Synthesis of CuSiO3-loaded P-doped porous biochar derived from phytic acid-activated lemon peel for enhanced adsorption of NH3

Ammonia (NH3) is a typical malodorous pollutant and one of the key factors causing PM2.5. It is of great significance to develop an efficient material with outstanding adsorption ability for NH3 capture. Herein, a novel CuSiO3/PBC composite adsorbent is fabricated by first producing phosphorous-doped porous biochar (PBC) via pyrolysis of lemon peel with phytic acid as both the phosphorous source and activator, and subsequent loading of cupric silicate (CuSiO3) onto the PBC with an ultrasonic dipping process. Among these as-fabricated composites, the CuSiO3/PBC-2-500-0.2 adsorbent (where 2 = the mass ratio of phytic acid to LP; 500 = the activation temperature; 0.2 = the atomic percentage of Cu) with a large surface area of 726.3 m(2) g(-1) delivers an excellent NH3 batch adsorption ability of 6.36 mmol g(-1) at 298 K and 1 bar, and a high dynamic adsorption ability of 1.96 mmol g(- 1) under 200 ppm NH3 and a total flow rate of 50 mL min(-1). The CuSiO3/PBC-2-500-0.2 composite also maintains circa 80% of the initial adsorption capacity after 8 cycle reuses, conducive to continuous operation. Furthermore, the postulated adsorption mechanism is demonstrated that NH3 reacts with acidic sites such as H+ of HPO42- to form NH4(+) and forms [Cu(NH3)(4)](2+) with Cu2+, and the porous structure of the composite material also plays an important role. This work not only provides a promising adsorbent for NH3 capture, but also displays a novel idea for the development of excellent composite adsorbents derived from biomass waste.

Automated summary

A novel CuSiO3/PBC composite adsorbent with excellent NH3 adsorption capacity and reusability was fabricated in this study, providing a promising adsorbent for NH3 capture and demonstrating a new idea for the development of excellent composite adsorbents derived from biomass waste.