Although tremendous works have been done on metal adsorption via biochar, mechanisms responsible for metal adsorption remain uncertain. This is the first work that provides direct evidence on the identification of Ni(II), Zn(II), and Cu(II) adsorption mechanisms on pineapple leaf biochar (PLB) using surface characteristics analyses, including X-ray photoelectron spectroscope (XPS), Fourier transform infrared spectroscope (FTIR), and scanning electron microscope with energy-dispersive X-ray spectroscope (SEM-EDS). From Langmuir isotherm fitting, the maximum adsorption capacity of PLB for Ni(II), Zn(II), and Cu(II) are 44.88, 46.00, and 53.14 mg g⁻¹, respectively, surpassing all biochars reported in the literature. Findings of surface characterization techniques coupled with cation released during adsorption, cation exchange, and surface complexation mechanisms were proposed. PLB is reusable and remains sufficient adsorption capacity even six consecutive cycles via pressure cooker regeneration. With high regenerability and ultrahigh adsorption capacity, PLB defines itself as a promising adsorbent for future applications in metal-laden wastewater.

尽管已经在通过生物炭吸附金属方面做了大量工作，但金属吸附的机制仍然不确定。这是第一项使用表面特征分析，包括 X 射线光电子能谱仪 (XPS) 鉴定菠萝叶生物炭 (PLB) 上 Ni(II)、Zn(II) 和 Cu(II) 吸附机制的直接证据。 )、傅里叶变换红外光谱仪 (FTIR) 和带有能量色散 X 射线光谱仪 (SEM-EDS) 的扫描电子显微镜。根据朗缪尔等温线拟合，PLB 对 Ni(II)、Zn(II) 和 Cu(II) 的最大吸附容量分别为 44.88、46.00 和 53.14 mg g ^-1，分别超过文献中报道的所有生物炭。提出了表面表征技术与吸附过程中释放的阳离子、阳离子交换和表面络合机制相结合的发现。PLB 是可重复使用的，通过压力锅再生，即使连续六个循环也能保持足够的吸附能力。凭借高再生性和超高吸附能力，PLB 将自己定义为未来在含金属废水中应用的有前途的吸附剂。