Electronic Supplementary Material

Nanocellulose for biosorption of chlorpyrifos from water: Chemometric optimization, kinetics and equilibrium

Pareshkumar G Moradeeyaa, Madhava Anil Kumara, Ravi B Thorata, Manali Rathoda,b, Yasmin Khambhatyc, and Shaik Bashad*

aMarine Biotechnology and Ecology Division, CSIR-Central Salt & Marine Chemicals Research Institute (CSIR-CSMCRI), Bhavnagar 364 002, Gujarat, India.

bAcademy of Scientific and Innovative Research (AcSIR), CSIR-CSMCRI, Bhavnagar 364002, Gujarat, India.

cLeather Process Technology Division, CSIR-Central Leather Research Institute, Adyar, Chennai 600 020, Tamil Nadu, India.

dHyderabad Zonal Centre, CSIR-National Environmental Engineering Research Institute, IICT Campus, Tarnaka, Hyderabad 500 007, Telangana, India.

*Corresponding Author: (Shaik Basha) Telefax: +91-40-27160639,

E mail:

Experimental Methods

Optimization of biosorption experiments

The optimization tool employs the evaluation of the response, biosorption (%)based on the different combinations of parameters such as NC (g/L), initial CP concentration (mg/L) and contact time (min). The coded (dimensionless) variables in the CCD matrix were related by the equation given below:

(1)

where X0denotes the coded values Xi at the centre point and δX is the step change. The chosen factors for optimization were related to the response by the quadratic equation given below;

(2)

where Y is the response, β0, βj, βjj and βij are the regression coefficients for the intercept, linear, quadratic and interaction effects respectively and Xi, Xjare coded independent variable. The aforementioned polynomial equation was validated by performing biosorption experiments with the optimal conditions.The statistical significance and goodness-of-fit of the developed model were evaluated by R2, R2adjusted and by the Student’s t-distribution, Fisher’s variance ratio (F-ratio), P-value and analysis of variance (ANOVA). The three dimensional (3D) response surface plots were generated to understand the interaction of the independent factors and to find the optimal levels for the enhanced CP biosorption.

Characterization of NC

The morphology of the NC was characterized bytransmission electron microscopy (TEM, JEOL JEM-2100) with acceleration voltage of 200 keV and atomic force microscopy (NT-MDT, NTEGRA, TS 150, Russia)with integrated software Nova Px 3.2.5 12501.Powder X-ray diffraction (XRD) patterns were obtained (EMPYREAN X-Ray Powder Diffractometer, The Netherlands) using Cu-Kα radiation (λ= 1.5406Å). Thermogravimetry measurement (TG/DTG, Mettler-Toledo TGA/SDTA System 851 thermal analyzer) was conducted from 25 to 400°C at a heating rate of 20°C/min in N2 atmosphere.Fourier transform-infrared (FT-IR) absorption spectra were recorded using a FT-IR spectrometer (FTIR GX 2000, Perkin-Elmer, USA) equipped with a KBr beam splitter (KBr, FTIR grade) at room temperature. The spectra were recorded over the wave number range of 400-4000cm−1 with 10 scans at a resolution of 4cm−1.

Table S1. CCD matrix for the operational parameters and corresponding biosorption (%)

Run / NC (g/L) / CP (mg/L) / Time (min) / Biosorption (%)
1 / 1.0 / 5.0 / 10 / 93.17
2 / 2.0 / 5.0 / 10 / 90.48
3 / 1.0 / 15 / 10 / 96.47
4 / 2.0 / 15 / 10 / 98.44
5 / 1.0 / 5.0 / 30 / 94.48
6 / 2.0 / 5.0 / 30 / 96.76
7 / 1.0 / 15 / 30 / 3.43
8 / 2.0 / 15 / 30 / 3.81
9 / 1.0 / 10 / 20 / 20.28
10 / 2.0 / 10 / 20 / 22.88
11 / 1.5 / 5.0 / 20 / 99.31
12 / 1.5 / 15 / 20 / 2.28
13 / 1.5 / 10 / 10 / 25.89
14 / 1.5 / 10 / 30 / 28.32
15 / 1.5 / 10 / 20 / 20.47
16 / 1.5 / 10 / 20 / 20.47
17 / 1.5 / 10 / 20 / 20.47
18 / 1.5 / 10 / 20 / 20.47
19 / 1.5 / 10 / 20 / 20.47
20 / 1.5 / 10 / 20 / 20.47
Fig. S1. AFM of NC(a) height image, (b) 3D view, obtained from ICAR-CIRCOT, Mumbai

Fig. S2.XRD pattern of NC obtained from ICAR-CIRCOT, Mumbai

Fig. S3. TGA of NC obtained from ICAR-CIRCOT, Mumbai

Fig. S4. FT-IR spectra of (A) NC and (B) CP biosorbed NC

Fig. S5. Biosorption isotherms of CP onto NC at various temperatures (pH: 7.4, dose: 1.5 g/ L, agitating rate: 120 rpm, contact time: 300 min).

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