Kinetics and Thermodynamics of Adsorption for Aromatic Hydrocarbon Model Systems via a Coagulation Process with a Ferric Sulfate–Lime Softening System

Abstract

The adsorption mechanisms for model hydrocarbons, 4-nitrophenol (PNP), and naphthalene were studied in a coagulation-based process using a ferric sulfate–lime softening system. Kinetic and thermodynamic adsorption parameters for this system were obtained under variable ionic strength and temperature. An in situ method was used to investigate kinetic adsorption profiles for PNP and naphthalene, where a pseudo-first order kinetic model adequately described the process. Thermodynamic parameters for the coagulation of PNP and naphthalene reveal an endothermic and spontaneous process. River water was compared against lab water samples at optimized conditions, where the results reveal that ions in the river water decrease the removal efficiency (RE; %) for PNP (RE = 28 to 20.3%) and naphthalene (RE = 89.0 to 80.2%). An aluminum sulfate (alum) coagulant was compared against the ferric system. The removal of PNP with alum decreased from RE = 20.5% in lab water and to RE = 16.8% in river water. Naphthalene removal decreased from RE = 89.0% with ferric sulfate to RE = 83.2% with alum in lab water and from RE = 80.2% for the ferric system to RE = 75.1% for alum in river water. Optical microscopy and dynamic light scattering of isolated flocs corroborated the role of ions in river water, according to variable RE and floc size distribution.

A pyridinium-modified chitosan-based adsorbent for arsenic removal via a coagulation-like methodology

“…The better fit for the PFO kinetic model mirrors the trends observed for the removal of other pollutants during the CF process, unlike classical adsorption processes, as outlined elsewhere. 18,46,61 This further highlights the applicability of the prepared material for arsenic removal through this one-pot process, as compared to (batch) adsorption removal.…”

“…1), as described by Venegas-García & Wilson. 46 Briefly, a 600 mL beaker containing 400 mL of 5 mg per L arsenic solution (pH 7.5) was mixed by magnetic stirring. A filter paper (Whatman no.…”

“…The relatively low R 2 value (<0.95) obtained herein may be the result of employing a water insoluble adsorbent in a one-pot coagulation experiment, as described by Venegas-García & Wilson. 46 The approach illustrated in Fig. 1 is compared to a conventional kinetic setup with constant stirring that employs a lter barrier, as described by Mohamed et al 60 The adsorption process of arsenic occurs into two stages: a fast initial adsorption process, where ca.…”

Enhanced oral delivery of hesperidin-loaded sulfobutylether-β-cyclodextrin/chitosan nanoparticles for augmenting its hypoglycemic activity: in vitro-in vivo assessment study

“…In our study, the prepared Hsd/Cd/CS NPs displayed a narrow size distribution (PDI values less than 0.5) for F1, F2, F3, and F4 except for F5 (0.582 ± 0.16). It is well known that PDI values less than 0.5 indicate the homogenous nature of the NPs dispersion with narrow size distribution [ 100 – 103 ].…”