MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
Environ Pollut. 2017 Dec;231(Pt 1):229-236. doi: 10.1016/j.envpol.2017.08.023. Epub 2017 Sep 25.
The effects of humic acid (HA) and heavy metals (Cu and Ag) on the sorption of polar and apolar organic pollutants onto biochars that were produced at temperatures of 200 °C (BC200) and 700 °C (BC700) were studied. Due to the plentiful polar functional groups on BC200, cationic propranolol exhibited higher levels of sorption than naphthalene on BC200 while naphthalene and propranolol showed similar sorption capacities on BC700. HA changed the characteristics of biochars and generally inhibited the sorption of target organic pollutants on biochars; however, enhancement occurred in some cases depending on the pollutants involved and their concentrations, biochars used and the addition sequences and concentrations of HA. On BC200, HA modifications mainly influenced sorption by decreasing its polarity and increasing its aromaticity, while on BC700, the surface area and pore volume greatly decreased due to the pore-blocking effects of HA. Residue dissolved HA in solution may also contribute to sorption inhibition. Complexation between polar functional groups on BC200 and heavy metals slightly enhanced the sorption of neutral naphthalene and significantly enhanced that of anionic 4-nitro-1-naphtol, while limited the sorption of cationic propranolol. Heavy metals together with their associated water molecules decreased the sorption of target chemicals on BC700 via pore-filling or pore-mouth-covering. Inhibition of heavy metals for 4-nitro-1-naphthol was found to be the weakest due to the bridge effects of heavy metals between 4-nitro-1-naphtol and BC700. The higher polarizability of Ag led to the increase of its sorption on biochars in the presence of organic aromatic pollutants. The results of the present study shed light on the sorption mechanisms of bi-solute systems and enable us to select suitable biochar sorbents when chemicals co-exist.
研究了腐殖酸（HA）和重金属（Cu 和 Ag）对在 200°C（BC200）和 700°C（BC700）温度下制备的生物炭上极性和非极性有机污染物吸附的影响。由于 BC200 上含有丰富的极性官能团，阳离子心得安对 BC200 的吸附水平高于萘，而萘和心得安对 BC700 的吸附能力相似。HA 改变了生物炭的特性，通常会抑制目标有机污染物在生物炭上的吸附；然而，在某些情况下，取决于涉及的污染物及其浓度、使用的生物炭以及 HA 的添加顺序和浓度，会出现增强的情况。在 BC200 上，HA 的修饰主要通过降低其极性和增加其芳香性来影响吸附，而在 BC700 上，由于 HA 的孔阻塞效应，表面积和孔体积大大减少。溶液中溶解的 HA 残留物也可能有助于吸附抑制。BC200 上的极性官能团与重金属之间的络合作用略微增强了中性萘的吸附，显著增强了阴离子 4-硝基-1-萘酚的吸附，同时限制了阳离子心得安的吸附。重金属及其相关水分子通过孔填充或孔口覆盖，降低了目标化学品在 BC700 上的吸附。由于重金属在 4-硝基-1-萘酚和 BC700 之间的桥接作用，发现重金属对 4-硝基-1-萘酚的抑制作用最弱。Ag 的较高极化率导致其在存在有机芳香污染物的情况下在生物炭上的吸附增加。本研究的结果阐明了双溶质体系的吸附机制，使我们能够在化学品共存时选择合适的生物炭吸附剂。
