Removal of hydrogen sulfide in air using cellular concrete waste: Biotic and abiotic filtrations

Abstract

Please cite this article as: M. Ben Jaber, A. Couvert, A. Amrane, P.L. Cloirec, E. Dumont, Removal of hydrogen sulfide in air using cellular concrete waste: biotic and abiotic filtrations, Chemical Engineering Journal (2017), doi: http://dx.doi.org/10. 1016/j.cej.2017.03.014 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThe objective of this study was to investigate the removal of hydrogen sulfide (H 2 S) present in air using cellular concrete waste as the packing material. Air filtration was performed under biotic and abiotic conditions. Experiments were carried out in a laboratory-scale PVC column (internal diameter of 300 mm) filled with a volume of 70 L of cellular concrete (1 m height).The polluted air flow was generated at 4 m 3 h -1 corresponding to an Empty Bed Residence Time (EBRT) of 63 s. In dry conditions without biomass (abiotic conditions), cellular concrete can be an effective medium for the treatment of H 2 S in air. For an H 2 S concentration of 100 ppmv, the removal efficiency was around 70 % (Elimination Capacity (EC) of 5.6 g m -3 h -1 ). This finding can be explained by the physicochemical reactions that can take place between H 2 S and the cellular concrete components (mainly CaO, CaCO 3 and Fe 2 O 3 ).However, interactions between cellular concrete and H 2 S are not yet fully understood. Used as a packing material for H 2 S biofiltration (biotic conditions), cellular concrete waste efficiently 2 treated (Removal Efficiency = 100 %) high concentrations of H 2 S (up to 133 ppmv corresponding to an EC of up to 10.5 g m -3 h -1 ). Physicochemical and biological mechanisms explaining H 2 S removal seem to occur simultaneously in the biofilter. At an EBRT of 63 s, the maximal elimination capacity (EC max ) was 17.8 g m -3 h -1 . A packed bed of cellular concrete also presents a satisfactory mechanical behavior with low pressure drops.

H2S removal using cellular concrete waste as filtering material: Reactions identification and performance assessment

“…On average, H2S removal efficiency was 47% and 4% for filters BF3 and BF2, respectively, whereas 28% was obtained for the filter BF1 (mixture). Results obtained for cellular concrete waste alone were nonetheless lower than those reported in Ben Jaber et al [5], i.e. RE = 70% for an H2S concentration of 100 ppm at EBRT = 63 s. In terms of sulphur proportion (in % weight), analysis using X-ray…”

“…Cellular concrete may be used as adsorbent for heavy metals or halogens [6][7][8]. However, due to its specific surface area (44 m 2 g -1 ), adsorption tests carried out at laboratory scale indicated that cellular concrete waste used in this study is not a good adsorbent for H2S removal [5].…”

“…Properties of both materials are reported in Table 1. Analytical materials used to determine these properties are described by Ben Jaber et al [5]. Table 2 shows that both materials exhibit close chemical compositions determined by using an Energy Dispersive X-ray Fluorescence Spectrometer (EDX-800HS, Shimadzu Company).…”

“…The interest for biotechniques is increasing because of their high removal efficiency and low running cost [1]. Incidentally, recent study has highlighted that cellular concrete waste, which can be used as packing material for biofiltration [2][3][4], could also be an effective medium for the treatment of H2S in air without any microbial population [5] (i.e in abiotic conditions). For an H2S concentration of 100 ppmv, a removal efficiency around 70% was reported.…”

Microbial Ecology of Biofiltration Units Used for the Desulfurization of Biogas

“…Natural organic materials have normally been preferred for packing conventional biofilters (i.e., compost, peat, wood bark and soil among others) since they provide large specific areas with high porosity, low pressure loss, lightweight, low-cost, buffering and water-retaining capacity, intrinsic nutrient content as well as the presence of indigenous microbial consortia [51,52]. The drawbacks of conventional biofilters, especially under long-term operation, are (a) the accumulation of biomass and S 0 which may lead to bed clogging episodes (i.e., the reduction of inter-particle void space) causing preferential flow in the biofilter bed and pressure drop with the consequent reduction of the available mass transfer area; (b) acidification of the packing material due to the generation of SO 4 2− which leads to the formation of H 2 SO 4 , especially at the inlet area where the H 2 S concentration and oxidation rate are higher, which may decrease the pH to values <1 causing inhibition of the microbial activity and decrease in the mass transfer rate into the biofilm; (c) compaction and degradation of the packing material provoking a reduction of media porosity and buffering capacity [53][54][55][56][57].…”