Two commercial activated carbons, namely STIX and AP4, were selected to investigate their ability for siloxane adsorption and further thermal regeneration in relation with their different physico-chemical properties. In the frame of biogas purification, the studied siloxanes were L2, L3, L4 (linear molecules) and D4, D5 (cyclic molecules). The maximum capacity of adsorption was estimated by gas chromatography and gravimetric methods. AP4 presents better adsorptive properties comparing with STIX irrespective of the type of siloxane. Thermal regeneration after siloxanes adsorption was followed up to 400 °C by both gas chromatography and in situ DRIFTS. Except L2, the siloxane polymerization proceeds on the AC containing alkali metals (K, Na) as revealed by the observed release of their decomposition products during the thermodesorption treatment. The same sites are responsible for the cleavage of SiO bonds in linear molecules and formation of L2 as primary product above 100 °C. The presence of such sites, possibly strong basic sites, is detrimental to the regenerability of the spent adsorbent and to the adsorption which could be limited by partial blockage of the AC porosity. Interestingly the regenerability of the alkali-free AC depends only on the volatility of the siloxane.

选择了两种市售活性炭，即STIX和AP4，以研究其与不同理化性质相关的硅氧烷吸附和进一步热再生的能力。在沼气净化的框架中，研究的硅氧烷为L2，L3，L4（线性分子）和D4，D5（环状分子）。通过气相色谱法和重量法估算最大吸附容量。与STIX相比，AP4表现出更好的吸附性能，而与硅氧烷的类型无关。通过气相色谱法和原位DRIFTS追踪硅氧烷吸附后的热再生温度，最高可达400°C。除L2外，硅氧烷聚合反应在含AC的碱金属（K，Na）上进行，这是由于在热脱附处理过程中观察到其分解产物的释放所表明的。高于100°C时，线性分子中的O键结合并形成L2作为主要产物。此类位点（可能是强碱性位点）的存在不利于用过的吸附剂的再生能力，并可能受到部分AC孔隙阻塞的限制。有趣的是，无碱AC的可再生性仅取决于硅氧烷的挥发性。