A system and process for gasification of a carbonaceous feedstock uses pyrolysis to produce a gas product, which may include methane, ethane, and other desirable hydrocarbon gases, and a solids product, which includes activated carbon or carbon. The gas product may then be filtered using at least a portion of the activated carbon from the solids product as a filtering medium. In an embodiment, at least some of the noxious chemicals are sequestered or removed from the gas product in one or more filtering steps using the activated carbon as a filtering medium. In a further embodiment, the filtering steps are performed in stages using activated carbon at different temperatures. A high-temperature pyrolysis system that produces activated carbon may be combined with another high-temperature pyrolysis system that does not produce activated carbon to provide filtering of noxious compounds using activated carbon from the first high-temperature pyrolysis system. A high-temperature pyrolysis system may be combined with one or more low-temperature feedstock conversion processes such that waste heat from the high-temperature pyrolysis system is used to operate the low-temperature process. A novel non-wetting carbon having pores fused with silica can be produced from using the system and process.