INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN APPLIED SCIENCE (IJRIAS)  
ISSN No. 2454-6194 | DOI: 10.51584/IJRIAS |Volume X Issue XI November 2025  
Modified Orange Peels Biochar as a Sustainable Green Biosorbents for  
Nitrates and Phosphates in Environmental Waters  
Otieno Winstone Ochieng*., Gerald Wachira Mbugua., Otieno Kevin Okoth  
Faculty of Biological and Physical Science, Tom Mboya University, P.O. Box 199-40300, Homa Bay,  
Kenya  
*Corresponding Author  
DOI: https://doi.org/10.51584/IJRIAS.2025.101100076  
Received: 28 November 2025; Accepted: 04 December 2025; Published: 18 December 2025  
ABSTRACT  
Biomass waste utilization has garnered a lot of interest lately, particularly in the purification of environmental  
water. Water pollution caused by excessive nitrates has become a significant environmental concern globally.  
The traditional treatment methods often involve costly and energy-intensive processes. This chapter examines  
the potential of using modified fruit peels, specifically modified orange peels biochars, as natural bio sorbents  
for the removal of nitrates and phosphates from environmental waters. Biochar, a charcoal-like material  
produced by heating biomass in an oxygen limited environment, has emerged as a promising tool for water  
purification due to its unique properties and environmental advantages. Its microporous structure offers a vast  
surface area decorated with functional groups, ideal for capturing contaminants such as the phosphates and the  
nitrates. Biochar's purification power works through a combination of mechanisms. It acts like a sponge, using  
its porous structure to trap contaminants physically through adsorption. The charged functional groups on its  
surface also act like magnets, attracting and holding onto unwanted ions through ion exchange. Scientists rely  
on mathematical models like Langmuir and Freundlich isotherms to fully understand how well biochar will work  
in a particular situation. These models describe how efficiently biochar removes contaminants at varying  
concentrations either through monolayer adsorption route on homogenous surfaces as in the case of Langmuir  
or onto heterogenous surfaces as in the case of Freundlich isotherm, providing valuable insights for optimizing  
biochar-based water treatment systems.  
Key words: Green bio sorbents, Biochars, modified orange peel biochars, Biosorption, water treatment methods,  
Water pollution, Adsorption and Mechanisms.  
Graphical abstract  
INTRODUCTION  
There are substantial amounts of industrial and agricultural waste products as a result of the increase in industrial  
activity and population growth. When these pollutants and effluents are improperly disposed of, the environment  
and human health are gravely threatened. (Chowdhury and Balasubramanian, 2014; Lata and Samadder, 2016).  
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Due to this, the water and wastewater treatment industry's top priorities now include guaranteeing a clean water  
supply and enhancing water quality. A vital requirement for public health, access to safe drinking water is denied  
to an estimated 1.2 billion people in poor nations. Limited access to sanitary facilities for 2.6 billion people  
exacerbates the situation even more. It is frequently not possible to completely eliminate these pollutants using  
conventional water treatment procedures (Bao et al., 2017)considerations for bio sorbents have been on the rise  
by researchers and scientist.  
Bio sorbents are natural or modified materials that have the ability to remove pollutants from water through a  
process called biosorption (Rangabhashiyam et al., 2014). Biosorption is a promising and environmentally  
friendly method of water treatment that utilizes the binding capacity of certain natural materials to remove  
various contaminants. One such group of bio sorbents are fruit peels, specifically banana peels and orange peels.  
Banana peels and orange peels are readily available agricultural waste products that have gained attention as  
potential bio sorbents due to their abundance, cost-effectiveness, and beneficial properties. These fruit peels  
contain compounds, such as potassium, phosphorus, and limonene, that exhibit sorption capacities for  
contaminants commonly found in water, including nitrates, phosphates, and certain organic compounds.  
Studies have shown that the surface of orange peels can undergo chemical modifications to enhance their  
sorption capabilities. These modifications can include physical/chemical treatments such as drying, grinding,  
and activation processes. Additionally, combining these biosorption methods with other treatment technologies,  
like filtration or membrane processes, can improve their overall efficiency. Biosorption using modified fruit  
peels offers several advantages over conventional water treatment methods. It is a renewable, low-cost  
technology with reduced energy requirements compared to other treatment processes. Moreover, bio sorbents  
derived from fruit peels are biodegradable, potentially reducing waste disposal issues associated with their  
disposal and contributing to sustainable practices.  
