Biochar is emerging as a cost-effective, environmentally-sustainable adsorbent for removing organic contaminants (OC) from wastewater, stormwater, and drinking water, but strategies for managing exhausted biochar are needed. Here, pine biochar generated at 850 °C was exhausted by background dissolved organic matter isolated from surface water [dissolved organic carbon ∼4.2 mg L⁻¹, UV-absorbance at 254 nm (UVA₂₅₄) ∼0.10 cm⁻¹] and sulfamethoxazole (SMX) [∼200 ng L⁻¹], in a column. Exhausted biochar underwent a semi-oxic-thermal-regeneration step at 600 °C (i.e., heat treatment). SMX and UVA₂₅₄ adsorption capacity and breakthrough were evaluated in rapid small-scale column tests (RSSCTs). Relative to fresh biochar, heat treated biochar that had been exhausted exhibited ∼3.5-fold and ∼3-fold greater SMX and UVA₂₅₄ adsorption capacities, respectively, and ∼3-fold increase in adsorption efficiency (i.e., mass loss-adjusted SMX adsorption capacity). When applying the heat treatment to fresh biochar, a similar improvement in adsorption capacity was observed. Adsorption capacity and BET surface area were positively correlated and continued to increase after a second exhaustion–regeneration cycle, but the adsorption efficiency remained the same due to mass loss. SMX breakthrough correlated with that of UVA₂₅₄, which provides the basis for a rapid, inexpensive method to predict OC breakthrough. Heat-treated biochar's SMX adsorption capacity was ∼20% of activated carbon's. Greater empty-bed-contact times increased the SMX adsorption capacity of heat-treated biochar. These results suggest that thermal regeneration could enhance the economic and environmental sustainability of biochar sorbents.

中文翻译：

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生物炭热再生对磺胺甲恶唑和溶解性有机物吸附的影响

生物炭正在成为一种具有成本效益，对环境可持续的吸附剂，可从废水，雨水和饮用水中去除有机污染物（OC），但是需要管理用尽的生物炭的策略。在这里，在850℃下产生的松生物炭通过从表面水隔离背景溶解有机物[溶解的有机碳~4.2毫克的L用尽^-1，UV吸光度在254nm（UVA ₂₅₄）~0.10厘米^-1 ]和磺胺甲恶唑（ SMX）[〜200 ng L ^-1 ]，在列中。耗尽的生物炭在600°C下进行半有氧热再生（即热处理）。SMX和UVA ₂₅₄在快速小型色谱柱试验（RSSCT）中评估了吸附能力和突破。相对于新鲜生物炭，已用尽的热处理过的生物炭分别显示出约3.5倍和约3倍的SMX和UVA ₂₅₄吸附能力，并增加了约3倍的吸附效率（即，质量损失调整后的SMX吸附）容量）。当将热处理应用于新鲜生物炭时，观察到吸附能力的类似提高。吸附能力和BET表面积呈正相关，并在第二次疲劳-再生循环后继续增加，但由于质量损失，吸附效率保持不变。SMX突破与UVA _254的突破，这为预测OC突破的快速，廉价方法提供了基础。热处理过的生物炭的SMX吸附量约为活性炭的20％。更长的空床接触时间增加了热处理生物炭的SMX吸附能力。这些结果表明，热再生可以增强生物炭吸附剂的经济和环境可持续性。