الفهرس 
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Abstract
In this study, more attentions have been directed to utilize
solid/liquid waste byproducts as zero-cost starting precursors for
synthesize effective sorbent materials for petroleum wastewater
treatment. IN this regard, both pulping black liquor and palm-date
pits industrial wastes were treated via chemical and thermal
processes to generate three series of carbon-based materials:
granule activated carbon (gAC), 3D cross-linked Kraft lignin
biopolymer (KL), and hybrid biocomposites (gAC/KLx, x= 33, 50
and 67%). The prepared materials were fully characterized to
understand their crystalline nature, surface morphologies,
functionalities, surface area, porosity, surface charges, and
thermal and aqueous stabilities. The potential applicability of
these materials towards the removal of mono-aromatics pollutants
mixture (such as benzene, toluene, and xylene: termed as BTX)
was investigated in batch adsorption process. The effect of
adsorption parameters, including pH (3 -9), ionic strength (0 -100
g/L NaCl), adsorbent dose (5 -25 g/L), BTX concentrations (750
– 2250 mg/L), contact time (10 min – 24 h), and temperature (293
– 323 K), on the adsorption performance were investigated and
optimized. Moreover, the adsorption modeling via kinetic,
isotherm, and thermodynamic analysis were studied to
understanding the mechanism of BTX sorption onto the prepared gAC, KL, and gAC/KLx hybrids sorbents during oilfield
wastewater treatment. The studied adsorption processes were
evaluated using high performance liquid chromatography
(HPLC). Results indicated that the adsorption equilibrium of the
BTX pollutants onto the prepared adsorbent was achieved after 12
contacted time. It was found that the prepared adsorbents have
higher capability to achieve the highest BTX capacity at broad
ranges of ionic strength (0-100 g/L NaCl), pH (3 - 9), temperature
(293 -323K). The adsorption performance of BTX onto gAC and
gAC/KL was enhanced by increasing ionic strength to 100 g/L
due to salting out effect, which increase BTX hydrophobicity and
reduce ionic surface charge to promote mass diffusion
mechanism. However, it should be noted that the KL performance
at higher ionic strength decreased due to the instability of
biopolymer. Both gAC and hybrid gAC/KL at 50% blend ratio
exhibited the highest effectiveness for BTX removal (~100% of
750 mg/L BTX) over 5 reuse cycles, with higher selectivity in the
order of xylene > toluene> benzene. Comparatively, KL
biopolymer exhibited poor adsorption performance (52.6±3.4%
removal) and low stability over 5 reuse cycles with good
selectivity for benzene over toluene and xylene. Non-linear
modeling of adsorption kinetic (nine models) and isotherm (five
models) reflected the best fit of experimental adsorption data to
mixed-order kinetic (MOE) and Langmuir-Freundlich (L-FM) isotherm models. Such models fit to experimental adsorption data
indicated the existence of complex phenomena during adsorption
of BTX molecules onto the prepared adsorbent surfaces. Based on
kinetic and isotherm constants, the adsorption mechanism
suggested to best described by physico-sorption (activation
energy E ≈ 0.12 – 1.38 KJ/mol) via the hydrophobic interaction
and diffusion mechanisms. In respect to adsorption affinities, the
sorption of BTX molecules onto gAC and gAC/KL0.5 followed
the descending sequence of X (0.96 – 0.164 L/mg) > T (0.041 -
0.078 L/mg) > B (0.022 -0.009 L/mg). The maximum theoretical
BTX capacity using the best fitted Langmuir-Freundlich model
(L-FM) for gAC/KL0.5 was found to be higher than obtained by
gAC (363.9 and 360.1 mg/g, respectively), with higher initial
sorption (h) rate (≈742.47 mg/g.h) than of gAC (≈559.85 mg/g.h)
and KL (≈22.22 mg/g.h). Particularly, thermodynamic analysis
indicated favorable adsorption process of BTX onto gAC and
gAC/KL0.5 than pure KL sorbent. The sorption process is
physisorption (ΔH value < 80 kJ/mol), spontaneous, and
endothermic in nature when using gAC and gAC/KL0.5
compared to non-spontaneity in nature onto KL biopolymer.
Adsorption of BTX onto all the prepared adsorbents is mainly
dependent on the nature of adsorbent surface, adsorbate type, and
BTX concentration. For applied study, batch adsorption process
for real-petroleum wastewater sample collected from one of the oil & gas company in Egypt was investigated. the application
results verified the superior performance of gAC and gAC/KL0.5
adsorbents for complete removal of BTX and ethylbenzene
pollutants (> 98.5±0.76%)along with other polar organics such as
methanol (by ≈ 53.4 – 42.0%), mono-ethylene glycol (MEG =
64.3 – 47.8%), and diethylene glycol (DEG= 70.3 – 43.5%).
Economic cost analysis reflected that the production cost of
gAC/KL0.5 adsorbent (2.81±0.55 US $/kg) is low than of gAC
(∼3.73±0.32 US $/kg), and both are lower in cost than
commercially activated carbon in market place. At this end, it is
suggested that gAC/KL0.5 could be used as potential eco-friendly,
low-cost, and effective sorbent for treatment of petroleum
wastewater before disposal for save our natural ecosystem up to
five reuse cycles.
Keywords
Waste management, Activated carbon, Kraft lignin-based
biocomposite, BTX adsorption, Non-linear kinetic and isotherm
modeling, Petroleum wastewater treatment.