title: A comparative study with biologically and chemically synthesized nZVI: applications in Cr (VI) removal and ecotoxicity assessment using indigenous microorganisms from chromium-contaminated site.
abstract: In the present communication, we report a comparative study of Cr (VI) removal using biologically synthesized nano zero valent iron (BS-nZVI) and chemically synthesized nZVI (CS-nZVI), both immobilized in calcium alginate beads. The parameters like initial Cr (VI) concentration, nZVI concentration, and the contact time for Cr (VI) removal were optimized based on Box-Behnken design (BBD) by response surface modeling at a constant pH 7. Under the optimized conditions (concentration of nZVI = 1000 mg L(-1), contact time = ∼ 80 min, and initial concentration of Cr (VI) = 10 mg L(-1)), the Cr (VI) removal by the immobilized BS-nZVI and CS-nZVI alginate beads was 80.04 and 81.08 %, respectively. The adsorption of Cr (VI) onto the surface of alginate beads was confirmed by scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM-EDX), Fourier transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET) analysis. The applicability of the process using both the sorbents was successfully test medium Cr (VI) spiked environmental water samples. In order to assess the ecotoxic effects of nZVI, the decline in cell viability, generation of intracellular reactive oxygen species (ROS), cell membrane damage, and biouptake was studied at 1000 mg L(-1) concentration, with five indigenous bacterial isolates from chromium-contaminated lake sediments and their consortium.
authors.affiliation: Centre for Nanobiotechnology, VIT University, Vellore, Tamil Nadu, 632014, India.
authors.forename: K V G
authors.initials: KV
authors.lastname: Ravikumar
authors.affiliation: Centre for Nanobiotechnology, VIT University, Vellore, Tamil Nadu, 632014, India.
authors.forename: Deepak
authors.initials: D
authors.lastname: Kumar
authors.affiliation: Centre for Nanobiotechnology, VIT University, Vellore, Tamil Nadu, 632014, India.
authors.forename: A
authors.initials: A
authors.lastname: Rajeshwari
authors.affiliation: Department of Chemical Engineering, M. S. Ramiah Institute of Technology, Bangalore, Karnataka, India.
authors.forename: G M
authors.initials: GM
authors.lastname: Madhu
authors.affiliation: Centre for Nanobiotechnology, VIT University, Vellore, Tamil Nadu, 632014, India. pmrudula@vit.ac.in.
authors.forename: P
authors.initials: P
authors.lastname: Mrudula
authors.affiliation: Centre for Nanobiotechnology, VIT University, Vellore, Tamil Nadu, 632014, India.
authors.forename: Natarajan
authors.initials: N
authors.lastname: Chandrasekaran
authors.affiliation: Centre for Nanobiotechnology, VIT University, Vellore, Tamil Nadu, 632014, India. amit.mookerjea@gmail.com.
authors.forename: Amitava
authors.initials: A
authors.lastname: Mukherjee
mesh_terms: D000327:Adsorption; D002857:Chromium / Q000737:chemistry*; D052918:Environmental Restoration and Remediation; D007501:Iron / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D012988:Soil Microbiology; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D062065:Wastewater / Q000737:chemistry; D014874:Water Pollutants, Chemical; D018508:Water Purification
chemical_list: D002857:Chromium; D007501:Iron; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Alginate beads; Biosynthesis; Chromium (VI); Cr (VI) removal; Cytotoxicity; Immobilization of nZVI