A dust separator in which a plurality of elongated emission electrodes are detachably held at one end in respective holder fittings secured to a pair of parallel, slightly-resilient inner frame members, or holders, which in turn are secured to substantially non-resilient outer frame members, and at their other ends in at least one holder fitting secured to a common cylindrical central holder extending between and parallel to the frame members; the electrode assembly is tensioned by adjustment of screws fastening said inner frame members or holders to said outer frame members. In one form the holder fittings are hollow cylinders through which the electrodes extend, and the electrodes are positioned in the fittings by their bent-over ends and clamped therein by tubular members forced into the hollow cylinders. In another form, specially-shaped holder shoes are used, in which dove-tailed ends of the electrodes are held. In both forms, the emission electrode preferably is folded slightly about its longitudinal axis to produce a V-shaped cross section which provides strength, good electrical contact and ease of assembly.