Nitrates is common types of chemical compounds that can be found in water sources(Bhatnagar and Sillanpää,  
2011). It is one forms of nutrients that can have significant impacts on water quality and the health of aquatic  
-
ecosystems. Nitrates are a combination of nitrogen and oxygen (NO3 ) that can enter water bodies through a  
variety of sources, including agricultural runoff, sewage, and the use of fertilizers. While nitrogen is an essential  
nutrient for plant growth, excessive amounts of nitrates in water can lead to nutrient pollution and cause  
undesirable effects. When nitrates accumulate in water bodies, they can contribute to the process of  
eutrophication.  
Eutrophication occurs when an excessive amount of nutrients stimulates the growth of algae and other aquatic  
plants(Bhatnagar and Sillanpää, 2011). This excessive growth can lead to oxygen depletion in the water, harming  
fish and other aquatic organisms. Excessive levels of nitrates in water bodies can have significant consequences  
for human health as well. When consumed in drinking water, high levels of nitrates can be harmful, particularly  
for infants and pregnant women, as they can interfere with the ability of red blood cells to transport oxygen, high  
nitrate level in water may also cause cyanosis or the blue baby syndrome. Furthermore, certain bacteria can  
convert nitrates into nitrites, which are known to be potentially carcinogenic. Recognizing and managing the  
presence of nitrates in water is crucial for ensuring water quality and preserving the health of aquatic ecosystems.  
Monitoring nutrient levels, implementing agricultural best management practices, and using proper wastewater  
treatment processes are among the measures taken to mitigate the impacts of nitrates and phosphates in water  
(Boeykens et al., 2017). Phosphates are essential nutrients for animals and plants. They are commonly used in  
artificial fertilizers, phosphate-based detergents and are a byproduct of sewage treatment (Diaz-Uribe et al.,  
2025). Although they make up a valuable part of the eco-system, too many phosphates in our waters can cause  
problems and disrupt the delicate balance of animal and plant life. Phosphates end up in our water as run-off  
from agricultural sites and as part of the organic waste generated by sewage and industrial waste (Diaz-Uribe et  
al., 2025). Although plants need it to survive, too much speeds up eutrophication (which reduces the levels of  
dissolved oxygen in the water due to an increase in mineral levels).  
While certain levels of eutrophication happen naturally (such as lakes developing levels of sediment), there has  
been an increase in levels due to human behavior and this is having a detrimental impact on rivers, lakes and  
coastal areas (Boeykens et al., 2017). Excessive phosphorous in water can lead to algal blooms, green ‘clouds’  
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of algae. Although these aren’t dangerous in themselves, as bacteria break down dead algae, they consume  
oxygen (Daneshvar et al., 2018). This can create ‘dead spots’ in the water where aquatic life can’t survive due  
to a lack of oxygen. These algal blooms are a problem across the world, including the Lake District in England,  
Lyn Padarn in Wales and Forfar Loch in Scotland, which have all had to cancel water sport and swimming events  
due to high levels of algae in the water(Daneshvar et al., 2018)  
Adsorption with Nano sorbents such as the modified orange peel biochar is a very potent and adaptable technique  
for treating water. It may eliminate a variety of pollutants, frequently doing so completely. Furthermore, the  
quality of the treated water can be greatly enhanced by Nano sorbents, leaving it odour-free and transparent and  
ready for possible reuse applications. There exist diverse methodologies for the purification of water some of  
which are illustrated in Figure 1 below. There are biological and physico-chemical methods for reducing water  
contamination. Even though there are many different steps involved in treating water, not every method can be  
included in a single study. Thus, some of the important and pertinent methods have been highlighted in this  
chapter. These consist of membrane technologies, biological techniques, adsorption techniques, and flocculation  
and coagulation processes.  
Figure 1: Different kinds of treatment technologies for water treatment.  
