title: Optimization of isotherm models for pesticide sorption on biopolymer-nanoclay composite by error analysis.
abstract: A carboxy methyl cellulose-nano organoclay (nano montmorillonite modified with 35-45 wt % dimethyl dialkyl (C14-C18) amine (DMDA)) composite was prepared by solution intercalation method. The prepared composite was characterized by infrared spectroscopy (FTIR), X-Ray diffraction spectroscopy (XRD) and scanning electron microscopy (SEM). The composite was utilized for its pesticide sorption efficiency for atrazine, imidacloprid and thiamethoxam. The sorption data was fitted into Langmuir and Freundlich isotherms using linear and non linear methods. The linear regression method suggested best fitting of sorption data into Type II Langmuir and Freundlich isotherms. In order to avoid the bias resulting from linearization, seven different error parameters were also analyzed by non linear regression method. The non linear error analysis suggested that the sorption data fitted well into Langmuir model rather than in Freundlich model. The maximum sorption capacity, Q0(μg/g) was given by imidacloprid (2000) followed by thiamethoxam (1667) and atrazine (1429). The study suggests that the degree of determination of linear regression alone cannot be used for comparing the best fitting of Langmuir and Freundlich models and non-linear error analysis needs to be done to avoid inaccurate results.
authors.affiliation: Division of Agricultural Chemicals, ICAR-Indian Agricultural Research Institute, New Delhi 110012, India. Electronic address: neethu853@gmail.com.
authors.forename: Neethu
authors.initials: N
authors.lastname: Narayanan
authors.affiliation: Division of Agricultural Chemicals, ICAR-Indian Agricultural Research Institute, New Delhi 110012, India.
authors.forename: Suman
authors.initials: S
authors.lastname: Gupta
authors.affiliation: Division of Agricultural Chemicals, ICAR-Indian Agricultural Research Institute, New Delhi 110012, India.
authors.forename: V T
authors.initials: VT
authors.lastname: Gajbhiye
authors.affiliation: Division of Soil Science and Agricultural Chemistry, ICAR-Indian Agricultural Research Institute, New Delhi 110012, India.
authors.forename: K M
authors.initials: KM
authors.lastname: Manjaiah
mesh_terms: D000327:Adsorption; D001280:Atrazine / Q000737:chemistry / Q000378:metabolism; D001546:Bentonite / Q000737:chemistry / Q000378:metabolism; D001704:Biopolymers / Q000737:chemistry* / Q000378:metabolism; D007093:Imidazoles / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008962:Models, Theoretical; D053761:Nanocomposites / Q000737:chemistry*; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000737:chemistry / Q000378:metabolism; D010078:Oxazines / Q000737:chemistry / Q000378:metabolism; D010575:Pesticides / Q000737:chemistry* / Q000378:metabolism; D000077922:Thiamethoxam; D013844:Thiazoles / Q000737:chemistry / Q000378:metabolism; D014961:X-Ray Diffraction
chemical_list: D001704:Biopolymers; D007093:Imidazoles; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010078:Oxazines; D010575:Pesticides; D013844:Thiazoles; D001546:Bentonite; C082359:imidacloprid; D000077922:Thiamethoxam; D001280:Atrazine
keywords: Biopolymer-nanoclay composite; Error analysis; Linear; Non linear regression; Pesticides; Sorption