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American Journal of  
Chemistry and Pharmacy (AJCP)

Multidisciplinary Assessment of  Adsorption Kinetics and Isotherm Modeling of  Crude 
Oil Removal Using Agro-Waste-Derived Nanomaterials: An Integrative Approach with 

Sonographic, Medical, Biochemical, and Analytical Perspectives
S. I. Okonkwo1*, O. S. Ochie2, I. P Oragwu1, C. K. Okonkwo3, P. O. Okwuego1, A. T. Kene Okonkwo4, V. S. Okonkwo5,

S. C. Okonkwo6

Volume 4 Issue 2, Year 2025
ISSN: 2834-0116 (Online)

DOI: https://doi.org/10.54536/ajcp.v4i2.5342
https://journals.e-palli.com/home/index.php/ajcp

Article Information ABSTRACT

Received: May 15, 2025
Accepted: June 20, 2025
Published: December 13, 2025

Crude oil spills are an increasingly urgent global concern due to their profound 
environmental and public health consequences. This study investigates the potential of  
agro-waste-derived nanostructured sorbent specifically synthesized from rice and melon 
husks for the remediation of  crude oil-contaminated water. Using a multidisciplinary 
framework, the research incorporates analytical chemistry, biochemistry, sonography, and 
medical diagnostics to assess both the efficiency and biomedical safety of  the nanomaterials. 
Adsorption experiments for Premium Motor Spirit (PMS) were conducted. Characterization 
using Brunauer–Emmett–Teller (BET)  and Fourier Transform Infrared Spectroscopy 
(FTIR) analysis revealed high porosity, favorable surface morphology, and the presence of  
polar functional groups that enhance sorption. Kinetic modeling followed pseudo-second-
order kinetics, confirming chemisorption, while Langmuir isotherm modeling demonstrated 
monolayer adsorption on homogeneous surfaces.Toxicological evaluation was carried out 
on albino rats grouped into control, oil-exposed, and remediated water cohorts. Biochemical 
markers such as ALT (Alanine Transaminase), AST (Aspartate Transaminase), creatinine, 
and urea levels were measured to assess hepatic and renal function. Elevated enzyme 
levels in oil-exposed rats (ALT: 120 IU/L; AST: 145 IU/L; Creatinine: 2.6 mg/dL) were 
significantly reduced post-treatment (ALT: 52 IU/L; AST: 65 IU/L; Creatinine: 1.3 mg/
dL), approaching control values (p < 0.05). Sonographic scans indicated hepatomegaly and 
hyperechogenicity in contaminated groups, while remediated groups showed normalization 
of  liver and kidney echotexture. Medical analysis concluded that the sorbents not only 
removed toxic hydrocarbons but also reversed or prevented hepatic and renal structural 
damage.This integrative study underscores the synergistic value of  combining environmental 
nanotechnology with clinical diagnostics. The results validate the potential of  using rice 
and melon husk-derived nanomaterials as eco-friendly, cost-effective, and biologically safe 
options for crude oil remediation.

Keywords
Agro-Waste, ALT, AST, 
BET, Crude Oil Remediation, 
FTIR, Langmuir Isotherm, 
Nanostructured Sorbents, Pseudo-
Second-Order Kinetics, Sonography

1 Department of  Pure and Industrial Chemistry, Chukwuemeka Odumegwu  Ojukwu University, Uli, Anambra State, Nigeria
2 Food Safety and Applied Nutrition Directorate, National Food and Drug Administration and Control (NAFDAC), Owerri, Nigeria
3 Department of  Diagnostic Medical Sonography and Ultrasound Technology, Ace Institute of  Technology, Elmhurst, New York, USA
4 Tansian University Oba, Anambra State, Nigeria
5 Department of  Medical Biochemistry, Chukwuemeka Odumegwu Ojukwu University, Uli, Nigeria
6 Department of  Pharmacology, Chukwuemeka Odumegwu Ojukwu University, Nigeria
* Corresponding author’s e-mail: si.okonkwo@coou.edu.ng

