U.S. patent application number 16/733452 was filed with the patent office on 2020-09-24 for synthesis of hydrochar from jackfruit.
The applicant listed for this patent is KING SAUD UNIVERSITY. Invention is credited to Zeid Abdullah ALOTHMAN, Ayoub Abdullah ALQADAMI, Moonis Ali KHAN, Masoom Raza SIDDIQUI.
Application Number | 20200299598 16/733452 |
Document ID | / |
Family ID | 1000004565082 |
Filed Date | 2020-09-24 |
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United States Patent
Application |
20200299598 |
Kind Code |
A1 |
KHAN; Moonis Ali ; et
al. |
September 24, 2020 |
SYNTHESIS OF HYDROCHAR FROM JACKFRUIT
Abstract
A method of producing hydrochar from jackfruit peel biomass
includes hydrothermal carbonization of jackfruit peel biomass by
autoclaving at 150.degree. C.-250.degree. C. for about 3 hours to
produce a hydrochar. The hydrochar can be activated by treatment
with phosphoric acid (H.sub.3PO.sub.4), hydrogen peroxide
(H.sub.2O.sub.2), or a combination thereof. The hydrochar produced
according to the method is particularly effective at removing
azo-dyes, and specifically methylene blue, from aqueous solutions
such as industrial waste water.
Inventors: |
KHAN; Moonis Ali; (Riyadh,
SA) ; ALQADAMI; Ayoub Abdullah; (Riyadh, SA) ;
SIDDIQUI; Masoom Raza; (Riyadh, SA) ; ALOTHMAN; Zeid
Abdullah; (Riyadh, SA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KING SAUD UNIVERSITY |
Riyadh |
|
SA |
|
|
Family ID: |
1000004565082 |
Appl. No.: |
16/733452 |
Filed: |
January 3, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16360397 |
Mar 21, 2019 |
10557098 |
|
|
16733452 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10L 5/447 20130101;
C01B 32/20 20170801; C01B 32/324 20170801 |
International
Class: |
C10L 5/44 20060101
C10L005/44; C01B 32/324 20060101 C01B032/324; C01B 32/20 20060101
C01B032/20 |
Claims
1-17. (canceled)
18. A hydrochar of jackfruit peel, wherein the hydrochar of
jackfruit peel is produced by steps comprising: adding a jackfruit
peel biomass to a liquid carrier; subjecting the jackfruit peel
biomass in the liquid carrier to hydrothermal carbonization to
provide a hydrochar, the hydrothermal carbonization comprising
heating the jackfruit peel biomass in the liquid carrier to a
temperature ranging from 150.degree. C. to 250.degree. C. for a
period of time of 3 hours to provide the hydrochar; and separating
the hydrochar from the liquid carrier.
19. A hydrochar of jackfruit peel, wherein the hydrochar of
jackfruit peel is produced by steps comprising: drying jackfruit
peel and pulverizing the dried jackfruit peel to provide a
jackfruit peel biomass; adding the jackfruit peel biomass to water
to form a slurry; heating the slurry to a temperature ranging from
150.degree. C.-250.degree. C. for 3 hours in an autoclave to
provide a hydrochar; separating an initial hydrochar from the
liquid carrier; drying the initial hydrochar; and adding the dried
hydrochar to a solution comprising at least one of phosphoric acid
(H.sub.3PO.sub.4) and hydrogen peroxide (H.sub.2O.sub.2) to form an
activated hydrochar.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a division of U.S. application Ser. No.
16/360,397, filed Mar. 21, 2019, pending.
BACKGROUND
1. Field
[0002] The disclosure of the present patent application relates to
hydrochar (HC), and particularly to a jack fruit peel hydrochar
(JFHC) for the adsorptive removal of methylene blue (MB), a
cationic synthetic dye, from an aqueous environment.
2. Description of the Related Art
[0003] Dyes are used as coloring agents and may be classified on
the basis of their chromophores. Both synthetic and natural dyes,
together including more than 10,000 commercial dyes, are used in
various fields, including food science, arts, textiles, and
fashion.
[0004] Methylene blue (MB) is an azo dye, extensively used for
dyeing and printing applications across technological fields. In
low concentrations, MB is non-hazardous; however, acute MB exposure
can cause cyanosis, jaundice, Heinz body formation, vomiting, and
tissue necrosis in humans. Monitoring and limiting MB concentration
in wastewater streams before discharging them to water reservoirs
is essential in preventing such noxious effects.
