Crude Oil Remediation Research Articles

Phytoremediation of Crude Oil Polluted Soil Using Dried Yam Peels (Discorea sp) as a Case Study in Niger Delta Environment of Southern Nigeria

This study aimed at enhancing the remediation of crude oil polluted soil using yam peels. 2kg of the soil samples were polluted crude oil at different concentrations ranging from 5%, 10% and 15%. There were three amended and un-amended samples each labeled A-F. The amended samples were A, C and E which contained the following respectively, 5% polluted soil + 150g yam peels, 10% polluted soil + 150g of yam peels and 15% polluted soil + 150g yam peels. The un-amended samples were B, D and F which were called the control samples with 5%, 10% and 15% concentration of crude pollutant. Parameters such as soil moisture content, total organic carbon, pH and total hydrocarbon content were analyzed before and after remediation. The result showed that yam peels enhanced remediation of the soil especially in treatment A. The reduction in Total Hydrocarbon Content was highest in the 5% crude oil polluted soil sample resulting 57.4% and least at 15% polluted control sample resulting 44.2%. The higher the concentration of crude oil in the soil the lower the percentage degraded. Yam peels which are agro waste can enhance biodegradation of crude oil in polluted soil and therefore can act as remediating agent.

Scalable fabrication of efficient and recycling wood residue-derived sponge for crude oil adsorption

Fast, low-cost, and efficient technology for crude oil remediation is a challenge. Herein, we reported a wood residue-derived sponge immobilized with Fe 3 O 4 nanoparticles (NPs) via the delignification, high-speed dispersion and freeze-drying processes, which allows fast and efficient cleanup of crude oil spill with the assistance of solar irradiation. Magnetic wood residue-derived sponge (M-sponge) with uniformly distributed Fe 3 O 4 NPs exhibits excellent photothermal conversion effect and can adsorb 172.62 g g -1 of crude oil in the first 15 minutes. Meanwhile, the M-sponge with good magnetic property is easily recycled by an external magnet and keeps high crude oil uptake of 154 g g -1 at least 10 adsorption-desorption cycles. Combining with the light weight (9 g m -3 , porosity > 91%), none harmfully hydrophobic chemicals, synthesis simplicity, and abundant starting materials, M-sponge design represents a high-value utilization based on forestry waste in the field of crude-oil remediation and water treatment. • A solar-assisted self-heating magnetic sponge adsorbent is constructed. • M-sponge with high photothermal conversion efficiency exhibits the adsorption capacity up to 172.62 g g -1 for crude oil. • M-sponge can be recovered by magnet and shows adsorption attenuation less than 11% after 10 times recycling. • Without toxic chemical reagents addition, the raw materials are sustainable, abundant and low-cost.

Kinetics of Bioremediation of Oil Contaminated Water Dispersed by Environment-Friendly Bacteria (<i>Pseudomonas aeruginosa</i>) and Fungi (<i>Aspergillus niger</i>)

The comparative effectiveness of remediating water polluted with crude oil, using environment-friendly bacteria (Pseudomonas aeruginosa) and fungi (Aspergillus niger) were investigated. The samples were separately treated with Aspergillus niger and Pseudomonas aeruginosa. The bioremediation kinetic efficiency for these systems was studied. At the end of the bioremediation periods, the oil and grease content of the samples decreased from 47.0 mg/L in the untreated sample to 7.0 mg/L after 20 days when inoculated with bacteria while the sample inoculated with fungi decreased to 10.0 mg/L. Post analysis when inoculated with bacteria showed a fall in the value of the biological oxygen demand (BOD) from 73.84 mg/L to 33.28 mg/L after 20 days, while, the fungi inoculated sample showed a reduction from 73.84 mg/L to 38.48 mg/L. The biodegradation process with the bacteria was consistent with the pseudo-first-order model with a rate constant of 0.0891 day-1, while the biodegradation process with the fungi was consistent with the first order reaction model with a rate constant of 0.422 day-1. The degree of degradation after the 20th day of inoculation with Pseudomonas aeruginosa was 85.11%, while with Aspergillus niger was 78.72%. Thus, the results obtained showed that, Pseudomonas aeruginosa performed better than Aspergillus niger. The bioremediation data with fungi fitted the first-order model, while that of the bacteria fitted the pseudo-first-order model. Therefore, the data obtained in this study could be applied in the design of a bioremediation system for potential application to remediation of crude oil polluted water.

