Developing a Novel Layered Boron Nitride–Carbon Nitride Composite with High Efficiency and Selectivity To Remove Protonated Dyes from Water

Abstract

A layered boron nitride (BN)−carbon nitride (CN) composite has been successfully synthesized by calcinating a mixture of BN nanoparticles and urea at 600 °C, wherein CN is formed from the thermal polymerization of urea during the calcination process. TEM analyses confirm that the BN-CN composite has a layered structure, being different from the morphologies of BN nanoparticles and CN. FTIR, XRD, and NMR results support that the layered BN-CN composite is most likely formed via the dehydration reaction between the -OH groups in the BN nanoparticles and the -NH 2 groups in CN during the calcination process, which links BN nanoparticles and CN together to form the layered composite. The layered BN-CN composite can, with high efficiency, remove Neutral Red (NR) and Malachite Green (MG) from water (NR removal quantity: 1350.1 mg/g, concentration: 220 mg/L; MG removal quantity: 1040.6 mg/g, concentration: 120 mg/L), whereas the layered BN-CN composite has low efficiency to remove Methyl Orange (MO), Methylene Blue (MB), and Crystal Violet (CV) from water. The quantities of MO, MB, and CV removed are all just around 60 mg/g with a concentration of 120 mg/L. NR and MG are both protonated dyes, and their positive charges are from the bound H + . The layered BN-CN composite has high affinity for H + , which can cause the pH of the deionized water to increase to 8.89 from the initial 6.82. This may be responsible for the high removal efficiency of the layered BN-CN composite for NR and MG. Furthermore, the layered BN-CN composite can selectively remove NR (or MG) from NR-MO and NR-MB solutions (or MG-MO and MG-MB solutions).

Adsorption Characteristics of Chitosan-Modified Bamboo Biochar in Cd(II) Contaminated Water

“…As shown in Figure 4(a), the adsorption rates of BB and CBB in Cd(II) contaminated water depend on the pH values and show similar trends. e adsorption rates of CBB increased from 66.78% to 90.66%, respectively, over the pH values range from 3 to 7, while the adsorption of Cd(II) tends to be stable when pH is greater than 7. erefore, the optimal pH of CBB on the Cd(II) removal efficiency is 7. is is consistent with the results reported for heavy metal removal from industrial wastewater using chitosan-modified oil palm shell charcoal which was in the pH values range of 6.8-7.1 [47]. erefore, our results demonstrated that pH is one of the most essential parameters in the Cd(II) adsorption process and might change the function groups, mainly oxygen-containing groups, of CBB [51].…”

“…Adsorption. pH, an important parameter for affecting heavy metals adsorption, could affect the surface potential, counter ions concentration on the functional groups, and ionization degree of adsorbents [47][48][49][50]. To examine the effect of pH on the Cd(II) adsorption, the pH values were varied from 3 to 8.…”

Synthesis of an Environmentally Friendly Boron Nitride/Dye Composite Photocatalytic Material and Study on Degradation Mechanism of Tetracycline Wastewater

“…Based on our previous work, boron nitride is synthesized by oxygen restriction method [26] . Typical diffraction peaks around 26.6 and 41.8° are shown in Figure 1(a).…”

Effective sorptive removal of five cationic dyes from aqueous solutions by using magnetic multi-walled carbon nanotubes

“…The adsorption of four dyes, MG, AO, CV and RhB, on MMWCNTs were tested over a wide pH range from 4.0 to 10.0. However, the adsorption process of NR was investigated in a relative narrow pH range from 4.0 to 7.0 as precipitates would be formed under alkaline conditions (Guo et al 2019). As illustrated in Figure 2, the adsorption amounts for MG (Figure 2 electrostatic attraction with cationic dyes under increased pH values, thus the adsorption amounts of dyes gradually increased.…”