Environmental Evaluation of the Improvements for Industrial Scaling of Zeolite Membrane Manufacturing by Life Cycle Assessment

Industrial scaling of zeolite membrane manufacturing is the general aspiration of the progresses in zeolite membranes synthesis, but the evaluation of their environmental aspects has been disregarded. The objective of this study is to quantify the environmental impacts of zeolite membrane synthesis with respect to the recent advances in the synthesis of zeolite membranes: (i) seed layers that allow membranes of submicron thickness; (ii) gel-less secondary treatments that avoid the use of large amounts of expensive structure directing agents; and (iii) use of low-cost polymer supports instead of conventional ceramic supports. Impacts are evaluated via life cycle assessment, which is performed using GaBi 8.7 Pro software. The impacts due to conventional and nanosheet seed layers are comparable but contribute only a small portion to the total impacts. Although the gel-less secondary growth has up to 10-fold lesser impacts compared to that for solvent-based secondary growth, a Piranha-treated nanosheets method, which eliminates secondary growth, can reduce impacts by an order of magnitude. It has also been found, that the majority of impacts are provided by the support layer. Advancements in hollow fiber synthesis, especially using thinner fibers and less-aggressive solvents, can considerably reduce the impacts associated with overall membrane synthesis.