NITROGEN ENRICHED NANOPOROUS POLYTRIAZINES FOR ENERGY AND ENVIRONMENTAL APPLICATIONS

Abstract

The profound interest of the author in the areas of “energy and environment” led to carry out research during this doctoral work related to the development of high surface area polymeric materials for abatement of pollution in air and water as well as in the area of energy storage. Thorough literature studies indicated a strong relationship between the performance of the polymeric materials with the textural properties and presence of heteroatoms. Thus, in this research it is intended to synthesize nanoporous high surface area polymeric materials with hierarchical pore structure that are rich in nitrogen. For this, various synthetic approaches such as conventional heating, solvothermal, sonochemical and microwave assisted methods have been utilized for condensing two of the inexpensive precursors, melamine and cyanuric chloride, that are very rich in nitrogen. All the specimens have been investigated extensively using state of the art characterization techniques. Among these, the condensation is complete only in the specimens made by microwave assisted method. By optimizing the synthesis conditions, NENP-1, the best material, was made within 30 min at 140 °C with a microwave power of 400 W, when 1 mmol of each of the precursors were dissolved in 20 ml DMSO. The SABET of 840 m2 g1 and hierarchical PSD centred 1.3 and 3.8 nm along with high N content of 50 wt% drove the NENP-1 to achieve large CO2 capture capacity of 22.9 wt% at 0 °C and 1 bar. The H2 and CH4 storage capacities are 2.3 and 1.8 wt% at 196 °C and 0 °C, respectively, at 1 bar. Pre-carbonization at 350 °C further improved the CO2 capture capacity to 33.8 wt% and H2 storage capacity to 2.4 wt%. As an active electrode material for supercapacitor, the NENP-1 has shown high Csp of 1256 F g1 @ 1 mV sec1. An asymmetric supercapacitor device fabricated using NENP-1 has high energy density of 102 Wh kg1 at 1.6 kW kg1, could lit 1.5 V red and green LEDs, and 3.0 V blue LED up to 11, 4 and 0.5 min, respectively, on charging for 30 s at 3.0 V. The NENP-1 as an organocatalyst efficiently catalyses the Knoevenagel reaction for C-C bond formation with high yield (~98%) in a short reaction time of 30 min at RT. Its uranium adsorption capacity of 489 mg g1 (97.8% efficiency) at 25 °C and pH of 7 and its ability to satisfy the WHO (0.015 mg l1) and USEPA (0.03 mg l1) permissible limits along with the adsorption of uranium from simulated seawater conditions made it an efficient adsorbent for uranium removal and enrichment. All these properties and applications made this research successful as planned and designed at the beginning of the research.