The use of nanotechnology in water purification marks a dramatic advancement in environmental remediation  
that will have an effect on ecosystems and people alike. It is anticipated that the application of Nano adsorbents  
would open the door for new technologies, providing more effective means of preventing, detecting, and  
resolving different issues related to water pollution, such as wastewater treatment.  
Sources Of Water Contaminants  
Water pollution arises from either Point source pollution or Non-point source pollution. Point source pollution  
refers to contamination that comes from only one source. Examples include contamination from leaking septic  
systems, chemical and oil spills, illegal dumping, and wastewater (sometimes called effluent) released legally or  
illegally by a manufacturing, oil refinery, or wastewater treatment plant. By placing restrictions on what a facility  
is allowed to release into a body of water, the EPA controls pollution from point sources. Point source pollution  
can impact kilometres of streams and the ocean, even if it comes from a single location. Diffuse forms of  
contamination are considered nonpoint sources of pollution. These could include trash blown into waterways  
from the land or runoff from agriculture or storms. The primary source of water pollution in American waters is  
nonpoint source contamination, which is challenging to control because there isn't a single, obvious  
offender(Nalumenya et al., 2024)  
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Types Of Contaminants In Environmental Water  
Water contains a variety of different kinds of materials known as contaminants. Contaminants are substances  
that cause water to become unsafe when their concentrations exceed the advised limits. They pose a serious  
threat to all living things. Depending on their nature, these contaminants can be classified into several kinds (Qiu  
et al., 2022). They are often divided into four major categories (Figure 2).  
Figure 2: Types of various major contaminants in water  
Biological Contaminants: These include microorganisms like bacteria, viruses, parasites, and protozoa.  
Common examples are E. coli, Salmonella, and Giardia. They often originate from fecal matter and can  
cause diseases if ingested.  
Chemical Contaminants: These include a wide range of harmful substances, such as: Heavy Metals e.g  
Lead, mercury, arsenic for instance Arsenic is a major groundwater contaminant that has been linked to  
harmful health effects, including cancer. Groundwater contamination by heavy metals and radioactive  
elements is believed to affect more than 100 countries globally, with Asia having the highest prevalence  
of contamination, and cadmium, which can come from industrial activities, mining, and natural deposits;  
Pesticides and Herbicides. Industrial Chemicals Such as solvents, pharmaceuticals, and personal care  
products that may enter water through industrial discharges or improper disposal.  
Physical Contaminants: These include sediments, sand, and silt that can make water turbid and may carry  
other contaminants. They often result from erosion or runoff.  
Radioactive Contaminants: These include radionuclides like radon and uranium that can come from  
natural sources or nuclear activities. They pose health risks due to their radioactive properties. In naturally  
occurring groundwater, uranium is among the top three harmful pollutants, along with As and Cr (VI). It  
is a dangerous heavy metal and radioactive element that can harm human health when consumed in  
excessive quantities. Some of the negative effects include renal failure, reduced bone growth, and DNA  
damage (Girotto et al., 2024)  
Water Scarcity  
Water scarcity is attributed to water demand exceeding the available supply. It is a global issue, also in countries  
with sufficient water resources. This is attributed to various factors, such as poor infrastructure, and climate  
change. Some regions have seasonal variations while others have natural limited water resources that may cause  
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water scarcity. This leads to irregular supply of freshwater resources. Water management is essential for the  
world to achieve sustainable development (UNICEF, 1999). A country is said to experience water scarcity when  
the available natural water is below 1000m3 per capita (Kumari and Bhandari, 2022). One of the major water  
quality issues is water pollution, such as high levels of fluoride in water, which hinders the consumption of clean  
water. A great percentage of the world’s population, around 4 billion people, encounter extreme water scarcity  
no less than a month yearly with more than two billion people living in countries with inadequate water supply  
(Mulwa et al., 2021). According to statistics done by UNICEF, “Some 700 million people could be displaced by  
intense water scarcity by 2030.”  
