Removal Of Contaminants Research Articles

Application of Micro/Nanomotors in Environmental Remediation: A Review

The advent of self-propelled micro/nanomotors represents a paradigm shift in the field of environmental remediation, offering a significant enhancement in the efficiency of conventional operations through the exploitation of the material phenomenon of active motion. Despite the considerable promise of micro/nanomotors for applications in environmental remediation, there has been a paucity of reviews that have focused on this area. This review identifies the current opportunities and challenges in utilizing micro/nanomotors to enhance contaminant degradation and removal, accelerate bacterial death, or enable dynamic environmental monitoring. It illustrates how mobile reactors or receptors can dramatically increase the speed and efficiency of environmental remediation processes. These studies exemplify the wide range of environmental applications of dynamic micro/nanomotors associated with their continuous motion, force, and function. Finally, the review discusses the challenges of transferring these exciting advances from the experimental scale to larger-scale field applications.

Membrane fouling behaviors in membrane Fenton process without acid-base agents controlled by current density for nanofiltration concentrate treatment

Effective generation of H+ and OH− in the Fenton by electrodes is crucial for addressing the impact of acidity and alkalinity on the environment. In this study, electrolysis was coupled with membrane Fenton for nanofiltration concentrate treatment and membrane fouling behaviors were investigated. The effects of current density and dosage (H2O2 and Fe2+ ) were studied. According to the Box-Behnken design results, both current density and the dosages of H2O2 and Fe2+ positively influenced the removal of organic pollutants, with the former showing the most significant effect. Hydroxyl radical (•OH) oxidized the organic pollutants into intermediates, realizing a removal efficiency of 74.50 %. The anode oxidation and Fenton process effectively degraded fluorescent components, particularly humic acid-like substances. Ammonia nitrogen was degraded by active chlorine produced at the anode, with an average removal rate of 51.36 %. Additionally, an increase in current density enhanced ion exchange membrane fouling. Chemical composition analysis suggested that the membrane was primarily covered with hydroxide crystal substances. The ultrafiltration (UF) membrane analysis indicated that cake layer formation was responsible for the trans-membrane pressure (TMP) increase, and cake-complete was the primary mechanism contributing to UF membrane fouling. The membrane Fenton process without acid-base agents exhibits significant potential for contaminants removal from nanofiltration concentrate and is advantageous for cleaning membrane fouling.

Photothermal-photocatalytic bifunctional highly porous hydrogel for efficient coherent sewage purification-clean water generation

Solar interfacial water evaporation based on photothermal materials presents great potential in tackling global water scarcity and environmental pollution. However, existing photothermal materials still suffer from performance deficiencies like insufficient evaporation rate and unreliable long-term stability, as well as single-function limitations leading to incomplete removal of contaminants from wastewater, severely hindering their practical applications. Herein, we develop a novel, cost-effective, highly porous hydrogel composite integrated with synchronous photothermal and photocatalytic effects by a facile two-step immobilization approach. This method involves an initial sonication-induced pre-polymerization of acrylamide to produce a viscous solution that uniformly disperses TiO2 nanoparticles and single-walled carbon nanotubes (SWCNTs), followed by a secondary in-situ free radical polymerization to achieve stable homogeneous TiO2/SWCNTs/polyacrylamide (PAM) hydrogel composite with an ultrahigh porosity of 88.40 %. Remarkably, the resultant hydrogel composite simultaneously exhibits excellent bifunctional photothermal and photocatalytic performances, including exceptional sunlight absorption of 99.35 %, high evaporation rate of 3.53 kg m−2 h−1, and high photodegradation efficiency of 84.27 % for methylene blue. Furthermore, the water evaporator fabricated with such hydrogel demonstrates consistent desalination performance over 40-day continuous monitoring with salt ion removal rates over 95 %, positioning it as a promising bifunctional material for coherent sewage purification and clean water generation.

