Surface modified and activated waste bone char for rapid and efficient VOCs adsorption

In this work, very efficient VOCs adsorbent was developed from waste bovine bone. After pyrolysis at 450 °C, the bone char was treated by H3PO4 for surface modification and activated by K2CO3 respectively. The prepared materials were characterized by N2 adsorption isotherms, SEM, FT-IR, and XPS. Adsorption/desorption and regeneration behavior of VOCs were also studied. Results showed that H3PO4 modification can effectively accelerate the adsorption process and after K2CO3 activation, a new hierarchical pore structure was found with an ultrahigh total pore volume of 2.807 cm3/g. The specific adsorption capacity for typical VOC reached ∼13.03 mmol/g which is much higher than literature data under the same condition. Static toluene adsorption test on the prepared activated bone-char revealed that the hierarchical structure has provided abundant adsorption sites and the adsorption behavior can be well described by the pseudo-second-order model. The dynamic/static adsorption ratio increased from 70.31% to 78.62% due to less mass transfer resistance by surface modification. [Display omitted] •Adsorbent with high pore volume and hierarchical pore structure has been prepared.•Adsorption process can be accelerated by surface modification.•Surface modification can reduce mass transfer resistance during dynamic adsorption.•A three-stages adsorption process of bone char has been investigated.