Children and women are more prone to contaminated water. When more than 25% of renewable freshwater  
resources are withdrawn by a territory, the area is said to be “water-stressed”. Out of 11 regions, five experience  
water stress levels of over 25%. A UNICEF statistic shows that’ “1 in every 4 children globally will be living in  
areas of extremely high-water stress by 2040.” The global demand for water may exceed supply by over 40%  
by 2030 and over 50% in developing countries, mainly in sub Saharan Africa (Mekonnen and Hoekstra,  
2016).Population increase is one of the main factors that will lead to the reduction of per capita availability of  
drinking water. Socio-economic factors also facilitate water scarcity in various developing countries, limiting  
the provision of adequate sanitation services (Mulwa et al., 2021).  
People face diverse levels of water scarcity globally. Figure two displays the various levels, ranging from low  
to severe water scarcity, of the people facing water scarcity globally. The statistics ranges from 0 to twelve  
months. In one month, roughly 4.3 billion people experience moderate to worse water scarcity while 4 billion  
people severe water scarcity at least one month yearly (Mekonnen and Hoekstra, 2016).  
Table 1: Summary of the number of people experiencing different levels of water scarcity globally (Mekonnen  
and Hoekstra, 2016)  
India and China have the highest number of people living under severe water scarcity. This puts the country in  
a very vulnerable place. Among other countries experiencing severe water scarcity includes United States,  
Bangladesh, Pakistan, Mexico, and Nigeria.  
Kenya is among the water-stressed areas with per capita water availability under 1000m3 yearly (Lundberg,  
2025). Kenya relies on various water catchment sources that are unevenly distributed within the country  
(Lundberg, 2025). Factors such as geographical landscapes, population distribution, precipitation, and socio-  
economic activities, may lead to water scarcity.  
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Figure 2: Various water catchment areas in Kenya (Chepyegon & Kamiya, 2018)  
31.6% of Kenya’s total population utilize improper drinking-water origins, such as exposed dug wells. Moreover,  
about half of the total rural population utilize improper drinking-water sources (Yu et al., 2019).  
Water scarcity has various impacts such as poor hygiene and sanitation, which poses high health risks, especially  
in low-income areas, leading to contraction of various diseases. Shortage of water in Kenya is mainly observed  
in `arid, semi-arid, and rural areas. With water shortage in Kenya, children and women are required to travel  
long distances to search water, mainly for domestic use. Moreover, Kenya proper monetary, human, and  
institutional skills essential for provision of sufficient and clean water (Ondigo et al., 2018). Children, especially  
those living in areas with low-income, succumb to diarrhea due to consumption of unsafe drinking water (Mulwa  
et al., 2021).  
Health Effects Of Water Pollution.  
Contaminated water can carry pathogens such as bacteria, viruses, and parasites, leading to diseases like cholera,  
dysentery, hepatitis A, and typhoid fever. According to the World Health Organization (WHO), waterborne  
diseases account for a significant burden of illness worldwide, particularly in regions with inadequate sanitation  
and water treatment (Lo et al., 2022). Pollutants such as heavy metals (e.g., lead, mercury, arsenic) and industrial  
chemicals (e.g., pesticides, solvents) can contaminate drinking water. Long-term exposure to these substances is  
associated with various health issues, including cancer, neurological damage, and developmental problems in  
children. For example, arsenic contamination is linked to an increased risk of skin cancer and other malignancies  
(Smith et al., 2002). Chemicals like endocrine-disrupting compounds (EDCs), which can be found in polluted  
water, may interfere with hormonal systems. This disruption can lead to reproductive health problems,  
developmental issues, and other endocrine-related disorders. Research has shown that EDCs can affect both  
aquatic and human life, leading to developmental and health problems (Colborn et al., 1993). Water pollution  
can impact food security by affecting the quality of water used for irrigation, which in turn can impact crop yield  
and nutritional value. Polluted water can also lead to contamination of aquatic food sources, potentially leading  
to deficiencies in essential nutrients and vitamins (Cairncross et al., 2010). There is emerging evidence  
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suggesting that exposure to polluted water can have indirect effects on mental health. The stress and anxiety  
associated with health concerns and the degradation of environmental quality can impact mental well-being.  
Studies have found associations between environmental stressors and mental health outcomes, highlighting the  
need for more research in this area.  