Thiol-yne click postsynthesis of imidazole-functionalized cyclodextrin microporous organic network: A remarkable adsorbent for sulfonamide antibiotics

Sulfonamides (SAs) are widely used broad-spectrum antibiotics for treating infections. However, their inevitable residues pose serious threats to human health and agroecosystems. Hence, reasonable design and synthesis efficient adsorbents to remove residual SAs from the environment are crucial and highly desired. In this study, a novel imidazole-functionalized cyclodextrin-based microporous organic network (α-CD-MON-BZ) was designed and synthesized through the specific thiol-yne click post-modification for the efficient removal of SAs. The prepared α-CD-MON-BZ exhibited ultrafast adsorption kinetics (<3 min) and an exceptionally high saturation adsorption capacity (571.4 mg/g) for sulfamethoxypyridazine (SMP). This capacity was much higher than those of other reported adsorbents. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and density functional theory calculations revealed that the adsorption process involves hydrophobic, π–π, hydrogen bonding, host–guest, and electrostatic interactions. Furthermore, α-CD-MON-BZ exhibited favorable reusability and selectivity. This study introduces a new method to construct novel functionalized CD-MONs for highly efficient SAs removal and promotes the design and applications of such materials in contaminant removal.

Graphene oxide and hydroxyapatite-based composite extracted from fish scale: Synthesis, characterization and water treatment application

In this study the removal of hydrocarbon pollutants from refinery waste water has been described through a convenient adsorption technique using a novel composite of graphene oxide (GO) and n-hydroxyapatite (n-HAp). The main aim was to synthesized composite which are not only sustainable and biodegradable but also exhibit high adsorption capacity and selectivity for hydrocarbon pollutants. Both the HAp and GO were synthesized from fish scales in the laboratory. The synthesized material was then characterized by XRD, FTIR, SEM, and EDX. At 40 °C and 80 min of reaction time, the adsorbent utilized in a batch mode study attained a maximum 97 % organic pollutant adsorption rate. The adsorption activity was spontaneous, exothermic, useful, and it adhered to the pseudo-2nd order kinetic model. without noticeably losing its activity, the adsorbent retained a high level of efficiency over four consecutive cycles. Adsorption of hydrocarbon wastes using composite adsorbent was carried out under batch mode of adsorption experiments. We also studied the effect of dose, temperature, time and pH of the solution on adsorption. Ethanol was used to regenerate the adsorbent, and it was then dried at 70 °C for re-use. The SEM investigation showed that the morphology of huge caves is rough, layered, and wrinkled. The oxygen and phosphate containing groups were found via FT-IR analysis. Freundlich and Langmuir kinetic models were used to measure the adsorption behavior by applying them to the adsorption data. The results demonstrated a strong correlation between the Freundlich isotherm model and the real data. This study showed a highly effective and cost-efficient methodology for the removal of toxic hydrocarbon contaminants in refinery wastewater.

Potential of different biobed–biopurification systems in the treatment of domestic sewage

ABSTRACT Four biobed–biopurification systems (BBPS1, BBPS2, BBPS3, and BBPS4) were constructed for the treatment of wastewater. These biobeds were filled with different materials such as rice husk, soil, vermicompost, gravel, and sand as substrates. A total of 5 L of primary treated effluent was provided to each setup and the effluents were analysed after different retention intervals, i.e., 0, 24, 48, and 72 h for different physio-chemical properties. The findings of the experiment showed that BBPS1, BBPS2, BBPS3, and BBPS4 were highly efficient in removing organic impurities but much less efficient in eliminating physical impurities. Much faster removal of the pollutants was achieved in BBPS1 and BBPS2 in comparison to BBPS3 and BBPS4. Both the BBPS1 and BBPS2 beds created favourable circumstances for organic contaminants to biodegrade as BOD removal efficiency was 55.35 and 56.44% and COD removal efficiency was 85.15 and 70.9%, respectively. Both the setups, i.e., BBPS1 and BBPS 2 are also much more efficient for the removal of biogenic contaminants, i.e., 85.7 and 73.2% for nitrate and 65.12249 and 76.99743% for phosphate, respectively. Overall, the performance of BBPS2 proved to be excellent in comparison to other setups, by calculation of its removal efficiency percent for different parameters.