[0005] Generally, used-dye contaminated wastewater treatment
technologies include processes based on advanced oxidation,
biodegradation, ion-exchange, and adsorption. Water treatment
technologies based on adsorption have advantages of operational
simplicity, economic feasibility and high efficiency. Activated
carbon (AC) is a conventional adsorbent used for sequestering
pollutants from water. However, regeneration and slow desorption
kinetics restrict wide range usage of AC. Additionally, AC is
commonly derived from non-renewable coal, and is therefore in
finite supply.
[0006] Char produced from an abundantly available solid waste
biomass--for example, from plants, animals and humans--is an
alternate material for incorporating into an adsorption-based waste
management approach. Char, whether biochar (BC) or hydrochar (HC),
produced from otherwise useless solid waste biomass, is a
carbonaceous product having a wide range of energy and
environmental applications. HC is typically generated by
hydrothermal carbonization (HTC) of wet/dry waste biomass in a low
temperature range of 150.degree. C.-350.degree. C. Relative to BC,
HC has high oxygen functional groups content, but lower porosity
and surface area.
[0007] Jackfruit (JF), Artocarpus heterophyllus, is widely grown in
tropical climates. Usually, a mature JF weighs 10 kg-25 kg. A
fibrous rind and unfertilized floral parts, comprising around 50%
of the JF mass, contribute no economic or nutritional value and are
usually discarded as waste. The jack fruit peel (JFP) thereby
presents a significant source of wasted biomass.
[0008] Accordingly, a method of synthesizing hydrochar from
jackfruit solving the aforementioned problems is desired.
SUMMARY
[0009] A method of synthesizing jackfruit hydrochar (JFHC) from
jackfruit peel includes subjecting jackfruit peel to hydrothermal
carbonization (HTC) to provide a JFHC. The step of HTC may be
performed at a temperature ranging from about 150.degree. C. to
about 250.degree. C. for a set reaction time of about 30 min to
about 24 hours. The JFHC can be chemically activated. Activation of
the JFHC may include treatment with phosphoric acid
(H.sub.3PO.sub.4, PA) and/or hydrogen peroxide (H.sub.2O.sub.2,
HP). JFHC produced according to the presently disclosed methods
effectively adsorbs MB from an aqueous environment.
[0010] These and other features of the present teachings will
become readily apparent upon further review of the following
specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a reaction scheme for the development and chemical
activation of JFHC@150/3.
[0012] FIG. 2 is a plot showing the Fourier transform infra-red
(FT-IR) spectra of JFHC@150/3, JFHC@150/3_PA, and MB saturated
JFHC@150/3_PA.
[0013] FIG. 3 is a plot showing XPS survey spectra of pristine and
MB saturated JFHC@ 150/3_PA.
[0014] FIGS. 4A-4B shows scanning electron microscopy (SEM) images
of pristine (FIG. 4A) and MB saturated JFHC@150/3_PA (FIG. 4B).
[0015] FIGS. 5A-5B shows energy dispersive X-ray (EDX) spectroscopy
spectra of pristine (FIG. 5A) and MB saturated JFHC@150/3_PA (FIG.
5B).
[0016] FIG. 6 is a plot showing thermogravimetric (TGA-DTA)
analysis of JFHC@ 150/3_PA.
[0017] FIG. 7 is a diagrammatic representation of methylene blue
(MB) adsorption on JFHC@ 150/3_PA.
[0018] FIG. 8 is a plot showing the effect of initial pH (pH.sub.i)
on MB adsorption onto JFHC@ 150/3_PA.
[0019] FIG. 9 is a plot showing the effect of JFHC@150/3_PA dose on
MB adsorption.
[0020] FIG. 10 is a plot illustrating the effect of contact time on
MB adsorption at varied concentrations onto JFHC@150/3_PA.
[0021] FIG. 11 is a plot illustrating equilibrium adsorption
capacity versus equilibrium concentration at varied
temperatures.
[0022] FIG. 12A is a plot presenting adsorption/desorption of MB
from JFHC@150/3_PA by various eluents.
[0023] FIG. 12B is a plot presenting the adsorption/desorption of
MB from JFHC@150/3_PA by HCOOH at varied concentrations.
[0024] Similar reference characters denote corresponding features
consistently throughout the attached drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] A method of synthesizing jackfruit hydrochar (JFHC) from
jackfruit peel includes subjecting jackfruit peel to hydrothermal
carbonization (HTC) to provide an initial JFHC. Preferably the
jackfruit peel is dried and pulverized before being subjected to
HTC. The method of synthesizing JFHC may further include an
activation step to optimize the initial JFHC as an effective
adsorbent for cations, such as methylene blue (MB), from aqueous
environments.
