the higher electronegativity value of Pb²⁺ compared to Cd²⁺ which can be more readily adsorbed on the adsorbent surface, displacing the Cd²⁺ ions. The selectivity can be advantageous when the objective is the separation and reuse of the metals besides wastewater treatment. In non-equimolar solutions, a complete selectivity can be observed up to a threshold Pb²⁺ molar ratio of 30%. Below this threshold value, the Cd²⁺ and Pb²⁺ ions are uptaken simultaneously due to the abundance of Cd²⁺ ions and the availability of adsorption sites at very low Pb²⁺ molar ratios. Moreover, the total adsorption capacities of the adsorbent for the multi-component system have been shown to be in the same range as the single-component system for each metal ion which can be of high value for industrial applications.
authors.affiliation: Chemical and Biomolecular Engineering Department, Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong SAR E-mail: kemckayg@ust.hk.
authors.forename: Meng
authors.initials: M
authors.lastname: Xu
authors.affiliation: Chemical and Biomolecular Engineering Department, Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong SAR E-mail: kemckayg@ust.hk; School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Hong Kong SAR.
authors.forename: Pejman
authors.initials: P
authors.lastname: Hadi
authors.affiliation: Chemical and Biomolecular Engineering Department, Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong SAR E-mail: kemckayg@ust.hk.
authors.forename: Chao
authors.initials: C
authors.lastname: Ning
authors.affiliation: Chemical and Biomolecular Engineering Department, Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong SAR E-mail: kemckayg@ust.hk.
authors.forename: John
authors.initials: J
authors.lastname: Barford
authors.affiliation: School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Hong Kong SAR.
authors.forename: Kyoung Jin
authors.initials: KJ
authors.lastname: An
authors.affiliation: Chemical and Biomolecular Engineering Department, Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong SAR E-mail: kemckayg@ust.hk; Division of Sustainable Development, College of Science, Engineering and Technology, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar.
authors.forename: Gordon
authors.initials: G
authors.lastname: McKay
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry / Q000378:metabolism*; D002104:Cadmium / Q000378:metabolism*; D000075322:Heavy Metal Poisoning; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000378:metabolism*; D008956:Models, Chemical; D011041:Poisoning / Q000517:prevention & control*; D016062:Porosity; D017550:Spectroscopy, Fourier Transform Infrared; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification / Q000379:methods* / Q000592:standards
chemical_list: D000538:Aluminum Silicates; D002104:Cadmium; D007854:Lead; D062065:Wastewater; C049037:aluminosilicate