NiSe ultralong nanobelts were synthesized by a solvothermal reaction of Ni with Se and KBH4 in ethylenediamine and subsequent annealing in Ar. The aspect ratios of NiSe ultralong nanobelts can be tuned by altering the reaction time. The adsorption performance of NiSe nanostructures with different aspect ratios was investigated, and the as-obtained NiSe ultralong nanobelts exhibited excellent adsorption capability of malachite green in wastewater, which could be attributed to their unique honeycomb-like assembly and high surface area. The adsorption process agreed well with the pseudo-second-order kinetics and the Langmuir isotherm equation. Thermodynamic parameters indicated that the adsorbent processes were spontaneous. Electrostatic attraction between malachite green and NiSe ultralong nanobelts was considered as the adsorption mechanism. The NiSe ultralong nanobelts could be regarded as a promising adsorbent for the removal of MG in wastewaters.
