Dredged-Sediment-Promoted Synthesis of Boron-Nitride-Based Floating Photocatalyst with Photodegradation of Neutral Red under Ultraviolet-Light Irradiation

Abstract

A novel floating photocatalyst (BN-DS-7) has been successfully synthesized by calcining the mixture of boron nitride (BN) and dredged sediment (DS) with a specific mass ratio (3:7) at 1100 °C for a half hour. BN is synthesized for the first time using an oxygen-limited method, which consists of a nanoplate ∼30 nm in size and has a bandgap at 3.94 eV. The as-synthesized BN can degrade NR under ultraviolet (UV) light irradiation. For BN-DS-7, X-ray photoelectron spectroscopy analysis suggests that BN mainly interacts with DS through the strong coordination between these N atoms in BN and these Si and Al atoms in DS. This leads to BN-DS-7 having good compression strength (∼9 MPa). Thermogravimetric analysis for BN shows that a few BN (∼13%) synthesized via an oxygen-limited method will pyrolyze at 1100 °C and the released gas can be sealed in the inside of DS at 1100 °C, resulting in that BN-DS-7 can float on the water surface. Photodegradation results show that BN-DS-7 can degrade 84% of NR (20 mg/L) under UV-light irradiation for 5 h, and the active species are •OH and photoinduced hole. Total organic carbon analysis for NR solution before and after photodegradation show that ∼70% of NR has been mineralized into inorganic carbons. This work is helpful to develop a new type of BN-based floating material and enlarge the application field of DS.

Incorporating p‐Phenylene as an Electron‐Donating Group into Graphitic Carbon Nitride for Efficient Charge Separation

“…[34] To understand the experimentalo bservations, DFT calculations at the B3LYP/6-31(d) level of theory with the Gaussian 03 package were performed on fragment PCN and CN-x models (Scheme 1). [35] The effects of bridging p-phenylene on the band structure and electronic structure of PCN were investigated. The incorporation of p-phenylene in PCN upshifts the energy level of the HOMO from À6.2 to À6.1 eV (Figure 7a), while the energy level of the LUMO is unaltered.…”

“…The dry mixed powder was put into ac rucible with ac over and then heated to 400 8Cina muffle furnace for 2hat ah eating rate of 5 8Cmin À1 .A fter cooling to room temperature, the as-synthesized yellow product was milled into ap owder.M aterials for which 0.054, 0.27, 1.35, and 2.7 mg were mixed with 1gpreheated material were denoted CN-0.054, CN-0.27, CN-1. 35, and CN-2.7, respectively.B enzoquinone (BQ)-modified carbon nitride was also prepared by the same procedure as above, but with the use of 0.29 mg of BQ instead of 0.27 mg of p-phenylenediamine, and the final material was denoted CN-BQ. For comparison, 1gof the material preheated at 520 8C was directly heated to 400 8Cf or 2hand denoted as PCN.…”

“…All calculations were carried out at the DFT level with the B3LYP/6-31g(d) method in the Gaussian 03 program package. [35] HOMO and LUMO of PCN and models were constructed with Gview program on the basis of the results optimized with the B3LYP/6-31g(d) method.…”

Ultrathin Two‐Dimensional Semiconductors for Photocatalysis in Energy and Environment Applications

“…Since the Frank discovered that photocatalytic reaction can oxide CN − to OCN − , photocatalytic technology in the environmental‐protection application has received wide attention of researchers at home and abroad . Profiting from the unique advantages of ultrathin 2D semiconductors, such as a large space for light absorption and photocatalytic reaction and the ultrathin thickness facilitates the rapid transfer of photogenerated carriers to the surface or interface, the 2D semiconductors show great prospect for photodegradation organics . For example, Wang and co‐workers successfully synthesized freestanding monolayer Bi 2 WO 6 with a sandwich substructure of [BiO] + ‐[WO 4 ] 2 ‐[BiO] + by cetyltrimethylammonium bromide (CTAB) assistance (Figure ).…”

A Review on the Synergistic Features of Hexagonal Boron Nitride (White Graphene) as Adsorbent‐Photo Active Nanomaterial

“…Though the h BN has a structural resemblance to graphene it behaves as an electronic semiconductor with a wider band gap in the order of 5.5 to 6 eV due to the confined localization of the electrons. The confined localization makes it photo inactive . There by, necessitates the adaptation of novel strategies towards its bang gap reduction.…”