[0026] The step of HTC may be performed at a temperature ranging
from about 150.degree. C. to about 300.degree. C., e.g.,
150.degree. C. to about 250.degree. C. for a set reaction time. The
reaction time can range from about 30 min to about 24 hours.
According to an embodiment, the HTC is performed at a temperature
of about 150.degree. C. for about 3 hours. Activation of the
initial JFHC may include treatment with an activating compound,
such as phosphoric acid (H.sub.3PO.sub.4, PA), hydrogen peroxide
(H.sub.2O.sub.2, HP), or both. Exemplary chemical conditions for
activating the initial JFHC can include treatment with 0.1 N
phosphoric acid (H.sub.3PO.sub.4, PA) or, alternatively, 10%
hydrogen peroxide (H.sub.2O.sub.2, HP). The chemically activated
JFHC sample can then be separated using any suitable method, e.g.,
filtration or centrifugation. For example, filtration can be
conducted using Whatman filter paper 41. JFHC produced according to
the presently disclosed methods effectively adsorbs MB from an
aqueous environment.
[0027] A method of removing MB from an aqueous environment can
include contacting the activated JFHC with the aqueous
environment.
[0028] As used herein, the term "about" when modifying a numerical
value shall mean within 10% of the modified numerical value.
[0029] As described herein, an exemplary JFHC sample exhibiting
maximal MB removal efficiency was prepared by subjecting jackfruit
peel biomass to hydrothermal carbonization at 150.degree. C. for 3
h to provide JFHC, and chemical activation of JFHC with 0.1N PA to
provide an activated JFHC, referred to hereinafter as
"JFHC@150/3_PA". Fourier-transform infrared spectroscopy (FT-IR)
analysis confirmed that phosphate (PO.sub.4.sup.3-) groups were
covalently attached with hydroxyl (--OH) groups during chemical
activation of the JFHC@150/3_PA. The adherence of PO.sub.4.sup.3-
group with JFHC@ 150/3_PA during chemical activation was further
confirmed by X-ray photoelectron spectroscopy (XPS), which revealed
the presence of a spectral peak at 133.7 eV, characteristic of P2p.
After MB adsorption on JFHC@150/3_PA, as described herein, spectral
peaks observed at 401 and 163 eV, attributed to N1s and S2p,
confirmed successful adsorption of MB on JFHC@150/3_PA.
Morphologically, a surface of pristine JFHC@150/3_PA appeared
uneven and porous prior to MB adsorption. Following MB adsorption,
the surface of JFHC@150/3_PA appeared less porous, presumably due
to occupation of pores with MB molecules. A total of 78% weight
loss of the JFHC@150/3_PA sample for a temperature ranging from
30.degree. C.-750.degree. C. was observed during thermogravimetric
analysis (see FIG. 6).
[0030] Maximum MB adsorption (214.7 mg/g) on JFHC@150/3_PA was
observed for an initial pH (pH.sub.i) of 7.24. The MB adsorption
capacity-decreased and % adsorption increased with an increase in
JFHC@150/3_PA dose. The contact time study at varied MB
concentration C.sub.o from 25 mg/L-100 mg/L revealed an increase in
adsorption capacity from 80.8 mg/g to 261.6 mg/g, while the
equilibration time varied between 240 min (4 h) to 360 min (6 h).
The adsorption of MB for C.sub.o in the range: 15 mg/L-150 mg/L
decreased with increase in temperature for the temperature range
20.degree. C.-50.degree. C.
[0031] During the desorption study described in the following
examples, acids (HCl, HCOOH, CH.sub.3COOH) of 0.1 M concentration,
base (NaOH) of 0.1 M concentration and solvents (CH.sub.3OH,
C.sub.2H.sub.5OH, CH.sub.3COCH.sub.3) were used to elute MB from
JFHC@150/3_PA samples. A maximum (40.4%) MB elution was observed
with 0.1 M HCOOH, and increased to 52.6%, with 10-folds (1.0 M)
increase in HCOOH concentration.