INTRODUCTION
Crude oil remains one of  the most widely used fossil 
fuels, contributing significantly to global energy supply. 
However, crude oil spills, particularly in developing 
countries like Nigeria, pose acute risks to the environment 
and public health (Nwilo & Badejo, 2005). The Niger 
Delta, known for its rich biodiversity, has been a hotspot 
for frequent oil spill incidents due to pipeline vandalism, 
illegal refining, and inadequate spill response mechanisms 
(UNDP, 2006).
Previous research has documented the toxic effects 
of  hydrocarbons on aquatic life, soil productivity, and 
human health. Inhalation or ingestion of  petroleum-
contaminated water is linked to hepatic dysfunction, 
nephrotoxicity, carcinogenesis, and endocrine disruption 
(WHO, 2021). The detection of  these pathologies is 
now greatly enhanced through sonographic imaging 
and biochemical assays (Olatunde et al., 2020). This 

study bridges the gap between environmental science 
and medical diagnostics by evaluating the environmental 
efficacy and health impact of  nano-sorbents derived from 
rice and melon husks.
Rice and melon husks are rich in cellulose, hemicellulose, 
and lignin, which offer numerous active sites for chemical 
modifications. These agro-wastes, when processed 
into nano-scale particles, significantly increase surface 
area and reactivity (Elemike et al., 2022; Chukwu et al., 
2021). Nanomaterials derived from agro-waste have 
demonstrated exceptional adsorption properties for 
pollutants, including heavy metals, dyes, and hydrocarbons 
(Kumar et al., 2019).
oil contamination has been associated with elevated 
serum levels of  ALT and AST due to hepatic injury 
(Olatunde et al., 2020). Similarly, raised urea and creatinine 
levels indicate compromised kidney function. Ultrasound 
imaging, particularly in preclinical trials, is a non-invasive 



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Am. J. Chem. Pharm. 4(2) 16-20, 2025

and effective method for monitoring internal organ 
morphology (Ibeabuchi et al., 2022). However, few studies 
integrate nanotechnology, adsorption modeling, and 
biomedical safety testing in a single research framework.

MATERIALS AND METHODS
Sorbent Preparation
The Rice and melon husk material were washed with 
distilled water to remove dirt, dust or any other impurities. 
The materials were dried in an oven at 60-80°C until 
they were completely dried. The dried melon and rice 
husk were grinded into fine powder using a grinder. The 
ground materials were sieved to ensure that uniform 
particles between 50-100 microns were obtained. Exactly 
500 ml of  0.5 mol of  NaOH was added into washed, 
dried and ground rice and melon husks weighing 81 g and 
73 g respectively in separate batches. Precipitate of  nano 
sized particles of  melon and rice husk were obtained. The 
nano sized particles of  melon and rice husk formed were 
collected and dried in an oven

Characterization
Brunauer–Emmett–Teller (BET) Analysis
Exactly 0.5 g of  the finely grinded sample was placed 
into a sample tube designed for BET analysis. The 
sample was degassed on 200°C for 4 hours by heating 
it under vacuum. This step was critical to remove any 
adsorbed gases and moisture that could interfere with 
the BET measurements(Ochie et al., 2024). The BET 
instrument was turned on and was allowed to stabilize. 
The instrument was calibrated and properly functioning. 
The gas supply was connected and flowing at the correct 
pressure. The degassed sample was loaded to the sample 
tube into the BET instrument sample holder (Ochie et 
al., 2024). The sample tube was properly sealed in the 
analysis chamber, and the system was under inert gas 
flow to avoid contamination from ambient air. Nitrogen 
gas was used as the adsorbate, which interacts with the 
surface of  the material to measure the surface area. The 
pressure range was set to 0.3 of  the adsorbate gas. The 
instrument introduced nitrogen gas into the chamber in 
controlled amounts, allowing it to adsorb onto the surface 
of  the sample at different pressures (Ochie et al., 2024). 
The BET analyzer recorded the amount of  gas adsorbed 
and desorbed at different pressures, generating data that 
describes the material’s surface area and porosity. After 
the completion of  the analysis, the system generated an 
adsorption-desorption isotherm, which is a plot of  the 
amount of  gas adsorbed versus the relative pressure. 

Fourier Transform Infrared Spectroscopy (FTIR)
Exactly 0.2 g of  melon and rice husk sorbent was grinded 
using mortar and pestle in order to finely grind, which 
ensured uniformity and increased the surface area for 
better IR interaction. 100 mg of  potassium bromide 
(KBr) was introduced 2mg of  the powdered sample to 
form a fine powder. The KBr and sample mixture was 
pressed into a pellet using a pellet press which created a 

transparent disc for analysis (Ochie et al., 2024). The FTIR 
spectrometer was turned on and allowed to warm up, 
the instrument was calibrated without the sample which 
helped to eliminate any noise from the environment. 
The mode was selected. Each of  the samples were put 
in the FTIR sample holder and it was scanned such that 
the wavelength was typically 4000 cm–1 to 400 cm–1, the 
resolution was 4 cm–1 and the number of  scan was 16-32 
scans for a clear spectrum.The instrument infrared light 
absorbed by the sample at different wave length.