Synthesis and photocatalytic activity of Ag/AgCl for removal of BTX vapors under visible light: modeling by ANN

Abstract Among volatile organic compounds, benzene, toluene, and xylene (BTX) are the most harmful organic compounds and the removal of these harmful compounds is mandatory. In the current study, Ag/AgCl composite was successfully synthesized via deposition–precipitation along with the photoreduction method. The scanning electron microscopy, x-ray powder diffraction, photoluminescence spectroscopy, Fourier transform infrared spectra, and ultraviolet-visible diffuse reflectance spectroscopy were employed to characterize the synthesized products. The photocatalytic property of the products was investigated by evaluating on photodegradation of BTX vapors under the radiation of visible light. The results showed that Ag/AgCl exhibits enhanced visible-light photocatalytic activity compared with AgCl. The strong surface plasmon resonance of metal Ag nanoparticles anchored on the AgCl surface can be responsible for the enhanced visible-light photocatalytic activity of the Ag/AgCl. The influence of the basic operational parameters such as type of BTX, the concentration of BTX, photocatalyst shape, relative humidity, and radiation time on the removal efficiency of BTX was studied. The data obtained from removal tests were modeled by a three-layered feed-forward artificial neural network. The optimized ANN architecture was strong at predicting the removal efficiency of the BTX contaminants with R2 &gt; 0.99 and a very low mean square error. The sensitivity analysis using Garson’s method displayed that all explored process parameters influence the photocatalytic removal of the BTX contaminants. The obtained ANN model is used to predict the photodegradation of BTX at different conditions.

Arsenic Toxicosis in Animals: Mechanism Clinical Manifestations and Treatment Approaches for Arsenic Poisoning in Animals

Arsenic is a naturally occurring element present in the earth in various form (arsenate, arsenite) contaminates soil, water and causes toxicity to animal as well as human beings. The main routes of exposure of humans and most animals to arsenic through the ingestion then absorption through the skin. Animals having Arsenic intoxication showing various form peracute, acute and chronic form. First treatment is to removal of contaminants, emesis is first step (in capable species), followed by activated charcoal with a cathartic and then oral administration of demulcents. If diagnosis were confirmed early treatment should be started with Dimercaprol, even is given within two hours after ingestion of the toxic metal. Intramuscular injection or intravenous injection in peanut oil because of water insolubility was the reason. Supportive therapy include fluid therapy produce additive effect and animal will improve the health condition.

Vision-Transformer Model Validation Image Dataset

The removal of plastic contamination from cotton lint is a critical issue for the U.S. cotton industry. One primary source of this contamination is the plastic wrap used on cotton modules by John Deere round module harvesters. Despite rigorous efforts by cotton ginning personnel to eliminate plastic during module unwrapping, fragments still enter the gin’s processing system. To address this, we developed a machine-vision detection and removal system using low-cost color cameras to identify and expel plastic from the gin-stand feeder apron, preventing contamination. However, the system, comprising 30–50 ARM computers running Linux, poses significant challenges in terms of calibration and tuning, requiring extensive technical knowledge. This research aims to transform the system into a plug-and-play appliance by incorporating an auto-calibration algorithm that dynamically tracks cotton colors and excludes plastic images to maintain calibration integrity. We present the image dataset that was used to validate the design, consisting of several key AI Vision-Transformer image classifiers that form the heart of the auto-calibration algorithm, which is expected to reduce setup and operational overhead significantly. The auto-calibration feature will minimize the need for skilled personnel, facilitating the broader adoption of the plastic removal system in the cotton ginning industry.

