Elsevier

Carbohydrate Polymers

Volume 146, 1 August 2016, Pages 264-273
Carbohydrate Polymers

Two fold modified chitosan for enhanced adsorption of hexavalent chromium from simulated wastewater and industrial effluents

https://doi.org/10.1016/j.carbpol.2016.03.041Get rights and content

Highlights

  • Ionic solid impregnated phosphated chitosan (ISPC) was synthesized.

  • The material was characterized using FT-IR, TGA-DTA, XRD, SEM, BET and EDX.

  • ISPC has been used for adsorption of Cr(VI) and working parameters were optimized.

  • Adsorption capacity of ISPC towards Cr(VI) was found to be 266.67 mg/g.

  • The material was subjected to column, regeneration and reusability studies.

Abstract

Ionic solid (Ethylhexadecyldimethylammoniumbromide) impregnated phosphated chitosan (ISPC) was synthesized and applied for enhanced adsorption of hexavalent chromium from industrial effluent. The compound obtained was extensively characterized using instrumental techniques like FT-IR, TGA-DTA, XRD, SEM, BET and EDX. ISPC showed high adsorption capacity of 266.67 mg/g in accordance with Langmuir isotherm model at pH 3.0 due to the presence of multiple sites which contribute for ion pair and electrostatic interactions with Cr(VI) species. The sorption kinetics and thermodynamic studies revealed that adsorption of Cr(VI) followed pseudo-second-order kinetics with exothermic and spontaneous behaviour. Applicability of ISPC for higher sample volumes was discerned through column studies. The real chrome plating industry effluent was effectively treated with total chromium recovery of 94%. The used ISPC was regenerated simply by dilute ammonium hydroxide treatment and tested for ten adsorption-desorption cycles with marginal decrease in adsorption efficiency.

Introduction

At present, heavy metal pollution in environment is of great concern towards the health of human beings (Flora, Gupta, & Tiwari, 2012). Chromium is not an omission. Chromium exists in trivalent and hexavalent states. Cr(III) is an essential nutrient for glucose, lipid and protein metabolism in mammals (Mertz, 1976) whereas Cr(VI) is highly toxic. Cr(VI) can easily diffuse in cell membranes and has tendency to cause adverse effect on human health (Katz & Salem, 2006). Exposure to Cr(VI) may lead to skin irritation, kidney, liver and gastric damage. It may cause lung cancer and is known as potential carcinogen. Effluents from various industries such as electroplating, tannery, petroleum, paints and dyeing industries contain Cr(VI) (Ma et al., 2012). Permissible limit of Cr(VI) in drinking water according to WHO guidelines is 0.05 mg/ L (WHO, 1996). Therefore, for detoxification of Cr(VI), there is a need for an affirmative remediation. Conventional methods for the removal of Cr(VI) include chemical precipitation (Mirbagheri & Hosseini, 2005), redox reaction (Ölmez, 2009), mechanical filtration (Muthukrishnan & Guha, 2008), membrane separation (Korus & Loska, 2009), ion exchange (Zhang, Xia, Liu, & Zhang, 2015), and adsorption (Mohan, Singh, & Singh, 2006). Chemical methods require large amounts of chemicals and generate toxic sludge that needs further treatment. The adsorption method is preferred for the removal of heavy metals as it is economically most favourable. Use of biopolymers including cellulose and chitosan is a common practice for chromium detoxification. Properties like biocompatibility, biodegradability and good adsorption tendency enhance the utility of chitosan in pharmaceuticals, waste water treatment, flocculation etc (Alves and Mano, 2008, Dabrowski, 2001, Muzzarelli, 1973, Rinaudo, 2006).

Chitosan has also gained pronounced attention as biosorbents due to its physicochemical properties like chemical stability, high reactivity, excellent chelation behaviour and high selectivity towards pollutants (Elwakeel, 2010a, Elwakeel, 2010b, Owlad et al., 2009). A modification of chitosan mainly involves the free amine group on deacetylated units and hydroxyl groups on C3 and C6 carbons of monomers units. These groups of chitosan can be grafted or crosslinked with organic and inorganic moieties to enhance the adsorption efficiency. Porous chitosan beads (Wan Ngah, Kamari, Fatinathan, & Ng, 2006), crosslinked chitosan beads (Zimmermann, Mecab̂o, Fagundes, Rodrigues, 2010), grafted chitosan (Sharma & Mishra, 2010), chitosan resin (Tan, He, & Du, 2001), magnetic chitosan resin (Elwakeel, 2010a, Elwakeel, 2010b) and chitosan coated onto ceramic alumina (Boddu, Abburi, Talbott, & Smith, 2003) have been reported to show higher adsorption efficiency compared to untreated chitosan. Kahu et al. prepared a sulphate cross-linked chitosan for detoxification of chromium (Kahu, Saravanan, & Jugade, 2014). Anchoring of trialkyl amines on adsorbent has been reported in literature for the solid phase extraction of Cr(VI) (Kalidhasan, Kumar, Rajesh, & Rajesh, 2012; Kumar & Rajesh, 2013; Pinkert, Marsh, Pang, & Staiger, 2009; Shekhawat, Kahu, Saravanan, & Jugade, 2015).

Modification of adsorbent materials is based on two aspects- structural and functional. Both of these have been proved to enhance the adsorption capacity of the materials. In present study, we report two-fold modification on chitosan for admirable adsorption of Cr(VI). It involves crosslinking the polymeric chains with phosphate and functional modification with ionic solid ethylhexadecyldimethylammonium bromide. Crosslinking gives enhanced structural stability and porosity to the material while modification with ammonium salt leads to enhanced ionic interaction with the hydrogen-chromate species.

