Adsorption of volatile polar organic solvents on water hyacinth (Eichhornia crassipes) root biomass: thermodynamic parameters and mechanism

Abstract

The adsorbent properties of dried water hyacinth root biomass towards four polar solvents (dichloromethane, ethyl acetate, diethyl ether and acetone) were studied by inverse gas chromatography between 40 and 70°C. The enthalpy of adsorption values obtained for the adsorption of the four solvents on untreated root biomass range from -51.234 kJ mol -1 for acetone, an amphoteric solvent, to -74.658 kJ mol -1 for dichloromethane, an acidic solvent. Mineral acid and organic solvent treatment led to reduction in the values of the enthalpy of adsorption for all four solvents. The Lewis acidity parameters calculated from the enthalpy of adsorption values were 0.408, 0.267 and 0.356, while the corresponding Lewis basicity parameters were 3.76, 1.80 and 2.34, respectively, for untreated, mineral acid-treated and organic solvent-treated water hyacinth root biomass. The Lewis basicity parameter-to-Lewis acidity parameter ratios for the untreated, acid-treated and organic solvent-treated biomass were found to be 9.22, 6.74 and 6.57, respectively, indicating (a) that all the surfaces of the untreated, mineral acid-treated and organic solvent-treated water hyacinth root biomass are basic in nature and (b) that for all volatile polar solvents studied, the adsorption interaction involves the lowest unoccupied molecular orbital of the solvent as the electron acceptor and the highest occupied molecular orbital of the water hyacinth root biomass surface adsorbent site as the electron donor.

Studying Mechanical, Thermal and Absorption, Characteristics of Water Hyacinth (Eichhornia Crassipes) Plant Fibre Reinforced Polymer Composites

“…According to the results obtained, the strength of the fibre composite increased significantly with increasing the fibre length up to 20 mm, but decreased when the fibre length was increased further (25 mm), possibly due to the agglomeration effect from the primary fibre reinforcements. The results of the mechanical strength test (tensile, flexural, and impact) can be interpreted as showing that the fibre length of 20 mm reinforced with 30 wt.% fibres achieved a higher mechanical strength content than the remaining fibre lengths (Promdee et al 2012;and Muchanyereyi et al 2016).…”

Adsorptive Removal of Dichloromethane Vapor on FAU and MFI Zeolites: Si/Al Ratio Effect and Mechanism

“…Among the available removal technologies for chlorinated VOCs such as DCM that are emitted into air, adsorption is a well-established and effective technique for their removal and recovery from exhaust. − Activated carbon adsorption is widely used in industry due to ease of operation, low operating cost, and efficient recovery for most chlorinated VOCs. ,,,,− However, it has been recognized that activated carbon frequently encounters problems such as combustion, pore blocking, and hygroscopicity. As a result, alternative adsorbents have drawn more and more interest.…”