Methods for synthesizing macroscale 3D heteroatom-doped carbon nanotube materials (such as boron doped carbon nanotube materials) and compositions thereof. Macroscopic quantities of three-dimensionally networked heteroatom-doped carbon nanotube materials are directly grown using an aerosol-assisted chemical vapor deposition method. The porous heteroatom-doped carbon nanotube material is created by doping of heteroatoms (such as boron) in the nanotube lattice during growth, which influences the creation of elbow joints and branching of nanotubes leading to the three dimensional super-structure. The super-hydrophobic heteroatom-doped carbon nanotube sponge is strongly oleophilic and an soak up large quantities of organic solvents and oil. The trapped oil can be burnt off and the heteroatom-doped carbon nanotube material can be used repeatedly as an oil removal scaffold. Optionally, the heteroatom-doped carbon nanotubes in the heteroatom-doped carbon nanotube materials can be welded to form one or more macroscale 3D carbon nanotubes.