Figure 4: Major health effects due to water pollution  
Chemical Composition and Physical Properties of Orange Peel  
The chemical composition of orange peel differs based on location, varieties, level of maturity, and growing  
conditions. According to Mafra (Mafra et al., 2013). orange peel is 97.83% organic matter and contains carbon,  
hydrogen, oxygen, nitrogen, sulphur, chloride, and ash. Bampidis further confirmed the organic matter  
composition of orange peel, reporting that the dry matter of orange peel is mainly organic matter containing  
proteins and short-chain organic acids no more than four carbons. Others opined that orange peel contains soluble  
sugar, starch, and fiber, including cellulose, hemicellulose, lignin, and pectin, as well as ash, fat, protein, and  
about 1% organic acids.  
In addition, several studies on the physical properties of orange peel have revealed that it contains cellulose,  
hemicellulose, lignin, and pectin. Cellulose is the most abundant polysaccharide found in the cell walls of plant  
biomass (Al-Harahsheh et al., 2014). The chemical formula of cellulose is (C HO) n, where n represents the  
number of glucose groups, ranging from hundreds to thousands. Cellulose is insoluble in water, dilute acid, and  
dilute alkali solutions, and is recalcitrant to hydrolyses and enzymatic activities due to their strong hydrogen  
bonds; the chemical structure of cellulose is presented in Figure 5.  
Figure 5: Structure of cellulose.  
Unlike cellulose, hemicellulose has a random, amorphous structure composed of various sugar monomers, which  
have little physical and chemical resistance, and their polymerization degree is between 50–200 °C.  
Hemicelluloses are mostly soluble in water and dilute in alkali solutions at temperatures above 180 °C, but they  
are insoluble in water at temperatures below 180 °C and account for about one third of total biomass weight  
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(Saranyadevi et al., 2023). Together with cellulose and hemi-cellulose, lignin is found in the cell walls of plants;  
it is the second most abundant compound of plant biomass with a complex hydrocarbon polymer that consists  
of both aliphatic and aromatic compounds. The basic monomeric units of lignin are P-hydroxyphenyl, guaiacyl,  
and syringyl. Lignin is hydrophobic in nature, totally insoluble in most solvents, and is thermally stable but prone  
to UV degradation. Pectin is a complex polysaccharide found in the cell walls of plants and contributes to the  
firmness and structure of plant tissues. They are composed of 1,4 α-D-galacturonic acid (GA) in free or esterified  
form. The basic monomer of pectin includes rhamnose, galactose, arabinose, glucose, and xylose (Wang et al.,  
2022)  
Preparation and modification of orange peel biochar.  
Orange peel, or OP as it is now commonly called, is a cheap, plentiful, and easily accessible biomass waste from  
the orange juice manufacturing industry. OP is mostly composed of low molecular weight substances (such as  
limonene), cellulose, hemicellulose, lignin, pectin, and chlorophyll pigments. Considerable environmental harm  
could result from improper disposal of this biomass. Its therefore considered as a green alternative to preparation  
of biochars for environmental remediation such water purification. Biochar is a carbon-rich and stable carbon  
dominant product that may formed through pyrolysis in an oxygen deficient reactor chamber. It has the potential  
of carbon sequestration, soil enhancement and waste management (Otieno et al., 2024).The orange peels were  
collected, cleaned and crushed into a fine powder after which the biochar was prepared according to the  
specifications of (Liu et al., 2023) with some modifications of using Aluminum tri-chloride to enhance the  
surface porosity and increase the selectivity to the contaminants.  
FIG 6:Orange peels cuttings.  
FIG 7: Preparation of modified orange peel biochar (MOPB)  
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Various Approaches To The Application Of Modified Orange Peel Biochar(Mopb)  
Conventional water treatment methods often fall short of removing these contaminants. By their very nature,  
industrial effluents are complex mixtures of diverse pollutants with varying chemical properties, making them  
particularly challenging to treat (Sathya et al., 2022).To effectively address this issue, a multi-pronged approach  
combining techniques like extraction, filtration, biological treatment, physicochemical methods, sorption, and  
catalytic oxidation is necessary to transform these effluents from highly contaminated streams to ones that meet  
discharge standards. Among these techniques, sorption techniques play a crucial role in wastewater treatment by  
removing contaminants through adsorption and absorption processes. Adsorption involves the accumulation of  
molecules at the liquid-solid interface, with act MOPB being a widely used adsorbent due to its high surface  
area and effectiveness in removing organic pollutants (El Gheriany et al., 2020). On the other hand, absorption  
entails the dissolution and diffusion of substances throughout another material, as seen in using granular  
activated carbon (GAC) to eliminate taste and odor compounds from drinking water (Hardyanti et al., 2023).  