Example 1
Synthesis of Jackfruit Peel Hydrochar (JFHC)
[0032] Waste JFP was collected from a local vegetable market in
Saudi Arabia, chopped with a knife into small pieces (.about.1 cm
cube), and dried at 60.degree. C. for a week in an oven. The dried
JFP was washed with deionized (D.I.) water to completely remove any
impurities, such as dirt and dust. The dried and rinsed JFP was
again dried overnight at 60.degree. C. and the dried JFP was
manually crushed using a mortar and pestle. The uniformly crushed
JFP biomass was subjected to HTC in a 200 mL
polytetrafluoroethylene (PTFE) lined autoclave. In a typical HTC
procedure, a slurry of JFP biomass was first made by adding 75 mL
D.I. water to 8 g JFP biomass, and then transferred to an HTC
reactor. The reactor was sealed and heated at 150.degree. C. for 3
h in an oven and was then cooled at room temperature. The sample
(JFHC@150/3) was collected through filtration and washed several
times with D.I. water to remove unwanted products generated during
the HTC process. FIG. 1 schematically shows the method of
synthesizing JFHC@150/3. Analogous embodiments of the present
method were used to synthesize JFHC samples at 200.degree. C.
(JFHC@200/3) and 250.degree. C. (JFHC@250/3).
Example 2
Chemical Activation of Developed JFHC Samples
[0033] The developed JFHC samples (JFHC@150/3, JFHC@200/3 and
JFHC@250/3) were chemically activated with phosphoric acid (0.1 N
H.sub.3PO.sub.4; PA), hydrogen peroxide (10% H.sub.2O.sub.2; HP),
and a phosphoric acid+hydrogen peroxide (0.1N H.sub.3PO.sub.4+10%
H.sub.2O.sub.2: PA+HP) mixture. One gram of JFHC@150/3 was treated
separately with either 50 mL PA (JFHC@150/3_PA), 50 mL HP
(JFHC@150/3_HP), or 50 mL PA+HP (JFHC@150/3_PA_HP) with stirring by
a magnetic stirrer at 200 rpm for an hour. The resulting chemically
activated samples were separated, e.g., through filtration, and
washed several times with D.I. water until a neutral pH of the JFHC
rinse water was achieved. All three samples were dried overnight at
80.degree. C. in an oven. The same activation protocols for
chemical activation were performed on the JFHC@200/3 and JFHC@250/3
samples. The nomenclature of the resulting synthesized JFHC samples
is given in Table 1. FIG. 1 illustrates the JFHC@150/3 activation
with PA through covalent bond formation.
TABLE-US-00001 TABLE 1 Hydrothermal carbonization and chemical
activation conditions, nomenclature, and MB adsorption on JFHC
samples S4 sample selected for detailed MB adsorption studies. HTC
Conditions MB S. No. Temp (.degree. C.) Time (h) Chemical Treatment
Nomenclature adsorption (%) S1 150 3 Untreated JFHC@150/3 93.3 S2
200 3 Untreated JFHC@200/3 92.4 S3 250 3 Untreated JFHC@250/3 92.4
S4 150 3 0.1N H.sub.3PO.sub.4 JFHC@150/3_PA 99.5 S5 200 3 0.1N
H.sub.3PO.sub.4 JFHC@200/3_PA 98.5 S6 250 3 0.1N H.sub.3PO.sub.4
JFHC@250/3_PA 98.6 S7 150 3 10% H.sub.2O.sub.2 JFHC@150/3_HP 99.0
S8 200 3 10% H.sub.2O.sub.2 JFHC@200/3_HP 98.6 S9 250 3 10%
H.sub.2O.sub.2 JFHC@250/3_HP 98.8 S10 150 3 0.1N H.sub.3PO.sub.4 +
10% H.sub.2O.sub.2 JFHC@150/3_PA_HP 99.1 S11 200 3 0.1N
H.sub.3PO.sub.4 + 10% H.sub.2O.sub.2 JFHC@250/3_PA_HP 98.8 S12 250
3 0.1N H.sub.3PO.sub.4 + 10% H.sub.2O.sub.2 JFHC@250/3_PA_HP
99.1
Example 3
Characterization of Developed and Chemically Activated JFHC
Samples, and Presumed MB Adsorption Mechanism
[0034] The functional groups present on the pristine JFHC@150/3 and
JFHC@150/3_PA samples and involved during MB adsorption on
JFHC@150/3_PA were detected by FT-IR (Nicolet 6700, Thermo
Scientific, USA) spectroscopic analysis, as illustrated in FIG. 2.
