Investigation On The Synthesis Of Porous Boron Nitride And Adsorption Characteristics For Congo Red And Rhodmine B

Porous boron nitride material is III-V nonmetallic compound and it has different scales of pores and high surface area. It has excellent optoelectronic properties, adsorption properties, permeability characteristics, so it has broad application prospects in many fields.The hexagonal boron nitride performs the great advantages in the field of adsorption.In this paper, high purity boric acid and melamine as boron and nitrogen sources, the precursor of boron nitride turned into porous boron nitride material at a high temperature.1-BN and 2-BN were synthesized at 1000 oC and 1550 oC. These samples were analyzed by SEM, TEM and BET to characterize the morphology and pore characteristics. The test results of XRD and FTIR to hexagonal boron nitride sample showed that these samples had highly crystalline phase and its surface hang a lot of functional groups. Then, the factors of absorption process which two kind of samples adsorbed Rhodamine B(RhB) and Congo red(CR) include concentration, initial pH, adsorption time and experiment temperature.Adsorption model: adsorption isotherms and kinetic models. The main conclusions:1. The factors of impacting adsorption value: maximum adsorption of 1-BN and 2-BN to RhB and CR increase following initial concentration. The maximum adsorption capacity of 1-BN to RhB: pH <7, the adsorption capacity decreases with increasing initial pH value;pH> 7, the adsorption capacity remained stable. The maximum adsorption capacity of1-BN to CR: adsorption remained almost unchanged in neutral and acidic conditions;pH>7, the adsorption capacity decreased with initial pH value increasing; The maximum adsorption capacity of 1-BN increased to CR and RhB with the experimental temperature rising significantly.2. Adsorption model: Adsorption isotherm models were fitted to the data so as to analyzed the absorption process of the adsorbents. The adsorption data fitted the Langmuir model satisfactorily with an R2. The maximum adsorption capacity of CR on 1-BN and2-BN were 82.57 mg/g and 71.50 mg/g. The maximum adsorption of RhB on 1-BN and2-BN were 216.2 mg/g and 201.24 mg/g. According to the results of D-R model,two adsorption of boron nitride fibers to RhB and CR is chemisorption. Comparing the results of Pseudo-first-order model and Pseudo-second-order model,the adsorption of dye onto1-BN and 2-BN does follow the Pseudo-second-order kinetics.