Anyone who has ever hesitated in front of a trash bin knows the problem: It’s hard to determine what can be recycled. Consider the average potato chip bag. It’s got film plastic, metal, dyes, and food residue; it’s complicated. Today’s recycling doesn’t handle complexity well, so the typical chip bag is destined for the landfill. Landfills take up space, of course, but there is a much more serious problem associated with them — one that was underscored for Daniel R. Cohn, currently an MIT Energy Initiative (MITEI) research scientist, when he…