A band at 3443 cm.sup.-1 was attributed to hydroxyl (--OH) group
stretching vibrations (Wang et al., 2017). Two adjacent bands at
2827 cm.sup.-1 and 2928 cm.sup.-1 were attributed to symmetric and
asymmetric vibrations of C--H groups (Wang et al., 2017). A band at
1733 cm.sup.-1 was attributed to carbonyl (C.dbd.O) group
stretching vibrations in ester and acetyl linkages in hemicellulose
and lignin. Bands at 1622 cm.sup.-1 and 1519 cm.sup.-1 were
associated with the aromatic ring present in lignin. The bands at
1053 cm.sup.-1 and 1159 cm.sup.-1 were associated with C--O--C
stretching vibrations in cellulose. After chemical activation of
JFHC@ 150/3 with PA, a band in range: 973 cm.sup.-1-1100 cm.sup.-1,
characteristic of phosphate (PO.sub.4.sup.3-) group appeared
(Roguska et al., 2011). However, this band was overlapped with
signal from C--O--C groups, confirmed by a decrease in band size.
Additionally, PO.sub.4.sup.3- groups were covalently attached with
--OH groups present on JFHC@150/3 during chemical activation,
confirmed by a decrease in band size due to dehydration. After MB
adsorption on JFHC@150/3_PA, the bands at 1059 cm.sup.-1 and 3443
cm.sup.-1 were shifted to 1040 cm.sup.-1 and 3431 cm.sup.-1 with a
decrease in their respective sizes.
[0035] The chemical composition of pristine and MB saturated
JFHC@150/3_PA were characterized by XPS (Joel JPS-9200, Japan)
analysis. FIG. 3 shows the spectrum resulting from pristine
JFHC@150/3_PA, with three peaks at 531 eV, 284.6 eV and 133.7 eV,
attributable to O1s, C1s, and P2p, respectively. Two new peaks at
401 eV and 163 eV attributed to N1s and S2p appear in the spectrum
of MB saturated JFHC@150/3_PA. The appearance of N1s and S2p peaks
in the MB saturated JFHC@150/3_PA spectrum is consistent with MB
adsorption onto the JFHC@150/3_PA surface.
[0036] The morphology and elemental content of pristine and MB
saturated JFHC@150/3_PA were determined by scanning electron
microscopy (SEM: Nova 200 NanoLab, FEI, USA) coupled with
energy-dispersive X-ray (EDX: AMETEK Nova 200) spectroscopic
analysis. FIG. 4A shows an uneven and irregular pristine
JFHC@150/3_PA surface, with evident pores. After MB adsorption, the
JFHC@150/3_PA surface appears smoother with less apparent pores
(FIG. 4B), presumably due to the formation of an MB film over the
surface. The elemental analysis spectrum and elemental mapping
image of JFHC@ 150/3_PA (FIG. 5A) shows traces of phosphorus,
confirming successful chemical modification of JFHC@150/3 surface
with PA. After MB adsorption on JFHC@150/3_PA, traces of nitrogen
and sulfur were present in the elemental analysis spectrum,
confirming attachment of MB to the JFHC@150/3_PA surface (FIG.
5B).
[0037] Thermogravimetric analysis of JFHC@150/3_PA was performed
(TGA-DTA: Q500 TGA, USA) at temperatures ranging from 30.degree.
C.-750.degree. C. under N.sub.2 atmosphere. FIG. 6 shows 4% weight
loss as temperature increases from 30.degree. C.-100.degree. C.,
presumably due to evaporation of physically adsorbed water
molecules from the JFHC@150/3_PA. A drastic 60% weight loss of
JFHC@150/3_PA occurred between 250.degree. C. and 400.degree. C.,
presumably due to the decomposition of cellulose, hemicellulose and
lignin typical of plant biomass. Furthermore, 14% weight loss
occurred between temperatures ranging from 400.degree. C. to
750.degree. C., presumably due to degradation of lignin.
[0038] FIG. 7 diagrammatically shows possible mechanisms for
adsorption of MB on JFHC@ 150/3_PA, including formation of hydrogen
bonds between --OH groups present on JFHC@150/3_PA and
dimethylamino (--N(CH.sub.3).sub.2) groups of MB dye, electrostatic
interactions between the electron rich oxygen atoms on
JFHC@150/3_PA and MB cations, and .pi.-.pi. stacking interactions
between the aromatic rings of JFHC@150/3_PA and MB dye.
