The main objective of a series of our researches is to develop a novel acoustic-based method for activation of biochar. This study investigates the capability of biochar in adsorbing Ni(II) as a hazardous contaminant and aims at enhancing its adsorption capacity by the addition of extra nitrogen and most probably phosphorous and oxygen containing sites using an ultrasono-chemical modification mechanism. To reach this objective, biochar physically modified by low-frequency ultrasound waves (USB) was chemically treated by phosphoric acid (H₃PO₄) and then functionalized by urea (CO(NH₂)₂). Cavitation induced by ultrasound waves exfoliates and breaks apart the regular shape of graphitic oxide layers of biochar, cleans smooth surfaces, and increases the porosity and permeability of biochar’s carbonaceous structure. These phenomena synergistically combined with urea functionalization to attach the amine groups onto the biochar surface and remarkably increased the adsorption of Ni(II). It was found that the modified biochar could remove > 99% of 100 mg Ni(II)/L in only six hours, while the raw biochar removed only 73.5% of Ni(II) in twelve hours. It should be noted that physical treatment of biochar with ultrasound energy, which can be applied at room temperature for a very short duration, followed by chemical functionalization is an economical and efficient method of biochar modification compared with traditional methods, which are usually applied in a very severe temperature (>873 K) for a long duration. Such modified biochars can help protect human health from metal-ion corrosion of degrading piping in cities with aging infrastructure.

我们一系列研究的主要目的是开发一种基于声学的生物炭活化方法。这项研究调查了生物炭吸附Ni（II）作为有害污染物的能力，并旨在通过超声化学修饰机制通过添加额外的氮以及最可能的含磷和含氧位点来提高其吸附能力。为了实现这一目标，对经过低频超声波（USB）物理修饰的生物炭进行了磷酸（H ₃ PO ₄）化学处理，然后通过尿素（CO（NH ₂）₂）。超声波引起的空化使生物炭的石墨氧化物层的规则形状剥落并破裂，清洁光滑的表面，并增加生物炭的碳质结构的孔隙率和渗透性。这些现象与尿素官能化协同结合以将胺基连接到生物炭表面上，并显着增加了Ni（II）的吸附。发现改性的生物炭仅在六小时内就可以去除> 99％的100 mg Ni（II）/ L，而原始生物炭在十二小时内只能去除73.5％的Ni（II）。应当指出的是，与传统方法相比，利用超声波能量对生物炭进行物理处理可以在室温下进行很短的时间，然后进行化学功能化，是一种经济有效的生物炭改性方法，通常在非常苛刻的温度（> 873 K）下长时间使用。在基础设施老化的城市中，这种经过改良的生物炭可帮助保护人类健康免受金属离子腐蚀，因为金属离子不会腐蚀管道。