These methods are essential for reducing pollutants in water sources.  
The process of sorption is essential for eliminating contaminants from water systems. The sorption process is  
influenced by multiple mechanisms, including hydrogen bonding, hydrophobic interactions, and electrostatic  
interactions (Vujić et al., 2023). For many organic contaminants, hydrophobic interactions predominate, drawing  
non-polar molecules to the sorbent's carbon-rich surface. Generated as a result of shared oxygen and hydrogen  
atoms between the sorbent and the contaminant. The characteristics of the contaminant determine how successful  
these systems are. sorbent, along with the pH and ionic strength of the water matrix. Recognizing these  
mechanisms is necessary to create effective pollution removal techniques and optimize adsorbents methods of  
elimination. In wastewater treatment, sorption is influenced by a number of important factors. The effectiveness  
of pollution removal is affected by the starting concentration of the pollutant; larger concentrations accelerate  
clearance until saturation. The sorption capacity is determined by the sorbent properties, such as surface area,  
pore size distribution, and surface chemistry. pH values in wastewater has an impact on sorbents and  
contaminants' charges, which influences electrostatic correspondences (Jagadeesh and Sundaram, 2023). There  
is a role for temperature and sorption. Temperature increases usually result in a loss in efficiency. Furthermore,  
the existence of dissolved ions or organic debris, among other competing substances, can obstruct the sorption  
process by vying for available sorption spots  
Adsorption Properties of Modified Orange Peel biochar (MOPB).  
Rich in Functional Groups: MOPB contain a variety of functional groups, such as hydroxyl, carbonyl, and  
carboxyl groups. These functional groups are capable of forming chemical bonds with nitrates and phosphates  
through ion and exchange, electrostatic attraction, hydrogen bonding, and coordination, facilitating the  
biosorption process (Mafra et al., 2013). The components of orange peel, including cellulose, hemicellulose,  
lignin, and pectin, are the reason for the smooth surface structure. Smooth surfaces have low adsorption uptake  
due to the reduced number of active sites available for the adsorption of contaminants, and do not allow  
significant binding of contaminants, hence the reason for the low biosorption uptake of orange peel (El Gheriany  
et al., 2020). High Surface Area: MOPB have a porous structure, providing a large surface area for interaction  
with nitrates. This increased surface area allows for more contact points, enhancing the adsorption capacity and  
efficiency of nitrate removal (Singh et al., 2017). Roughness and porosity are usually linked to the high sorption  
capacities of biomass because they provide more active sites for adsorption than smooth surfaces. However,  
studies have shown that the adsorption capacities of a biomass can be improved by increasing the surface  
roughness and porosity using different modification methods, including physical, chemical, and thermal  
methods. Hence, the aim of the modification process is to improve the structural properties of the biomass,  
resulting in an increased binding site and biosorption uptake of the biomass. Negatively Charged Surface: The  
surface of MOPB is typically negatively charged. This negative charge can attract and bind positively charged  
nitrate ions through electrostatic interactions, enhancing the biosorption efficiency and affinity for  
nitrates(Bhatnagar and Sillanpää, 2011).It is observed that the removal efficiency of modified orange peel  
biochar for nitrate and phosphate ions provides critical insight into its suitability as a sustainable biosorbent for  
nutrient remediation. In this study, modified orange peel biochar achieved an optimum removal of 89% nitrate  
removal and 85% phosphate removal under optimized conditions as presented in Figure 8, demonstrating strong  
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affinity for both anionic contaminants. These efficiencies fall within the upper range reported for biochar-based  
sorbents and significantly outperform many unmodified agricultural wastes  
Figure 8: Phosphate removal efficiency (A) and Nitrate removal efficiency (B)  
Summary on parameters affecting Adsorption Process  
Adsorption process can be affected by several factors that need optimization to maximize the adsorption capacity  
and adsorbate removal.  
