title: Specific adsorption of cadmium on surface-engineered biocompatible organoclay under metal-phenanthrene mixed-contamination.
abstract: Bioremediation of polycyclic aromatic hydrocarbons (PAHs) is extremely challenging when they coexist with heavy metals. This constrain has led to adsorption-based techniques that help immobilize the metals and reduce toxicity. However, the adsorbents can also non-selectively bind the organic compounds, which reduces their bioavailability. In this study we developed a surface-engineered organoclay (Arquad®2HT-75-bentonite-palmitic acid) which enhanced bacterial proliferation and adsorbed cadmium, but elevated phenanthrene bioavailability. Adsorption models of single and binary solutes revealed that the raw bentonite adsorbed cadmium and phenanthrene non-selectively at the same binding sites and sequestrated phenanthrene. In contrast, cadmium selectively bound to the deprotonated state of carboxyl groups in the organoclay and phenanthrene on the outer surface of the adsorbent led to a microbially congenial microenvironment with a higher phenanthrene bioavailability. This study provided valuable information which would be highly important for developing a novel clay-modulated bioremediation technology for cleaning up PAHs under mixed-contaminated situations.
authors: Future Industries Institute, University of South Australia, Mawson Lakes Campus, SA 5095, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, ACT Building, University of Newcastle, Callaghan, NSW 2308, Australia. Electronic address: b.nanda.biswas@gmail.com.
authors: Bhabananda
authors: B
authors: Biswas
authors: Future Industries Institute, University of South Australia, Mawson Lakes Campus, SA 5095, Australia; Department of Geological Sciences, Indiana University, Bloomington, IN 47405, USA. Electronic address: binoy.sarkar@unisa.edu.au.
authors: Binoy
authors: B
authors: Sarkar
authors: Indian Council of Agricultural Research (ICAR), Indian Institute of Soil Science, Bhopal, India.
authors: Asit
authors: A
authors: Mandal
authors: Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, ACT Building, University of Newcastle, Callaghan, NSW 2308, Australia; Global Centre for Environmental Remediation (GCER), Faculty of Science and Information Technology, University of Newcastle, Callaghan, NSW 2308, Australia. Electronic address: ravi.naidu@newcastle.edu.au.
authors: Ravi
authors: R
authors: Naidu
mesh_terms: D000327:Adsorption; D002104:Cadmium / Q000737:chemistry*; D019216:Metals, Heavy / Q000737:chemistry; D010616:Phenanthrenes / Q000737:chemistry; D012989:Soil Pollutants / Q000737:chemistry*
chemical_list: D019216:Metals, Heavy; D010616:Phenanthrenes; D012989:Soil Pollutants; D002104:Cadmium
keywords: Bioavailability; Bioremediation; Mixed contamination; Polycyclic aromatic hydrocarbon; Specific adsorption; Surface-engineered organoclay