A highly effective arsenic catcher for removing raw water from shale gas-Cucurbit[7]uril modified magnetic biochar

Abstract

Shale gas is a low-carbon, clean, and high-reserve natural gas resource, but the development process requires a large amount of fresh water and chemicals, which can lead to a large amount of As3+ in the shale gas raw water. The removal of As³⁺ from shale gas raw water is necessary because of the serious hazards that As³⁺ can cause once it enters the human body. In this study, a loofah biocarbon material (CBMM) co-modified by Cucurbit[7]uril (CB[7]) and Fe₃O₄ was prepared. The successful synthesis of the materials was verified by various characterization methods. The material possesses excellent magnetic separation properties and can achieve rapid recovery within 50 s. The adsorption process is spontaneous and endothermic, and the experimental data have excellent correlation with pseudo-first-order kinetic (R² > 0.99) and Langmuir model (R² > 0.99). The maximum adsorption capacity of CBMM was 76.43 mg/g at 20 °C. In addition, CBMM still possessed 74.8 % of the initial adsorption capacity after 7 cycles of the experiment. CBMM also had excellent As³⁺ removal efficiency (90.1 %) in the study of actual shale gas raw water. In conclusion, CBMM is a very promising adsorbent for the removal of As³⁺ from shale gas raw water.