Hydrated manganese hydrogen phosphate coated membrane with excellent anticrude oil-fouling property for separating crude oil from diverse wastewater

The development of oil-resistant materials to eliminate spilled viscous crude oil remains a challenge. Herein, a self-cleaning (anticrude oil-fouling) coating composed of hydrated manganese hydrogen phosphate (MnHPO4·3H2O, MHP) is reported. The anticrude oil-fouling property is well correlated with MHP having abundant surface hydrogen phosphate groups. The coating exhibits exceptional binding affinity for water even when fouled by crude oil. Due to the antioil-fouling properties of the MHP coating, copper mesh coated with MHP can separate highly viscous crude oil/water mixtures and crude oil-in-water emulsions before being prewetted with water and can remove floating crude oil from oily wastewater without being prewetted with water, which brings promising for practical applications in spilled crude oil remediation.

Isolation of Biosurfactant-Producing Bacteria and Their Co-Culture Application in Microbial Fuel Cell for Simultaneous Hydrocarbon Degradation and Power Generation

Biosurfactant-producing microorganisms improve the efficacy of hydrocarbon biodegradation as the biosurfactant is essential in making hydrocarbons available for breakdown. The present study reports the isolation of biosurfactant-producing bacteria that can be used for crude oil remediation and to characterize the biosurfactant generated during the breakdown of crude oil. This study also reports evaluating the synergism and potentiality of biosurfactant-producing bacteria for simultaneous hydrocarbon biodegradation and power generation. Two bacterial strains (Bacillus subtilis strain B1 and Pseudomonas aeruginosa strain B2) were isolated from petroleum-contaminated soils, which are found effective in producing biosurfactants and degrading crude oil as the sole carbon source. B. subtilis B1 exhibited a higher potential for biosurfactant production and crude oil degradation than P. aeruginosa B2. The FTIR and GC-MS analysis were conducted for further characterization of the biosurfactant, which revealed that the surfactant produced by strain B1 and B2 was surfactin and rhamnolipid, respectively. The application of the B1 and B2 co-culture in microbial fuel cells (MFCs) showed synergism among them and resulted in a maximum power density production of 6.3 W/m3 with an open circuit voltage of 970 mV while degrading 2.5% v/v crude oil containing anolyte. The findings indicate that the co-culture of isolated crude oil-degrading strains has great potential for enhanced power generation and the bioremediation of hydrocarbon-contaminated environments. Moreover, the synergism of isolated strains in MFCs suggested their potent applicability in environmental, energy, and industrial sectors as an economical and feasible alternative to the existing technologies.

Microbial Remediation of Crude Oil in Saline Conditions by Oil-Degrading Bacterium Priestia megaterium FDU301.

Salinity greatly affects the microbial degradation process of crude oil; thus, the isolation and identification of halotolerant microbes is essential. Limited studies explored how microbes respond to increased salinity. In this study, an oil-degrading bacterium Priestia megaterium FDU301 was isolated from the Dagang oil field, which can tolerate a salinity of 6%. Compared to the non-saline condition, oil degradation ratios by P. megaterium FDU301 increased by 15.27% and 11.26% in 0.5% and 3.5% salinity media, respectively. Meanwhile, bacteria degraded various components of crude oil more thoroughly in saline environments, especially mid-chain hydrocarbons (C11-C18). Surface tension under salt stress was lower than that in the non-saline medium, indicating that the amount of biosurfactants produced by bacteria was increased. The microbial activity enhanced markedly in response to increased salinity, which was the main factor for the high degradation ability. As a vital component of biofilms, the production of polysaccharides was accelerated with P. megaterium FDU301 inoculation in saline environments. These results indicate that P. megaterium FDU301 has great potential application in oil bioremediation in saline environments.

