Determination of mercury distribution inside spent compact fluorescent lamps by atomic absorption spectrometry

Abstract

a b s t r a c tIn this study, spent compact fluorescent lamps were characterized to determine the distribution of mercury. The procedure used in this research allowed mercury to be extracted in the vapor phase, from the phosphor powder, and the glass matrix. Mercury concentration in the three phases was determined by the method known as cold vapor atomic absorption spectrometry. Median values obtained in the study showed that a compact fluorescent lamp contained 24.52 ± 0.4 ppb of mercury in the vapor phase, 204.16 ± 8.9 ppb of mercury in the phosphor powder, and 18.74 ± 0.5 ppb of mercury in the glass matrix. There are differences in mercury concentration between the lamps since the year of manufacture or the hours of operation affect both mercury content and its distribution. The 85.76% of the mercury introduced into a compact fluorescent lamp becomes a component of the phosphor powder, while more than 13.66% is diffused through the glass matrix. By washing and eliminating all phosphor powder attached to the glass surface it is possible to classified the glass as a non-hazardous waste.

Removal of mercury bonded in residual glass from spent fluorescent lamps

“…Furthermore, the influence of the L/S ratio is less significant at low pH values, since the divalent mercury is more soluble in an acid solution than in ultrapure water (Rey-Raap and Gallardo, 2012). In fact, when ultrapure water was used as an extraction solution, the difference between the results obtained for an L/S ratio of 10 and a ratio of 2 was 61.11%.…”

“…During lamp usage, metallic mercury reacts with the phosphor powder to form more soluble compounds of mercury (Lee et al, 2009). In fact, when a lamp becomes waste, most of the mercury is in its divalent state (Dunmire et al, 2003) and, furthermore, its components (especially the phosphor powder (Rey-Raap and Gallardo, 2012)) are contaminated by mercury (Durão et al, 2008) In view of this situation, the European Commission, under Directive 2002/95/EC on waste electrical and electronic equipment (WEEE), states as one of its objectives the reduction of hazardous components in WEEE, in which fluorescent lamps are included (in the case of compact fluorescent lamps (CFLs), the concentration of mercury should not exceed 5 mg per lamp), in order to improve the effectiveness of environmental protection. According to this directive, Member States shall ensure that producers recover a minimum of 70% by average weight per appliance.…”

Processes and Technologies for the Recycling of Spent Fluorescent Lamps

“…Part of mercury introduced into a lamp is used to produce visible light and the other part of this metal interacts with the phosphor powder and the glass matrix 4 . The typical lamp consists of a glass tube fi lled with an inert gas (argon, neon, krypton and/or xenon) at low pressure (3 mbar) and mercury vapor at low partial pressure.…”

“…In case of compact fl uorescent lamps (CFLs) concentration of mercury should not exceed 5 mg per lamp. The management of spent CFLs is regulated by Directive 2002/96/EC on electrical and electronic equipment, and waste management (WEEE) [3,4]. The spent fl uorescent lamps can be treated by means of mechanical, thermal and chemical processes.…”

DESIGN AND EVALUATION OF A Hg(II) SENSOR BASED ON THE RESPONSE OF A POLY(3,4-ETHYLENEDIOXYTHIOPHENE) MODIFIED ELECTRODE

“…atomic absorption spectrometry 31,32 , spectrofluorimetry 33,34 , atomic fluorescence spectrometry 35 , among others 36 , and since most of them are not only very time consuming but require costly and sophisticated instrumentation and/or expensive pre-treatment, the technique proposed in this work is quite simple and cheap. Consequently, the development of an approach that allows fast and in-situ determination of this pollutant is necessary.…”