Adsorption Studies
Exactly 0.5 g mass of  the nano-sorbent was added to each 
solution with varying oil concentrations. The mixtures 
were stirred and allowed to reach equilibrium after 1 hour. 
After equilibrium, the remaining oil concentration in each 
solution was measured using UV-Vis spectroscopy and 
gravimetric methods. The amount of  oil adsorbed per 
unit mass of  the nano-sorbent (q) was calculated for each 
initial oil concentration. The equilibrium data were plotted 
asq versus C e (the equilibrium concentration of  oil in the 
solution). The experimental data were fitted to isotherm 
models like Langmuir and Freundlich isotherms. The 
isotherm parameters (q max, K L, K ) were determined 
by fitting the data to these models.

Kinetics Studies
A solution with 100 mg/L concentration of  oil was 
prepared. Exactly 0.5 g of  nano-sorbent was added to 
the oil-water solution, and samples were taken at different 
time intervals 10minutes). The concentration of  residual 
oil in the water phase was measured at each time interval 
using UV-Vis spectroscopy. The amount of  oil adsorbed 
at each time interval was calculated, and the data were 
plotted as q versus time. The experimental data were 
fitted to kinetics models like:Pseudo-First-Order Kinetics 
and Pseudo-Second-Order Kinetics

In Vivo Toxicological Assessment
The study involved 15 Wistar albino rats, weighing between 
200-250g, which were divided into three groups: Group 
A served as the control group and received clean water, 
Group B was exposed to crude oil-contaminated water, 
and Group C received remediated water treated with nano-
sorbents, with the experiment lasting for 21 days.

Biochemical Assays
The methodology for biochemical assays using Roche 
Diagnostics kits for ALT, AST, Creatinine, and Urea 
involves kinetic assays for ALT and AST, enzymatic 
assays for Creatinine and Urea, and utilizes Roche’s 
analyzers such as the Cobas c311, with calibration and 
quality control materials run to ensure assay accuracy and 
precision, providing accurate and precise results, high 
throughput, and ease of  use.
For these assays, plasma samples are prepared according 
to Roche’s guidelines, and reagents are prepared according 
to the kit instructions, with samples and reagents then 



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Am. J. Chem. Pharm. 4(2) 16-20, 2025

pipetted into designated wells or cuvettes and run on the 
analyzer, which measures absorbance or fluorescence 
changes proportional to enzyme activity or analyte 
concentration.

Sonographic Imaging
Ultrasound examinations were conducted before and after 
treatment using a portable ultrasound device, focusing on 
assessing liver size, echotexture, and renal cortex integrity.

Statistical Analysis
Statistical analysis was performed using analysis of  
variance (ANOVA) followed by Tukey’s post-hoc test, 
with a significance level set at p < 0.05.

RESULTS AND DISCUSSION
The nano rice husk sorbent exhibits a high surface area 

of  680.5 m²/g (BET) and 999.9 m²/g (Single Point), a 
microporous structure with a t-Plot Micropore Area of  
20.4 m²/g and Micropore Volume of  0.13044 cm³/g, 
a narrow pore size distribution with an average pore 
width of  30.34 Å to 30.42 Å, and a high pore volume 
of  0.6035 cm³/g (Single Point) and 0.52222 cm³/g (BJH 
Desorption).
Similarly, the nano melon sorbent has a high surface area 
of  460.36 m²/g (BET) and 999.90 m²/g (Single Point), a 
microporous structure with a t-Plot Micropore Area of  
20.30 m²/g and Micropore Volume of  0.13044 cm³/g, 
a narrow pore size distribution with an average pore 
width of  30.34 Å to 30.42 Å, and a high pore volume 
of  0.6035 cm³/g (Single Point) and 0.52222 cm³/g 
(BJH Desorption), indicating its potential for efficient 
adsorption, selective adsorption, and applications in 
various fields.

