预碳化是生物质活化生产活性炭（AC）时常用的一种预处理，它不仅影响活性炭的性质，而且影响生物质活化过程中生物油和气体的组成。在这项研究中，直接或通过预碳化对锯末/纤维素/木质素进行活化，特别关注预碳化对各种产品和环境演变的影响。结果表明，预碳化去除了大部分脂肪族结构，为所得生物炭形成孔隙造成了困难。然而，这以K 2 C 2 O 4、CO 2或H 2 O作为活化剂的生物油为代价提高了AC和气体的总产率。AC的高产率和高比表面积不能同时获得，在应用中需要平衡。相反，ZnCl 2或H 3 PO 4作为活化剂通过直接活化生物质产生更多具有发达孔隙结构的AC，因为它们催化生物质中脂肪族结构的脱水，但不催化生物炭中脂肪族结构的脱水。生命周期评估（LCA）表明，预碳化比直接活化对环境和能源消耗的影响更大。ZnCl 2和CO 2对化石燃料枯竭和全球变暖的影响最小。直接活化在生产活性炭时表现出较低的环境影响，且具有更发达的孔隙结构，使其成为更理想的活性炭生产途径。

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Pre-carbonization is one frequently used pre-treatment for production of activated carbon (AC) from activation of biomass, which impacts not only nature of AC but also composition of bio-oil and gases in activation of biomass. In this study, activation of sawdust/cellulose/lignin directly or via pre-carbonization were conducted, with a particular focus on effects of pre-carbonization on evolution of the various products and environment. The results indicated that the pre-carbonization removed significant portion of aliphatic structures, creating difficulty for developing pores from the resulting biochar. This, however, enhanced overall yields of AC and gases at expense of bio-oil with K2C2O4, CO2 or H2O as activators. The high yield and high specific surface area of AC could not be obtained simultaneously and needs to be balanced in application. In converse, ZnCl2 or H3PO4 as activators generated more AC with developed pore structures via direct activation of biomass, as they catalyzed the dehydration of aliphatic structures in biomass, but not in biochar. The life cycle assessment (LCA) indicated that the pre-carbonization led to a higher impact to environment and energy consumption than the direct activation. ZnCl2 and CO2 showed the smallest influence on the fossil fuel depletion and global warming. Direct activation exhibited lower environmental impact in the production of AC with more developed pore structures, rendering it a more desirable route for production of AC.