Evaluation of biosurfactant production by Sporosarcina halophila and its application in crude oil remediation

Background: Biosurfactants are valuable microbial products that have significant applications in various industries. The advantages of these compounds are biodegradability, low toxicity, activity in difficult environmental conditions, and the ability to produce oil residues and compounds from the surface of seawater and soils contaminated with oil compounds. The aim of this study was to evaluate the ability of biosurfactants production by Sporosarcina halophila. Methods: For this purpose, to detect the production of biosurfactant by Sporosarcina halophila, quantitative and qualitative screening methods such as hemolysis, oil spreading test and emulsification index test were used. Finally, different concentrations of crude oil in the bacterial growth medium were used to see that this strain can decompose crude oil using biosurfactant production to continue its growth or not. Results: The results showed that this strain is able to produce biosurfactants in oil hemolysis and spreading test with emulsifying activity of more than 30%, indicating that this strain is a suitable strain for biosurfactant production. Also, this strain could grow in the presence of crude oil in its medium as only carbon resource by biosurfactant production. Conclusion: This study showed that the metabolites derived from Sporosarcina halophila strain have emulsifying properties and can be considered as a potent strain in the production of biosurfactants. Also, it was concluded that these biosurfactants are applicable for many different industrial or environmental fields such as bioremediation of crude oil from soil or water by Sporosarcina halophila strain.

Kinetic modeling and half-life study on bioremediation of crude oil dispersed by palm bunch enhanced stimulant

The work focused on the kinetic modeling and half-life study of the bioremediation of crude oil dispersed by palm bunch enhanced stimulant. In this study, three bioremediation processes, namely; palm bunch enhanced stimulant (PES) stimulation, modified crude oil dispersant (MCD) stimulation and natural attenuated stimulation (NAS), were carried out at various petroleum hydrocarbon concentrations in polluted water media. Bacterial culture, isolations, and identification were carried out to isolate and identify the bacterial involved in the bioremediation. The process kinetics and half-life were investigated. Characterization of PES showed that PES has an appreciable quantity of potassium, phosphate, nitrate, sulphate and calcium required for cell growth and development. Bacillus pumilus, Micrococcus roseus, Micrococcus luteus, and Pseudomonas putida were the bacteria isolated from the culture. The optimum bio-stimulation efficiency of PES occurred on day 6, with BE values of 93.23%. The degradation rate constants for the PES enhanced bioremediation process decreased as the crude oil initial concentration increased from 100 to 300 mg/L. The result showed that the degradation rate constants for PES stimulated remediation were 0.11, 0.04 and 0.03 at 100, 200 and 300 mg/L of crude oil, respectively. The MCD stimulated remediation showed degradation rate constants of 0.04, 0.03 and 0.018, at crude oil concentrations of 100, 200, and 300 mg/L, respectively. The trend was the same for NAS. The longest half-life for 100 mg/L of crude oil was achieved after 79.67 days during the NAS stimulation. The results obtained from this report showed tremendous improvement to the degradation of crude oil due to the presence of PES. The degradation process was adequately described by the first order kinetic model and showed the effectiveness of PES in the remediation process. Therefore, the data obtained in this study could be applied in the design of a bioremediation system for potential application to remediation of crude oil polluted water.