Development of Variable Charge Cationic Hydrogel Particles with Potential Application in the Removal of Amoxicillin and Sulfamethoxazole from Water

Cationic hydrogel particles (CHPs) crosslinked with glutaraldehyde were synthesized and characterized to evaluate their removal capacity for two globally consumed antibiotics: amoxicillin and sulfamethoxazole. The obtained material was characterized by FTIR, SEM, and TGA, confirming effective crosslinking. The optimal working pH was determined to be 6.0 for amoxicillin and 4.0 for sulfamethoxazole. Under these conditions, the CHPs achieved over 90.0% removal of amoxicillin after 360 min at room temperature, while sulfamethoxazole removal reached approximately 60.0% after 300 min. Thermodynamic analysis indicated that adsorption occurs through a physisorption process and is endothermic. The ΔH° values of 28.38 kJ mol−1, 12.39 kJ mol−1, and ΔS° 97.19 J mol−1 K−1, and 33.94 J mol−1 K−1 for AMX and SMX, respectively. These results highlight the potential of CHPs as promising materials for the removal of such contaminants from aqueous media.

Synthesis, (bio)degradation, and utilization of starch-derived biopolymers in defined hard waters

Climate change is causing a change in local rainfall, which generally brings with it a reduction in rainfall and, consequently, an increase in water hardness. This study explores the suitability and stability of various dextrin-derived polymers for cation removal in simulated hard water conditions. Thermal analysis and Fourier-transform infrared spectroscopy confirm the polymers' thermal stability and proper formation. Biodegradability assessments reveal KLEPTOSE®LINECAPS (LC) and GLUCIDEX2® (Glu2) dextrin with pyromellitic dianhydride (PMDA) derivatives have higher durability as they were able to endure enzymatic activity. Adsorption experiments at 300 and 600 ppm indicate significant variations influenced by monomer and crosslinker types, with linear monomers demonstrating superior performance. Notably, different crosslinkers exhibit varying affinities for calcium and magnesium ions, with PMDA derivatives excelling for magnesium and citric acid (CA) derivatives for calcium. Kinetic and isotherm studies reveal a favorable trend towards quasi-second-order kinetics and Freundlich isotherm models, attributed to cavity heterogeneity and diverse attachment points as evidenced in existing literature. These findings suggest promising applications for these polymers, traditionally employed for organic contaminant removal, as additional filters to mitigate water hardness.

Unraveling the mechanisms of organic contamination on gold pulse compression gratings: From cluster formation to stratified adsorption

Organic contamination on gold pulse compression gratings significantly hampers the performance of high-power laser systems under intense laser irradiation. Investigating the adsorption mechanisms of organic contaminants on microstructured gratings is essential for addressing contamination issues and mitigating damage. In this article, we determine the microstructured surface aggregation characteristics of volatile dibutyl phthalate (DBP), the stratified distribution pattern of amorphous DBP clusters, and the distribution points of molecules within microstructures using experiments and cross-scale simulations (molecular dynamics and quantum chemistry). Our analysis of the Reduced Density Gradient (RDG) and charge transfer reveals that adsorption between organic molecules and the gold substrate primarily stems from non-covalent van der Waals and electrostatic forces induced by ester functional groups. Based on this theoretical study, we propose the "molecule-substrate" and "bimolecular" adsorption modes of DBP to elucidate the adsorption mechanisms. Investigating organic compounds' distribution and adsorption mechanisms on optical component surfaces is fundamental to high-power laser-induced damage studies. These insights facilitate the efficient, non-destructive removal of organic contaminants from gold gratings, enhancing the energy output threshold of inertial confinement fusion devices.