Table 1: Findings from the Brunauer–Emmett–Teller (BET) analysis
Property  Nano Melon Husk Sorbent Nano Rice Husk Sorbent (Ochie et al., 2024)
BET Surface Area 460.36 m2/g 680.5 m2/g
Langmuir Surface Area 50.24 m2/g 52.24 m2/g
Micropore Area 20.3 m2/g 20.4 m2/g
Pore Volume 0.6035 cm3/g 0.6035 cm3/g
Average Pore Width 30.34 Å 30.34 Å

FTIR Analysis Findings for Rice Husk and Melon 
Husk Nano-Sorbents
The Fourier Transform Infrared (FTIR) spectra of  nano-

sorbents derived from rice husk and melon husk reveal the 
presence of  various functional groups, including hydroxyl 
groups (–OH) indicated by broad peaks around 3439 

Figure 1:  Fourier Transform Infrared (FTIR) graph for Rice Husk and Melon Husk Nano-Sorbents

cm-¹ for rice husk and 3300 cm-¹ for melon husk, aliphatic 
hydrocarbons (C-H stretching) at 2926 cm-¹ for rice husk 
and 2900 cm-¹ for melon husk, carbonyl and carboxyl 
groups (C=O stretching) at 1728 cm-¹ for rice husk and 
1700–1600 cm-¹ for melon husk, aromatic rings and C=C 
stretching at 1637–1514 cm-¹ for rice husk and 1500 
cm-¹ for melon husk, and polysaccharide backbone (C-O 
stretching) at 1256–1039 cm-¹ for rice husk and 1200–
1000 cm-¹ for melon husk. The rice husk nano-sorbent 
shows an additional peak at 1039 cm-¹ related to Si-O-Si 
stretching, confirming the presence of  silica, and a peak 

at 2369 cm-¹ likely due to atmospheric CO₂ or processing 
artifacts. The melon husk nano-sorbent exhibits distinct 
low-frequency peaks around 800–600 cm-¹ attributed to 
aromatic C-H bending and possible inorganic impurities, 
such as silicates. These functional groups, including 
hydroxyl, carbonyl, carboxyl, aliphatic, aromatic, and 
polysaccharide-derived groups, enable diverse interaction 
mechanisms such as hydrogen bonding, ion exchange, 
π-π stacking, and van der Waals forces with organic and 
inorganic pollutants, enhancing their potential as eco-
friendly, low-cost, and efficient nano-sorbents for the 



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remediation of  crude oil-contaminated water and soils.

Findings from Sorption Experiments Using Both 
Sorbents for PMS  
The sorption experiment aimed to evaluate the 
effectiveness of  nano rice husk and nano melon husk in 
removing Premium Motor Spirit (PMS) from water.

Volume of  PMS= 100mL
Mass of  melon husk before Sorption = 1.00 g
Mass of  rice husk before Sorption = 1.00 g
Mass of  melon husk after Sorption = 1.340 g
Mass of  rice husk after Sorption = 1.338 g
Sorption Capacity for melon husk = 1.340 – 1.00 g = 0.340 g
Sorption Capacity for rice husk = 1.338 – 1.00 g = 0.338 g

Figure 2: Kinetics graph of  PMS removal using rice husk and melon husk sorbents

Both nano melon husk and nano rice husk demonstrated 
significant PMS sorption capacities, with melon husk 
showing a slightly higher capacity (0.340 g) compared to 
rice husk (0.338 g). The sorption efficiencies of  melon 
husk and rice husk are 34.0% and 33.8%, respectively, 
indicating their potential for PMS removal from water. 
The results shows that nano melon husk and nano rice 
husk have comparable sorption capacities for PMS, 
with minimal difference between them. The sorption 

mechanism involves physical adsorption, chemical 
adsorption, facilitated by the high surface area and porous 
structure of  the nano sorbents.

Considerations of  the Kinetic Studies of  PMS Using 
Both Sorbents
The kinetic model fitting results for both pseudo-first-
order and pseudo-second-order models are plotted above 
for rice husk and melon husk sorbents.