Effects of Temperature  
Le Chatelier’s principle explains that adsorption is an exothermic (Pandey et al., 2010). Effects of temperature  
on adsorption process is due to the bonds formed and properties of the adsorbents and adsorbate sites. Adsorption  
increases at low temperature as a result of strong bonds. However, when the adsorbent’s temperature is high,  
desorption occurs and the adsorbate molecules are withdrawn due to weak bonds. This shows that an increase in  
temperature leads to a decrease in the adsorption process.  
Effects of Dosage  
To calculate the adsorption capacity, the mass of the removed adsorbate is evaluated per the adsorbent mass.  
The adsorption rate increases with an increase in the adsorbent dosage, which increases the sorption sites on the  
adsorbent’s surface. The effects of dosage are done through preparation of various mass of the adsorbent to a  
fixed adsorbate concentration(Otieno et al., 2024).  
Effects of Adsorbent size  
The rate of adsorption increases due to a larger surface area. Moreover, a small particle diameter and size, caused  
by mass transfer and internal diffusion, leads to the penetration restraint of the adsorbate to the adsorbent. This  
makes equilibrium be attained more quickly, increasing the adsorption capacity.  
Effects of PH  
PH is a critical parameter since it controls the level of electrostatic charges from ionized adsorbates. It also  
governs the fluoride concentration mobility in groundwater. The adsorption rate varies with medium PH but not  
in a regular pattern. However, the adsorption capacity of cations and anions decreases and increases respectively  
at low PH values(Chowdhury and Balasubramanian, 2014). When the PH increases, the electrostatic repulsion  
of the adsorbent and adsorbate cations decreases leading to an increase in the surface’s charge density.  
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Effects of Contact time  
Adsorption performance is affected by the contact time between the adsorbate and adsorbent. The adsorption  
capacity tends to increase with an increase in contact time to a certain point. After that, saturation hinders an  
increase in adsorbate intake caused by increased contact time. The equilibrium time establishes the amount of  
adsorbate removed or adsorbed from the adsorbent. The maximum adsorption capacity is represented by the  
amount of adsorbate adsorbed.  
Effects of Initial Concentration  
An increase in initial concentration of the adsorbate leads to an increase in the overall removal and a decrease in  
adsorption capacity. To determine the effect of initial concentrations, an adsorbate solution is prepared at varying  
concentrations under a constant temperature, contact time, and ph. This will help study and understand the  
relation between the adsorbent and adsorbate, using isotherm models.  
The use of MOPB Nano sorbents in adsorption is a particularly potent and adaptable technique for treating water.  
It may eliminate a variety of pollutants, frequently doing so completely. Furthermore, the quality of the treated  
water can be greatly enhanced by Nano sorbents, leaving it odour-free and transparent and ideal for possible  
reuse applications (Muhammad et al., 2016).  
Biosorption capabilities of modified orange peels biochar (MOPB).  
Biosorption is a type of physiochemical process, which uses biological materials to bind over the contaminants  
onto its cellular structure. The use of biomass in environmental cleanup especially in environmental waste waters  
has been in practice for a while, and scientists and engineers are hoping this phenomenon will provide an  
economical alternative for removing toxic heavy metals, disastrous ions like nitrates, phosphates and fluorides  
from industrial wastewater and aid in environmental remediation (Al-Harahsheh et al., 2014). It is proven a cost-  
effective method for the removal of various ions in the water (Angelova et al., 2011).  
Most studies indicate that orange peels are used as effective bio sorbents for the removal of nitrates and  
Phosphates in the water. The orange peel biochars have maximum removal efficiency of ammonia and nitrates  
at a concentration of 4gm. The optimum biosorption of ammonia and nitrate over MOPB bio sorbent was  
obtained at pH = 5.5, contact time = 60 min, and temperature= 35 °C (Angelova et al., 2011). Recent studies  
indicated that the use of synthesized environmental waste materials for the removal of excess chemical  
constituents in the water became popular because of economy factor. Various researchers worked on the removal  
of nitrates by using environmental waste bio sorbents like Bael leaves (Aegle marmelos), Mausmi peel powder,  
Green algal powder, Barks and stems of annoma squamosal, banana peels and Greenish clay rich in free silica  
etc. The removal efficiencies varied from one material to another depending upon their pH, contact time,  
adsorbent dosage, time of equilibration, initial concentrations and temperature ranges.  
