Adsorptive Removal of Bisphenol A Using N-Doped Biochar Made of Ulva prolifera

Excess biomass of Ulva prolifera (U. prolifera) which is a marine macroalgae capable of forming green tides due to the marine eutrophication has become a huge burden for both environment and economic development in the coastal zone. U. prolifera samples were collected from a beach that was piled up with fresh U. prolifera biomass due to the outbreak of green tide. The N-doped carbon adsorbent (U. proliferabased biochar) with N content of 2.6% was prepared through a rapid hydrothermal carbonization process, and used for the adsorptive removal of bisphenol A (BPA) known as endocrine-disrupting chemicals (EDCs). The Brunauer-Emmet-Teller (BET) specific surface area of the biochar was 25.43 m(2) g(-1), which was beyond those of many algal biochars. Efficient adsorptive removal of BPA using U. prolifera based biochar was achieved. Most of BPAwas removed within 4 h. The adsorption kinetics of BPA on U. prolifera based biochar fitted second-order model. The experimental adsorption capacities slightly changed from 9.38 +/- 0.11 to 9.68 +/- 0.21 mg g(-1) when the pH increased from 4.0 to 10.0, indicating that the influence of wastewater pH on the adsorption of BPA by the algal biochar can be neglected in most cases. The Langmuir isotherm fitted well with the BPA adsorption data. High temperature could enhance BPA adsorption on the biochar. According to the Langmuir model, the adsorption capacity (Q(m)) of BPA increased from 33.30 to 84.19 mg g(-1) when the temperature increased from 25 to 45 degrees C. High ionic strength led to the increase in the adsorption of BPA. The adsorption capacity (Q(m)) almost doubled when the ionic strength increased from 0 to 500 mM. These findings indicate a promising way to treat the excess U. prolifera biomass in coastal zone and control phenolic EDCs pollution at low cost.