Table 2: Data from sorption experiments using premium motor spirit (PMS)
Sorbent Initial Mass (g) Final Mass (g) Sorption Capacity (g)
Melon husk nano-sorbent 1.00 1.340 0.340
Rice husk nano-sorbent 1.00 1.338 0.338

Table 3: Kinetic model fitting results
Pseudo First Order

qe k1

Rice Husk 0.0148 3.19
Melon Husk 0.0228 9.66 x 108 g/mg/s
Pseudo Second Order

qe k2

Rice Husk 0.0148 3.19
Melon Husk 0.0228 2.13 x 10-8 g/mg/s

Both models exhibit very similar fits, with the second-
order model following closely along the observed data, 
but both models show a minimal change in absorbance 
over time, indicating a rapid equilibrium is reached.
Pseudo-second-order model fits better, as it follows the 
observed decline in absorbance more closely. The pseudo-
second-order model generally implies that chemisorption 
is the rate-limiting step. For rice husk, the fast plateauing 
of  absorbance shows a rapid adsorption process, which 

point to physical adsorption (physisorption) being 
dominant. For melon husk, the continuous decline in 
absorbance and better fit of  the second-order model 
shows a more gradual adsorption process, which is due 
to chemical bonding between PMS and the surface of  
the sorbent (chemisorption). The results shows that 
melon husk have a slower but more sustained adsorption, 
potentially offering higher capacity, while rice husk 
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Biochemical Findings
Group B exhibited elevated liver enzymes and renal 
markers, with alanine transaminase (ALT) levels at 120 
IU/L, aspartate transaminase (AST) at 145 IU/L, and 
creatinine at 2.6 mg/dL, which improved post-treatment 
in Group C, with ALT decreasing to 52 IU/L, AST to 65 
IU/L, and creatinine to 1.3 mg/dL, approaching values 
similar to the control group, which had ALT at 45 IU/L, 
AST at 58 IU/L, and creatinine at 1.1 mg/dL.

Sonographic Findings
Group B exhibited hepatomegaly and hypoechoic liver 
parenchyma with a dilated renal pelvis, whereas Group 
C demonstrated regression in liver size, normalized 
echogenicity, and restored cortical thickness, indicating 
significant improvement.

Medical Interpretation
Oil exposure causes hepatocellular and nephronal 
damage, evident through enzyme elevation and structural 
distortion.
Nano-sorbent remediation reversed hepatic and renal 
abnormalities both functionally and structurally.

CONCLUSION
This study has demonstrated that agro-waste-derived 
nano-sorbents from rice and melon husks possess 
excellent physicochemical properties, including high 
surface area, favorable pore characteristics, and 
functional groups conducive to adsorption. Their 
efficacy in removing crude oil from contaminated water 
was affirmed through sorption capacity measurements 
and isotherm/kinetic modeling, with results indicating 
a dominance of  chemisorption governed by pseudo-
second-order kinetics. The Langmuir isotherm model 
also confirmed monolayer adsorption on homogeneous 
surfaces. Beyond their environmental performance, 
the biomedical assessments revealed a significant 
reversal of  hepatotoxicity and nephrotoxicity in oil-
exposed rats treated with remediated water. Biochemical 
markers such as ALT, AST, and creatinine showed 
marked improvement post-treatment, corroborated by 

sonographic normalization of  liver and kidney structures. 
This underscores the biocompatibility and therapeutic 
safety of  the nano-sorbents.

Recommendations
● Adopt agro-waste-derived nano-sorbents in rural 

and urban water treatment programs.
● Incorporate biomedical testing (sonography, ALT/

AST) in water remediation evaluations.
● Promote interdisciplinary research to address 

pollution and public health holistically.
● Encourage policy incentives for waste-to-resource 

innovations.

REFERENCES
Chukwu, A., Okoye, P. A., & Afolabi, A. (2021). Synthesis 

of  nano-sorbents from agricultural by-products. 
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Elemike, H. E. (2022). Agricultural waste valorization for 
nanomaterial synthesis. Environmental Nanotechnology, 
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Freundlich, H. (1906). Over the adsorption in solution. 
Zeitschrift für Physikalische Chemie, 57, 385–470.

Ibeabuchi, N. (2022). Sonographic evaluation of  
pollutant-induced hepatotoxicity in Wistar rats. West 
African Journal of  Radiology, 29(2), 150–157.

Kumar, P. S. (2019). Adsorption of  pollutants using agro-
based nanomaterials. Journal of  Cleaner Production, 223, 
1234–1245.

Langmuir, I. (1918). The adsorption of  gases on plane 
surfaces of  glass. Journal of  the American Chemical 
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Nwilo, P. C., & Badejo, O. T. (2005). Oil spill problems and 
management in the Niger Delta. Int. Ocean Inst.

Olatunde, A. A. (2020). Clinical and biochemical profile 
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Journal of  Medical Sciences, 19(3), 78–84.

UNDP. (2006). Niger Delta Human Development Report. 
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WHO. (2021). Global Chemical Safety and Petroleum Pollution. 
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