Hybrid Electrocoagulation–Adsorption Process for Montelukast Sodium Antibiotic Removal from Water

This study addresses the significant environmental challenge of pharmaceutical pollutants by demonstrating the effectiveness of a hybrid electrocoagulation–adsorption (EC-A) technique for removing Montelukast Sodium (MS) from contaminated water. The research was conducted in three stages—adsorption, electrocoagulation, and adsorption using the residual water from the electrocoagulation process. The adsorbent materials were characterised using various analytical techniques: X-ray Diffraction (XRD) for determining the crystalline structure, Energy-Dispersive X-ray Spectroscopy (EDX) for elemental composition, Scanning Electron Microscopy (SEM) for surface morphology, and Fourier Transform Infrared Spectroscopy (FTIR) for identifying functional groups before and after interaction with the pollutants. The adsorption phase achieved optimal results at a pH of 3 and a contact time of 120 min, with a maximum removal efficiency of 99.5% for a starting MS concentration of 50 mg/L using Calcium Ferric Oxide–Silica Sand (CFO-SS) adsorbent. The electrocoagulation phase showed a 97% removal efficiency with a pH of 11, a current density of 20 mA, and a 5 mm electrode distance, achieved in just 20 min. Finally, the combined EC-A process, with the pH of residual water adjusted to 3, further enhanced the removal efficiency to 74%, highlighting the method’s potential for pharmaceutical contaminant removal. These findings underscore the potential of the EC-A technique as a highly effective and adaptable solution for mitigating pharmaceutical contaminants in water.

Effect of light intensity on removal of contaminants in tilapia residual effluents with mocroalgae

Residual aquaculture effluents are discarded into the environment, causing adverse effects on water bodies through eutrophication. Therefore, looking for a treatment that extracts the contaminants and adds benefits by cultivating microalgae in the effluents is necessary. In this research, Chlorella vulgaris and Nannochloropsis oculata were cultivated in aquaculture waste effluent using two lighting conditions (40.5 and 72.9 μmol m–2 s–1). The results show that the time the exponential and stationary phases are reached was not influenced by light, but cell growth, production, and biomass productivity were. The best results were for the condition of 72.9 μmol m–2 s–1 in stationary phase (4.62×107 ± 2.12×105 and 4.45×107 ± 2.33×106 cell mL–1; 0.684±0.124 and 0.718±0.122 g L–1; 0.043 ± 0.008 and 0.048 ±0.008 g L–1 d–1) with C. vulgaris and N. oculata, respectively. Cultures at 72.9 μmol m–2 s–1 and the stationary phase were better for removing nitrates, phosphates, and COD (80-97%, 25-50%, and 43-89%) in microalgae and growth phases. While for ammonium and nitrites, the highest removal efficiency was obtained with 40.5 μmol m–2 s–1 in the stationary phase. Therefore, light intensity is an essential factor to consider when there are high concentrations of contaminants On the other hand, the light intensity of 72.9 μmol m–2 s–1 was also the most suitable for the highest biomass production and productivity in the stationary phase.

Production, Characterization and Application of Biosurfactant for Cleaning Cotton Fabric and Removing Oil from Contaminated Sand

Biosurfactants are a group of environmentally friendly amphiphilic molecules that are applicable in numerous industries as essential biotechnology products, such as food production, cleaning products, pharmacology, cosmetics, pesticides, textiles and oil and gas fields. In this sense, and knowing the potential of these biomolecules, the aim of this work was to produce a biosurfactant, characterize it regarding its chemical and surfactant properties and investigate its potential in the removal of contaminants and in the cleaning of cotton fabrics. The biosurfactant was initially obtained from the cultivation of the microorganism Candida glabrata UCP 1002 in medium containing distilled water with 2.5% residual frying oil, 2.5% molasses and 2.5% corn steep liquor agitated at 200 rpm for 144 h. The biosurfactant reduced the surface tension of water from 72 to 29 mN/m. The toxicity potential of the biosurfactant was evaluated using Tenebrio molitor larvae and demonstrated non-toxicity. The biosurfactant was applied as a degreaser of engine oil on cotton fabric, and showed 83% (2× CMC), 74% (1× CMC) and 78% (1/2× CMC) oil removal. Therefore, the biosurfactant produced in this work has promising surfactant and emulsifying properties with potential for application in various industrial segments.