Computer-aided Degradation Susceptibility Study of Crude Oil Compounds at Bacillus subtilis Protein Target

Certain bacteria and fungi have been associated with the oxidative degradation of hydrocarbons and hydrocarbon derivatives in soil and water contaminated by crude oil spilling in these ecosystems. The binding affinity of hydrocarbons and hydrocarbon derivatives in a crude oil sample on the cysteine dioxygenase of Bacillus subtilis was studied using computational methods. The study was aimed to validate the claim of the efficient use of this organism in crude oil remediation and to determine the selectivity of the compounds in the crude by this bacterium enzyme. The compounds in the studied crude oil sample were identified by gas chromatography-mass spectrometry. Straight chain hydrocarbons were the least selected class of compounds with binding free energy ranging between –2.9 kcal/mol to –3.1 kcal/mol. The straight-chain hydrocarbon derivatives containing carbonyl and hydroxyl groups formed the middle class of compounds selected by the enzyme with binding free energy ranging between – 3.3 kcal/mol to –3.7 kcal/mol. The best binding free energies (–3.8 kcal/mol to –5.1 kcal/mol) were obtained with the poly-branched hydrocarbons and the cyclic compounds. The amounts of the poly-branched and cyclic compounds in the crude oil sample suggested that cysteine dioxygenase of B. subtilis would show about 28 % efficiency in the bioremediation of environments polluted by crude oil of this composition.

The Effect of Remediation of Crude Oil Contaminated Land on Agricultural Resources in Umuechem in Etche Local Government Area of Rivers State, Nigeria

Contamination is the release of hazardous materials into the environment; which could be in the form of: waste, petroleum hydrocarbons and other unwanted materials. The release of these hazardous materials could affect soil nutrients and aggravate biodiversity loss. When the soil nutrient is impacted, it negatively affects its crop yield and production capabilities. Once there is contamination of the environment, remediation becomes necessary. This paper examines the effects of remediation of crude oil contaminated land on agricultural resources in Umuechem in Etche Local Government Area of Rivers State, Nigeria. Purposive sampling technique and a survey research design was adopted with the use of structured questionnaires administered on a sample size of sixty two (62) persons whose farmlands and other agricultural resources were contaminated and thereafter remediated. The sample size was made up of fifty four (54) literate and eight (8) illiterate persons. The questionnaire was interpreted in native language to the illiterate persons by either their children or any other relative. The data obtained from the survey were analysed using descriptive statistics such as tables and statistical package for social sciences (SPSS).The findings obtained indicated that there was a post-remediation low-crop-yield and recommended that remediation consultants should adopt techniques capable of completely removing contaminants from the environment.

Remediation of Crude Oil Contaminated Soil with a Low Temperature Oxidation Enhanced Thermal Desorption Process

Remediation of Crude Oil Contaminated Soil with a Low Temperature Oxidation Enhanced Thermal Desorption Process

Insight into Remediation of Crude Oil Contaminated Soil in Rivers State Nigeria: Obstacles and Options (2012-2022)

Insight into Remediation of Crude Oil Contaminated Soil in Rivers State Nigeria: Obstacles and Options (2012-2022)

Bioaugmentation-Enhanced Remediation of Crude Oil Polluted Water in Pilot-Scale Floating Treatment Wetlands

Floating treatment wetlands (FTWs) are cost-effective systems for the remediation of polluted water. In FTWs, the metabolic activity of microorganisms associated with plants is fundamental to treatment efficiency. Bioaugmentation, the addition of microorganisms with pollutant-degrading capabilities, appears to be a promising means to enhance the treatment efficiency of FTWs. Here, we quantified the effect of bioaugmentation with a four-membered bacterial consortium on the remediation of water contaminated with crude oil in pilot-scale FTWs planted with Phragmites australis or Typha domingensis. The bacteria had been isolated from the endosphere and rhizosphere of various plants and carry the alkane hydroxylase gene, alkB, involved in aerobic hydrocarbon degradation. During a treatment period of 36 days, FTWs planted with P. australis achieved a reduction in hydrocarbon concentration from 300 mg/L to 16 mg/L with and 56 mg/L without bioaugmentation. In the FTWs planted with T. domingensis, respective hydrocarbon concentrations were 46 mg/L and 84 mg/L. The inoculated bacteria proliferated in the rhizoplane and in the plant interior. Copy numbers of the alkB gene and its mRNA increased over time in plant-associated samples, suggesting increased bacterial hydrocarbon degradation. The results show that bioaugmentation improved the treatment of oil-contaminated water in FTWs by at least a factor of two, indicating that the performance of full-scale systems can be improved at only small costs.

