▎ 摘　　要

NOVELTY - Violuric acid functionalized reduced graphene oxide (rGO-VA) based nanocomposite adsorbent (I) has an average size of 1.663±0.3 nm. The nanocomposite adsorbent having an amount of 150 mg/L removes up to 99.9% of mercury (Hg), arsenic (As), and lead (Pb) in 0-5 minutes (the required contact 15 time). The nanocomposite adsorbent removes heavy metals Pb2+, Hg2+, As3+/As5+and Co2+ions. USE - Violuric acid functionalized reduced graphene oxide based nanocomposite adsorbent for removing heavy metals like Pb2+, Hg2+, As3+ and Co2+ (claimed). ADVANTAGE - The heavy metal removal efficiency is 99% for Pb2+, Hg2+, As3+ and 85% for Co2+. The adsorbent removes trace amount of metal ions copper (Cu), nickel (Ni), zinc (Zn) and cadmium (Cd). The nanocomposite is stable at lower and higher temperatures and reusability rates till five cycles for the removal of metal ions. DETAILED DESCRIPTION - Violuric acid functionalized reduced graphene oxide (rGO-VA) based nanocomposite adsorbent of formula (I) has an average size of 1.663±0.3 nm. The nanocomposite adsorbent having an amount of 150 mg/L removes up to 99.9% of mercury (Hg), arsenic (As), and lead (Pb) in 0-5 minutes (the required contact 15 time). The nanocomposite adsorbent removes heavy metals Pb2+, Hg2+, As3+/As5+ and Co2+ ions. An INDEPENDENT CLAIM is included for a method for synthesizing rGO-VA nanocomposite via a simple onepot chemical reaction, which involves: a. dispersing graphene oxide (GO) in DMF using bath ultrasonication at 80 hertz (Hz) for 60 minutes to obtain a sonicated mixture; b. adding phosphorus pentachloride to the sonicated mixture followed by continuous stirring at 300 revolutions per minute (rpm), and temperature in the range of 55 to 60℃ for 6 hours to obtain a chlorinated-GO reaction mixture; c. subsequently adding, violuric acid and triethyl amine to the chlorinated-GO reaction mixture while stirring and allowing to continue for 2 hours; d. heating the stirred contents of the mixture and heating at 140℃ for 12 hours to obtain a composite mixture; and e. cooling the composite mixture and washing with ethanol and water by centrifugation to get pure rGO-VA nanocomposite and further drying at predetermined temperature to obtain fine powder of rGO-VA.