Enhanced organic pollutant degradation in a two-dimensional Fe-doped crystalline carbon nitride membrane with near 100 % singlet oxygen generation through the Fe–O–N configuration

The singlet oxygen (1O2)-based nonradical AOP process, realized in carbon materials after nitrogen and metal doping, has drawn much attention in recent years. However, the exclusive generation of 1O2 in the specialized two-dimensional (2D) catalytic membranes and the associated contaminant degradation mechanisms remain unclear. Herein, a Fe-doped crystalline carbon nitride (Fe-CCN) material without additional nitrogen doping was developed to preferentially initiate 1O2-based nanoconfined oxidation of organic pollutants in the 2D Fe-CCN membrane/PMS system. Density functional theory calculation revealed that the Fe-O-N configuration formed after Fe doping altered the electronic structure of Fe centers, enhancing PMS adsorption and promoting the thermodynamically favorable generation of the –O* intermediate, leading to fast and highly selective 1O2 generation. EPR characterization and ROS quenching experiment also confirmed that the Fe-CCN activated PMS, generating nearly 100 % 1O2. The Fe-CCN membrane/PMS system exhibited excellent resistance to natural organic matter (NOM) interference and dramatically increased Bisphenol A (BPA) degradation kinetics, approximately 590 times faster than in conventional batch systems. Enhanced 1O2 exposure concentration within the Fe-CCN membrane nanochannels was supported by EPR data and 1O2 exposure simulations. Furthermore, The Fe-CCN membrane/PMS system showed wide pH tolerance, excellent pollutant degradation performance, and high stability. This work underscores the practical significance of 1O2-based oxidation reactions in membrane-confined AOPs for the rapid and efficient removal of organic contaminants from water.

Airborne Microplastics: Challenges, Prospects, and Experimental Approaches

Airborne microplastics are emerging pollutants originating from disposable tableware, packaging materials, textiles, and other consumer goods. Microplastics vary in shape and size and exposed to external factors break down into even smaller fractions. Airborne microplastics are abundant in both urban and natural environments, including water bodies and glaciers, as particles can travel long distances. The potential toxicity of airborne microplastics cannot be underestimated. Microparticles, especially those &lt; 10 µm, entering the human body through inhalation or ingestion have been shown to cause serious adverse health effects, such as chronic inflammation, oxidation stress, physical damage to tissues, etc. Microplastics adsorb toxic chemicals and biopolymers, forming a polymer corona on their surface, affecting their overall toxicity. In addition, microplastics can also affect carbon dynamics in ecosystems and have a serious impact on biochemical cycles. The approaches to improve sampling techniques and develop standardized methods to assess airborne microplastics are still far from being perfect. The mechanisms of microplastic intracellular and tissue transport are still not clear, and the impact of airborne microplastics on human health is not understood well. Reduced consumption followed by collection, reuse, and recycling of microplastics can contribute to solving the microplastic problem. Combinations of different filtration techniques and membrane bioreactors can be used to optimize the removal of microplastic contaminants from wastewater. In this review we critically summarize the existing body of literature on airborne microplastics, including their distribution, identification, and safety assessment.

Surface charge rearrangement modulation of N, P co-doped carbon induced by iron-cobalt phosphide with cationic vacancies for efficient contaminant removal

Cationic vacancies engineering and interfacial engineering are effective strategies for transition metal phosphides (TMPs)-based electrocatalysts to modulate the electronic structure and improve the acidic stability. However, the complexity of the above dual-strategy coupling poses a challenge. Herein, a novel bifunctional electrocatalyst of N, P co-doped carbon-coated iron-cobalt phosphide with cationic vacancies (V-CoFeP@NPC/CC) is synthesized. The physicochemical properties and electrochemical behaviour of V-CoFeP@NPC/CC can be modulated through regulating the cationic vacancies type on CoFeP. Density function theory (DFT) calculation reveals that cationic vacancies, especially bicationic vacancies, endow electrocatalysts stronger charge transfer, strengthened charge rearrangement, optimized intermediate adsorption energy and lower energy barriers. As expected, the resulting V-CoFeP@NPC/CC electrocatalysts displays excellent durability, strong mineralisation capacity and wide adaptability, which can remove nearly 100 % tetracycline within 60 min. Encouragingly, V-CoFeP@NPC/CC also demonstrate satisfactory performance in simultaneous electrooxidative removal of contaminant and hydrogen evolution reaction. This study offers new insight into design and regulate TMPs-based electrocatalysts via introducing cationic vacancies and modulating multi-components.