Development of an adsorbent for the remediation of crude oil polluted water using stearic acid grafted coconut husk (Cocos nucifera) composite

With increasing crude oil contamination scenes reported around the globe, highly promising materials are important to remove crude oil from water bodies for safeguarding the public health, aquatic life and sustaining agricultural activities. In this work, we have prepared agro-based material (Cocos nucifera husk) composite with high surface area and well-ordered framework of porosity for crude oil removal. Material characterization was carried out to expose the nature of the composite prepared and its affinity to oil sorption. Adsorption studies were evaluated in batch mode with the function of oil-water ratio, temperature, time and pH as well as reuse with suitable eluent. High adsorption efficiency was exhibited by the composite at low pH as the surfaces were predominantly positive at 0.05 mol/dm3 and 0.10 mol/dm3. Differential thermo gravimetric analysis (DTA) revealed that esterified coconut husk (CHs) was thermally stable at 432.7 °C. In addition, the composite demonstrated good potential as adsorbent with 96.4% crude oil removal after 50 mins at 0.2 g/100cm3. The adsorption isotherm data were well fitted to the Langmuir isotherm model as expected from the structural homogeneity of the conjugated material with maximum adsorption capacity of 69.86 mg/g. The experimental kinetic data were adequately matched by pseudo-second order kinetic model (R2≥ 0.99). Crude oil was eluted from the composite with ethanol and regenerated to the original pattern. The regenerated material exhibited the same functionality and was used successively in several adsorption -elution-reuse-cycle. Therefore, the newly developed composite material is an interesting, efficient and economic sustainable material.

Preparation and Characterization of activated carbon from agricultural waste (Musa-paradisiaca peels) for the remediation of crude oil contaminated water

In this work, acetylated plantain peels as a novel composite with high surface area and well-ordered framework of porosity was prepared. Kinetic and isotherm modelling of crude oil removal was considered as well. Batch adsorption studies were carried out with the function of oil water ratio, pH and temperature. Characterization of activated carbon was carried out to ascertain the nature of the composite prepared and its affinity to oil sorption. Surface morphology was investigated with scan electron microscope (SEM). Chemical composition of compounds was investigated using X-ray fluorescent machine while the X-ray diffraction machine (XRD) examined the crystallographic nature of the plantain peels. Salt addition techniques was employed for point zero charge analysis at ionic strengths 0.05 and 0.1 mol/dm3. The influence of pH, temperature and oil/water ratio was found to be highly significant and strongly influenced oil removal by the composite. SEM analysis showed several changes on the surface of the composite after acid treatment. XRF and XRD revealed that the raw plantain peels were highly composed of quartz. The point zero charge revealed that the surface of acetylated plantain peels was predominately positive charge at pH ranging between 4.05±0.1 and 4.07±0.1. However, the composite exhibited high adsorption efficiency at a very low pH of 5 with 90.9% of crude oil removal. Isotherm modelling revealed that the composite material was highly matched to Temkin isotherm model with maximum adsorption capacity of 50.1mg/g. The kinetic data fitted well with Bahattacharya-Venkobachor model. The regenerated biomass exhibited high performance and functionality and used successively in different adsorption activities. Therefore, acetylated plantain peel composite is an efficient, economic viable and sustainable adsorbent materials suitable in remediation of crude oil polluted water.

Integration of biosorption and biodegradation in a fed-batch mode for the enhanced crude oil remediation.