Qualities of Optimal Bio sorbent Substance.  
The contact angle (CA) is a direct representation of surface wettability. Super-bio sorbents, as defined by  
(Srinivasulu, 2023)are rough surfaces that have a small contact angle hysteresis value and a high-water contact  
angle of ≥150°.Surface roughness amplifies a material's hydrophobic and oleophilic properties, supporting  
Wenzel's wettability theory that the contact angle rises with porosity and material surface roughness. Plants with  
naturally occurring superhydrophobic surfaces, such lotus leaves, cotton fibers, and kapok fibers, have high  
water contact angles. Lotus leaves have a structure made up of a combination of two scale roughness levels of  
10 μm (rough), with a water contact angle (CA) of 161°.  
The hydrophobic nature of lotus leaves arises from a combination of the epicuticular wax secreted from the leaf  
itself and the roughness. Kapok fibre has a water contact angle (CA) that ranges from 138.6° to 151.2° depending  
on the location, making it a superhydrophobic surface (Dong and McCarthy, 2017). Some researchers have  
reported that kapok fibre is mainly composed of cellulose, lignin, and pentosan, while others have opined that  
kapok fibres comprises of cellulose, lignin, xylene, and high levels of acetyl groups. Kapok fibres possess waxy  
coatings and a large hollow structure that gives it a porosity of 80%, which is responsible for the hydrophobic  
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INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN APPLIED SCIENCE (IJRIAS)  
ISSN No. 2454-6194 | DOI: 10.51584/IJRIAS |Volume X Issue XI November 2025  
nature of kapok leaves. According to studies, the water contact angle of cotton fiber is 100°, cotton fibres is  
about 90% cellulose, and the non-cellulose part includes proteins, waxes, pectin, inorganics, and other  
substances; however, the composition of cotton fibres differs based on location and maturity  
Future Prospects For Modified Orange Peel Biochars.  
Modified Orange peel biochar has a promising future prospect due to several factors: For instance; It can enhance  
soil fertility by improving soil structure, increasing water retention, and providing essential nutrients. Its use in  
agriculture could help in sustainable farming practices. Utilizing modified orange peels, a common agricultural  
and food waste, for biochar production helps in waste reduction and resource efficiency. Biochars sequester  
carbon, potentially mitigating climate change by reducing the amount of CO2 released into the atmosphere and  
this is helpful in mitigating the global warming due to creation of the ozone hole. Modified Orange peel biochar  
(MOPB) has shown potential in adsorbing contaminants from water and soil, aiding in environmental cleanup  
efforts. And as technology advances and production scales up, the cost of producing biochar may decrease,  
making it a more attractive option for various applications. Therefore, research and development are likely to  
continue focusing on optimizing the production process, modification for better selectivity and sensitivity and  
expanding applications to fully realize these benefits.  
CONCLUSION  
In conclusion, modified orange peel biochar represents a sustainable and multifunctional material with  
significant potential. From an environmental perspective, biochar contributes to carbon sequestration, helping to  
mitigate climate change by capturing and storing carbon. Its application in pollution remediation further  
underscores its versatility, as it can adsorb contaminants from soil and water, aiding in environmental cleanup  
efforts. As research advances and production techniques become more efficient, the economic feasibility of  
orange peel biochar is expected to improve, potentially leading to wider adoption. The growing interest in  
sustainable practices and circular economy principles will likely drive further exploration of its applications and  
benefits. MOPBs could become a key component in sustainable practices, offering ecological and economic  
advantages. Modified orange peel biochar therefore holds considerable promise for enhancing soil health,  
managing waste, and addressing environmental issues, making it a valuable asset in the pursuit of sustainability  
and resource efficiency.  
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