Zero Valent Iron/Ni (FeNi) bimetallic heterostructure for scalable fabrication of polyvinylidene fluoride/FeNi films and efficient organic contaminant removal under UV/persulfate system

Surface heterogeneity on nano zero-valent iron (nZVI) with an additional metal is expected to enhance the catalytic performance and stability by inhibiting metal corrosion and leaching. The influence of passivation by Ni/NiO on the stability of nZVI is examined through degradation performance of uniformly aged nZVI and nZVI/Ni (FeNi) samples via photo-Fenton like reactions under UV/potassium persulfate (PS) system. FeNi bimetallic nanoparticles (BNPs) exhibits enhanced degradation than bare nZVI as thin layers of Fe3O4 and NiO which contribute towards photocatalytic degradation and anticorrosive effects by nickel inclusion. FeNi BNPs achieve 98 % degradation for pharmaceutical antibiotic levofloxacin (LEVO) within 120 min and 93 % degradation for Methylene Blue dye (MB) within 60 min, outperforming nZVI. To overcome secondary pollution, a stable polyvinylidene fluoride (PVDF)/FeNi film was fabricated to treat the contaminated water. The free-floating PVDF/FeNi film achieved 95 % degradation of MB and 98.3 % degradation of LEVO, maintaining a degradation efficiency of 95.9 % after five successive cycles. FeNi BNPs are also immobilized in the dialysis membrane resulting in 99.9 % and 99 % removal of MB and LEVO respectively. MB degradation using PVDF/FeNi film is validated through the micro reactor model developed in COMSOL Multiphysics. The parameters determined from the Langmuir-Hinshelwood (L-H) kinetic model include an intrinsic rate constant of 2.18 ×10−6 mol m−3 min−1 and an adsorption constant of 1.43 ×1019 m3 mol−1. This work introduces a cost-effective and scalable technique for the efficient remediation of contaminants in wastewater.

Biodegradation of crude oil using bacterial strains isolated from the oil contaminated soil of Shakar Dara oil fields of Pakistan

Oil spillage is an important environmental concern especially in areas near to the oil fields. Microorganisms present one of the most suitable and sustainable way of oil degradation and soil remediation for reuse. The present study was based on the identification of the oil degrading bacteria isolated from the oil contaminated soils located near the Shakar Dara oil fields of Kohat District, Pakistan. The rate of oil degradation by the selected bacterial isolates and the required optimum pH and temperature conditions were also assessed in the present study. Out of the total 15 bacterial isolates, 12 had noticeable oil degrading abilities. In the hydrocarbons sensitivity assays using 5% crude oil, 04 isolates denoted as M1, M2A, M3 and M7 displayed the maximum growth and were chosen for further optimization. The maximum growth was observed at pH 7 and at a mesophilic temperature range (37 °C–40 °C). The selected isolates M1, and M3 were identified as Stenotrophomonas, and Bacillus while, the isolates M2A and M7 were identified as Salmonella spp. respectively. The oil degrading efficiency of Stenotrophomonas sp. M1 was 43% followed by that of Bacillus sp. M3 as 34%. It was concluded that the selected indigenous bacterial strains specifically M1 and M3 aid in the removal of organic contaminants probably owing to some specific enzyme systems synthesized by bacteria. The novel strains being capable of degrading crude oils will help in understanding the activated enzyme machinery and further in the development of an indigenous technology for bioremediation of such contaminated areas.