Microbial bioremediation of oil-contaminated sites is still a challenge due to the slower rate and susceptibility of microbes to a higher concentration of oil. The poor bioavailability, hydrophobicity, and non-polar nature of oil slow down microbial biodegradation. In this study, biodegradation of crude oil is performed in fed-batch mode using an oil-degrader Pseudomonas aeruginosa to address the issue of substrate toxicity. The slower biodegradation was integrated with faster biosorption for effective oil remediation. Highly fibrous and porous sugarcane bagasse was surface modified with hydrophobic octyl groups to improve the surface-oil interactions. The microbe showed 2 folds enhanced oil degradation in the fed-batch study, which was further increased by 1·5 folds in the integrated biosorption coupled biodegradation approach. The biosorption-assisted biodegradation approach supported the microbial growth to 2 folds higher than the fed-batch study without biosorbent. The analysis of biosurfactant production indicated the 3 folds higher concentration in fed-batch modes as compared to batch study. In the integrated strategy, the concentration of contaminant (oil) reduces to quite a tolerable level to microbes, which improved effective metabolism and thus overall biodegradation. This study puts forward a promising strategy for improved degradation of hazardous hydrophobic contaminants in a sustainable, economic and eco-friendly manner.

Capability of Vetiver (Vetiveria Zizanioides), Guinea Grass (Panicum Maximum) and Organic Manures to Remove Total Hydrocarbon and Heavy Metals from Crude Oil Contaminated Soil in Port Harcourt

In a field study conducted at the Teaching and Research Farm of Rivers State University PortHarcourt, Nigeria, to examine the ability of vetiver and guinea grasses amended with organic manures in remediation of crude oil polluted soil; soil polluted with Bonny light crude oil at 0 and 2% v/w was subjected to a remediation processes using vetiver (Vetiveria zizanioides) and Guinea grass (Panicum maximum) amended with organic manures for a period of twelve months. Two weeks after pollution, poultry and rabbit manures were applied at 0, 10, 20 and 30 tons per hectare respectively. Vetiver and guinea grasses were planted two weeks later. It was fitted in factorial split plots randomized block design. Results of the study revealed that remediation of the soil with grasses degraded the Total hydrocarbon content (THC) to 23 and 21.2% for vetiver and guinea grass respectively, while the quantity of heavy metals removed from the soil were 28.4% and 25.9% for iron, 37.3 and 32.8% for zinc, 35.8 and 30.8% for lead (Pb) and 23.1 and 38.5% cadmium for vetiver and guinea grass respectively. Amendment of the soil with 30 tons’ /ha organic manures increased the quantity of THC degraded to 70.6% and 67.9% for vetiver and guinea grass respectively while the concentration/quantity of heavy metals removed from the soil increased to 58.4 and 54.7% for Fe, 66.9 and 65.1% for Zn, 69.4 and 66.6% for Pb and 80.8 and 71.2%, in Cd for vetiver and guinea grass respectively. The quantity and concentration of THC and heavy metals degraded in the soil was higher in vetiver than guinea grass plots and in vetiver amended with poultry manure than in guinea grass amended with rabbit manure. There was a significant (P<0.05) difference in uptake of THC and heavy metals in plant tissues between vetiver and guinea grass. Vetiver accumulated more of the contaminants in their tissues than guinea grass. Amendment of the soil with organic manures reduced the uptake of the contaminants (THC and heavy metals) from the plant tissues. Generally, both grasses have the capability to remediate crude oil contaminated soil. Augmentation of the two grasses with organic manures enhanced their capability.

Solar-Assisted, Fast, and In Situ Recovery of Crude Oil Spill by a Superhydrophobic and Photothermal Sponge.

Development of a functional sorbent for effective crude oil absorption is essential to address large-scale spilling incidents. Herein, we demonstrate a facile method for preparing a superhydrophobic and photothermal PDMS/CuS/PDA@MF sponge through sequential depositions of PDA, CuS nanoparticles, and a PDMS layer onto a melamine sponge. The optimized composite sponge exhibits a superhydrophobic surface property, high absorption capacity for oils, robust recycling, and excellent photothermal conversion performance. Under sunlight irradiation, the sponge can be rapidly heat up for effectively reducing the viscosity of the surrounding crude oil in order to enhance its fluidity. As a result, uptake of crude oil can be achieved continuously at approximately 5.3 g/min using a peristaltic pump. Overall, we believe that a simple fabrication method from low-cost reagents and excellent crude oil remediation performance render the PDMS/CuS/PDA@MF sponge as an excellent sorbent candidate for remediating crude oil spill.