Section snippets

Materials

Diphenylcarbazide, sodium hydroxide, dipotassium hydrogen phosphate, ethylhexadecyldimethylammonium bromide, and potassium dichromate were procured from Merck, India. Chitosan with molecular weight of 120 kDa and degree of deacetylation 85% was procured from Uniloid Bio-Chemicals India Limited, Hyderabad, India. All the reagents were of analytical grade and used without further purification.

Preparation of ionic solid impregnated phosphated chitosan (ISPC)

2.0 g chitosan powder was taken in a round bottom flask. About 10 mL distilled water was added and 0.1 M

FT-IR spectral analysis

The FT-IR spectral analysis of chitosan (Fig. 1) showed distinct broad peaks corresponding to the Osingle bondH and Nsingle bondH stretching vibrations in the region 3808 cm−1 and 3276 cm−1, the Nsingle bondH bending vibration around 1545 cm−1, Csingle bondN bending vibration at 1374 cm−1and the Csingle bondH and Csingle bondO stretching bands around 2867 and 1017 cm−1 respectively. In ISPC, the peak due to P = O asymmetric stretching appeared at around 1220 cm−1 and Psingle bondO stretching was observed around 926 cm−1 (Amaral, Granja, & Barbosa, 2005). Also, one distinct peak

Conclusion

Modification of a material for enhancement of efficiency is the prime concern from industrial point of view. Dual modification in terms of structural and functional modification in amine group as well as hydroxyl group of chitosan makes it a wonderful material for enhanced adsorption of Cr(VI). The ISPC adsorbent has shown admirable adsorption capacity of 266.67 mg/g for hexavalent chromium which is much higher compared to most of the reported adsorbents. Experimental data showed adsorption

Acknowledgements

We acknowledge University Grants Commission, New Delhi, India for the start-up grant and RTM Nagpur University for University Research Project.

References (58)

  • S. Kalidhasan et al.

    Ultrasound assisted preparation and characterization of crystalline cellulose-Ionic liquid blend polymeric material: a prelude to the study of its application towards the effective adsorption of chromium

    Journal of Colloid and Interface Science

    (2012)
  • I. Korus et al.

    Removal of Cr(III) and Cr(VI) ions from aqueous solutions by means of polyelectrolyte-enhanced ultrafiltration

    Desalination

    (2009)
  • W. Li et al.

    Simultaneous surface functionalization and reduction of graphene oxide with octadecylamine for electrically conductive polystyrene composites

    Carbon

    (2011)
  • W. Mertz

    Chromium and its relation to carbohydrate metabolism

    Medical Clinics of North America

    (1976)
  • S.A. Mirbagheri et al.

    Pilot plant investigation on petrochemical wastewater treatmentfor the removal of copper and chromium with the objective of reuse

    Desalination

    (2005)
  • A.K. Mishra et al.

    Removal of metals from aqueous solution and sea water by functionalized graphite nanoplatelets based electrodes

    Journal of Hazardous Materials

    (2011)
  • D. Mohan et al.

    Trivalent chromium removal from wastewater using low cost activated carbon derived from agricultural waste material and activated carbon fabric cloth

    Journal of Hazardous Materials

    (2006)
  • M. Muthukrishnan et al.

    Effect of pH on rejection of hexavalent chromium by nanofiltration

    Desalination

    (2008)
  • T. Ölmez

    The optimization of Cr(VI) reduction and removal by electrocoagulation using response surface methodology

    Journal of Hazardous Materials

    (2009)
  • I. Qureshi et al.

    Estimation of chromium(VI) sorption efficiency of novel regenerable p-tert-butylcalixareneoctamide, areneoctamide impregnated Amberlite resin

    Journal of Hazardous Materials

    (2009)
  • M. Rinaudo

    Chitin and chitosan: properties and applications

    Progress in Polymer Science

    (2006)
  • K. Sakurai et al.

    Glass transition temperature of chitosan and miscibility of chitosan/poly(N-vinyl pyrrolidone) blends

    Polymer

    (2000)
  • A. Shekhawat et al.

    Synergistic behaviour of ionic liquid impregnated sulphate-crosslinked chitosan towards adsorption of Cr(VI)

    International Journal of Biological Macromolecules

    (2015)
  • P. Suksabye et al.

    Column study of chromium(VI) adsorption from electroplating industry by coconut coir pith

    Journal of Hazardous Materials

    (2008)
  • A.C. Zimmermann et al.

    Adsorption of Cr(VI) using fe-crosslinked chitosan complex (Ch-Fe)

    Journal of Hazardous Materials

    (2010)
  • I.F. Amaral et al.

    Chemical modification of chitosan by phosphorylation: an XPS: FT-IR and SEM study

    Journal of Biomaterials Science, Polymer

    (2005)
  • S. Bhuvaneshwari et al.

    Equilibrium, kinetics: and breakthrough studies for adsorption of Cr (vi) on chitosan

    Chemical Engineering Communications

    (2014)
  • V.M. Boddu et al.

    Removal of hexavalent chromium from wastewater using a new composite chitosan biosorbent

    Environmental Science and Technology

    (2003)
  • G.L. Clark et al.

    X-ray diffraction studies of chitin, chitosan and derivatives

    The Journal of Physical Chemistry

    (1936)
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