Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras

OPTICAL SENSOR FOR HEXAVALENT CHROMIUM

Technology Category/Market

Technology: Optical Sensor f​or heavy metal ions  Industry: Healthcare, Food, Chemical, Manufacturing Leather, Mining. Applications: Drinking & wastewater quality monitoring, Blood testing, Environmental compliance and law enforcement agencies

Market: The global optical sensors market is projected at a CAGR of 6.33% during period of 2023-2028.

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Problem Statement

  • In present era, Chromium is a widely used heavy metal, because of which hexavalent chromium ions are hazardous pollutants frequently found in natural resources water.
  • Conventional techniques for Cr6+ detection & quantification by means of the standard methods using atomic absorption spectrometry or mass spectrometry are limited by requirement of expensive infrastructure & skilled personnel including other issues.
  • Hence, there is a need to introduce present method which mitigate above challenges.

Technology

  1. Present invention discloses a method of fabricating a silica optical probe for Cr6+ detection.
  2. Further, said invention discussed an optical probe which comprises a U-bent silica optic fiber probe having a first end, a second end & a U-bent region, which is applicable for detecting Cr6+.
  3. Further, said optical probe includes a metal organic framework (MOF) called zeolite imidazole (ZIF-67) coated on an outer surface of the U-bent region shown in below figures.
  • The method comprises a few steps explained in smart chart & Fig herein
  • 1st Step explains about Fabricating a U-bent silica optic fiber probe
  • 2nd Step explains about Activating an outer surface of the U-bent region to generate hydroxyl groups on the
  • surface
  • 3rd Step explains about Growing a metal organic framework (MOF) and Providing post-thermal treatment to the coated probe
  • The invention describes about the chemical synthesis of ZIF-67, using 2-methyl imidazole & cobaltous nitrate hexahydrate shown in figures herein below.
  • The aqueous solution of both chemicals is mixed in certain molarity & this freshly prepared growth mixture solution is used for the in-situ growth of thin films on U-bent silica optical fiber illustrates in figure.

Key Features/Value Proposition

Technical Perspective:

  • ZIF-67 selectively entrap Cr6+ ions and the high EWA sensitivity of the U-FOS allows specific detection of Cr6+ ions by means of their intrinsic optical absorption around 395 nm.
  • The MOF coated fiber probes are stable over a month even in humid and at room temperature.
  • The claimed sensor demonstrates high selectivity for chromium ion detection with respect to other potential interfering heavy metal ions present in water such as Mn7+, Fe3+, Co2+, Cl , Cu2+,Pb2+, Hg2+, Mg2+, Ca2+ , Ni2+, Cd2+, Zn2+, Li+.
  • The proposed synthesis method is advantageous for many applications where fresh water may be used as medium for sensing.

Industrial Perspective:

  • The ZIF-67 coated U-FOS Cr6+ sensor realized with a portable LED-photodetector set-up demonstrates a wide dynamic range & useful detection limits.
  • Potentiality applicable to develop the U-FOS as a portable on-field sensor, or applicable to any other handheld device.
Questions about this Technology?

Contact for Licensing

Research Lab

Biosensors Lab-Prof. Raghavendra Sai V.V

Department of Applied Mechanics and Biomedical Engineering

Intellectual Property

  • IITM IDF Ref.:2147
  • Patent No. 202141023371
  • PCT Application No. PCT/IN2022/050375

Technology Readiness Level

TRL-4/5

Proof of Concept ready, tested & validated

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