Remediation of Crude Oil Contaminated Soil, Using Organic Supplement: Effects on Growth and Heavy Metal Uptake in Cassava (Manihot esculenta Crantz)

Field experiments were conducted in 2016 and repeated in 2017 to evaluate the effectiveness of Oil Palm Bunch Ash (OPBA) and Dried Poultry manure (DPM) as organic supplement, applied singly and in combination on growth properties and heavy metal uptake of cassava cultivars grown in crude-oil contaminated soil of the Niger Delta Region, Nigeria. There were four different organic amendments viz: DPM, OPBA, OPBA +DPM and control using TMS 30572, NR8082 and local variety as test crops. Results were elaborated statistically with the use of three-by-four factor variance analysis with ANOVA. Effect of various application of amendment on morphometric parameters of cultivars revealed in 2017 that at 36 weeks after sprouting (WAS), DPM and OPBA +DPM significantly (P≤ 0.05) enhanced plant heights of TMS 3572 and LV but had no influence on number of nodes, stem girth and leaf area. However, the interactions resulted in significant (P≤ 0.05) uptake and concentration of the heavy metals Fe, Cu, and Pb in leaves and Fe in roots ofTMS30572 and NR8082, indicating efficient metal removal by these varieties. Results of amendment also revealed remarkable increment in bacterial and fungal (from 104 to 106 and 103 to 104 ) populations respectively, correlating with reduction in soil total petroleum hydrocarbon (TPH) from 156.45 mg/kg to 146.73 mg/Kg. This is observed to diminish oil toxicity and improve soil status. The response of these cassava varieties to crude oil contamination appears to be optimistic. Consequently crop farmers are adviced against planting cassava and other arable crop at crude oil impacted soil for the risk of uptake of heavy metal in crop tissues. 
 Keywords: Remediation, Heavy metal, Oil-contaminated soil, Organic amendment, Growth properties, Cassava

Treatment of crude oil polluted water using stearic acid grafted mango seed shell (Mangifera indica) composite

This work focuses on the treatment of crude oil polluted water using indigenous adsorbent prepared using mango seed shell. Esterification of mango seed shell (MSS) as a novel composite with high surface area and well-ordered framework of porosity was prepared and kinetic and isotherm modelling of crude oil removal considered. Batch adsorption studies were carried out with the function of oil water ratio, pH and temperature. Material characterization was carried out to ascertain the nature of the composite prepared and its affinity to oil sorption. Surface morphology was investigated with scan electron microscope (SEM). Chemical composition of compounds was investigated using X-ray fluorescent machine while the X-ray diffraction machine (XRD) examined the crystallographic nature of the pretreated mango seed shell (MSS). Salt addition techniques was employed for point zero charge analysis at ionic strengths 0.05 and 0.1 ​mol/dm3. The influence of pH, temperature and oil/water ratio was found to be highly significant and strongly influences oil removal by the composite. SEM analysis showed several changes on the surface of the composite after acid treatment. XRF and XRD revealed that the raw MSS were highly composed of quartz. The point zero charge revealed that the surface of esterified MSS was predominately positive charge at pH ranging between 4.06±0.1 and 4.04±0.1. However, the composite exhibited high adsorption efficiency at a very low pH of 5 with 90.69% of crude oil removal. Isotherm modelling revealed that the composite material was highly matched to Temkin isotherm model with maximum adsorption capacity of 50.80 ​mg/g. The kinetic data fitted well with Bahattacharya-Venkobachor model. The regenerated biomass exhibited high performance and functionality and used successively in different adsorption activities. Therefore, esterified MSS composite is an efficient, economic viable and sustainable adsorbent materials suitable in remediation of crude oil polluted water.