Example 4
Adsorption Experiments and Results
[0039] Preliminary studies were carried out to evaluate performance
among the pristine and chemically activated JFHC samples for
maximum MB removal efficiency. Batch scale adsorption experiments
were carried out in 100 mL Erlenmeyer flasks, containing 25 mL MB
solution of initial concentration (C.sub.o). 20 mg/L was
equilibrated with 0.01 g each pristine or chemically activated JFHC
sample, under shaking conditions at 80 rpm for 24 h. Once
equilibrium was reached, solid (JFHC sample) and solution (MB
solution) phases were separated through filtration and the residual
MB concentration was analyzed by UV-visible spectrometry (Thermo
Scientific Evolution 600, UK) at a maximum wave length
(.lamda..sub.max) of 665 nm. The adsorption of MB on JFHC was
calculated as:
Adsorption ( % ) = C 0 - C e C 0 .times. 100 ( 1 ) ##EQU00001##
[0040] The observed MB adsorptions (in %) for each JFHC sample is
provided in Table 1 (under Example 2). The effect of variables
viz., pH, contact time (1), temperature (T), dose (m), initial
concentration (C.sub.o) on MB adsorption onto JFHC@150/3_PA (sample
with maximum (99.5%) MB removal) were further studied and MB
adsorption capacities at equilibrium and at any time t were
calculated as:
Adsorption capacity at equilibrium ( q e , mg / g ) = ( C 0 - C e )
.times. V m ( 2 ) Adsorption capacity at time t ( q t , mg / g ) =
( C 0 - C t ) .times. V m ( 3 ) ##EQU00002##
[0041] The adsorption of MB at C.sub.o: 50 mg/L on JFHC@150/3_PA as
a function of pH.sub.i is illustrated in FIG. 8. The MB adsorption
capacity was 74 mg/g at pH.sub.i: 2.7, sharply increased to 210.4
mg/g at pH.sub.i: 5, then slowly increased, reaching a measured
maximum of 214.7 mg/g at pH.sub.i: 7.2.
[0042] The adsorption of MB at C.sub.o: 50 mg/L was studied by
varying JFHC@150/3_PA dose, as illustrated in FIG. 9. For doses in
the range of 0.01 g-0.1 g, the MB adsorption capacity decreased
from 195.3 mg/g to 24.9 mg/g, while the percentage (%) adsorption
increased from 78% to 99.7%.
[0043] The adsorption of MB on JFHC@150/3_PA as a function of
contact time was studied at varied MB C.sub.o ranging from 25
mg/L-100 mg/L, as illustrated in FIG. 10. For an initial 30 minutes
of contact time, a sharp increase in MB adsorption was observed.
Thereafter, the adsorption process approached an equilibrium. The
equilibration time for the studied C.sub.o values varied from 360
min (6 h) to 480 min (8 h).
[0044] FIG. 11 shows equilibrium concentration (C.sub.e) versus
adsorption capacity at equilibrium (q.sub.e) for MB adsorption on
JFHC@150/3_PA at varied temperatures. The MB adsorption on
JFHC@150/3_PA decreased with increase in temperature, consistent
with exothermic MB adsorption.
Example 5
Desorption Experiments and Results
[0045] The regeneration potential of JFHC@150/3_PA was tested
through batch scale desorption experiments. The MB saturated
JFHC@150/3_PA samples described in Example 4 were washed several
times with D.I. water to completely remove unadsorbed MB.
Thereafter, the saturated JFHC@150/3_PA samples were treated with
one of several eluents chosen from a group of solvents and 0.1 M
base or acid solutions. The amount of MB desorbed was calculated
as:
Desorption ( % ) = Concentration of MB desorbed by eluent Initial
concentration of MB absorbed on JFHC @ 150 / 3 _PA .times. 100 ( 4
) ##EQU00003##
[0046] FIG. 12A shows maximum (40.4%) MB desorption was observed
following treatment with 0.1 M HCOOH. Among the other eluents
tested, MB desorption percentage followed the trend: 0.1M
CH.sub.3COOH>0.1M
HCl>CH.sub.3OH>CH.sub.3COCH.sub.3>C.sub.2H.sub.5OH>0.1M
NaOH. The effect of HCOOH concentration on MB recovery from the
saturated JFHC@150/3_PA samples is illustrated in FIG. 12B. The MB
desorption increased with increasing HCOOH concentration from 0.05
M to 1.0 M, achieving a maximum desorption of 52.6%.
[0047] It is to be understood that the method of synthesizing
hydrochar from jackfruit is not limited to the specific embodiments
described above, but encompasses any and all embodiments within the
scope of the generic language of the following claims enabled by
the embodiments described herein, or otherwise shown in the
drawings or described above in terms sufficient to enable one of
ordinary skill in the art to make and use the claimed subject
matter.
* * * * *