Advanced photocatalysis as a viable and sustainable wastewater treatment process: A comprehensive review.

In our era, water pollution not only poses a serious threat to human, animal, and biotic life but also causes serious damage to infrastructure and the ecosystem. A set of physical, chemical, and biological technologies have been exploited to decontaminate and/or disinfect water pollutants, toxins, microbes, and contaminants, but none of these could be ranked as sustainable and scalable wastewater technology. The photocatalytic process can harmonize the sunlight to degrade certain toxins, chemicals, microbes, and antibiotics, present in water. For example, transition metal oxides (ZnO, SnO2, TiO2, etc.), when integrated into an organic framework of graphene or nitrides, can bring about more than 90% removal of dyes, microbial load, pesticides, and antibiotics. Similarly, a modified network of graphitic carbon nitride can completely decontaminate petrochemicals. The present review will primarily highlight the mechanistic aspects for the removal and/or degradation of highly concerned contaminants, factors affecting photocatalysis, engineering designs of photoreactors, and pros and cons of various wastewater treatment technologies already in practice. The photocatalytic reactor can be a more viable and sustainable wastewater treatment opportunity. We hope the researcher will find a handful of information regarding the advanced oxidation process accomplished via photocatalysis and the benefits associated with the photocatalytic-type degradation of water pollutants and contaminants.

Phosphate adsorption on dried alum sludge: Modeling and application to treatment of dairy effluents.

This study evaluates Alum sludge from drinking water treatment plants for the efficient and cost-effective removal of phosphates from aqueous solutions. Extensive characterization and batch experiments have established that optimal phosphate removal was achieved with a sludge dosage of 20 g L-1 (at an initial phosphate concentration of 100 mg L-1), a pH of 5, a temperature of 23 °C, and a stirring speed of 200 rpm. These conditions significantly reduced phosphate levels, ensuring compliance with legal discharge limits. The Langmuir isotherm, pseudo-second-order kinetic and intraparticle diffusion models best described the adsorption process, highlighting the spontaneous and endothermic nature of the phenomenon. The sludge effectively reduced phosphate concentrations to acceptable levels when applied to dairy effluents. This study underscores the potential of Alum sludge as a viable solution for phosphate management in environmental cleanup efforts.

Adsorptive removal of acid blue dye 113 using three agricultural waste biomasses: The possibility of valorization by activation and carbonization - A comparative analysis.

The presence of various organic and inorganic contaminants in wastewater leads to serious health effects on humans and ecosystems. Industrial effluents have been considered as noticeable sources of contaminating water streams. These effluents directly liberate the pollutants such as dye molecules and heavy metal ions into the environment. In the present study, three biowaste materials (groundnut shell powder, coconut coir powder and activated corn leaf carbon) were utilized and compared for the removal of acid blue dye 113 from aqueous solutions. The characterization study of newly prepared sorbent material (H3PO4-activated corn leaf carbon) and the other utilized sorbents was carried out by Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectrophotometer (FTIR), along with Energy Dispersive X-Ray (EDX) Analysis. The influence of experimental conditions such as pH, initial dye concentration, temperature, contact time, and sorbent dosage on the removal efficiency of the dye were appraised. The adsorption isotherm and kinetic result of acid blue dye 113 adsorption onto the sorbents best obeyed from Sips and pseudo-second-order kinetic model. Overall, the outcomes confirmed that the newly synthesized sorbent material (carbonized H3PO4-activated corn leaf) has superior adsorption capacity, rapid adsorption, and higher suitability for the removal of toxic dyes from the contaminated waters.

Sorption and mechanism studies of Cu2+, Sr2+ and Pb2+ ions on mesoporous aluminosilicates/zeolite composite sorbents.

The research aimed to develop a novel mesoporous aluminosilicate/zeolite composite by the template co-precipitation method. The effect of aluminosilicate (AlSi) and zeolite (NaY) on the basic properties and adsorption capacity of the resultant composite was conducted at different mass ratios of AlSi/NaY (i.e., 5/90, 10/80, 15/85, 20/80, and 50/50). The adsorption characteristics of such composite and its feedstock materials (i.e., aluminosilicates and zeolite) towards radioactive Sr2+ ions and toxic metals (Cu2+ and Pb2+ ions) in aqueous solutions were investigated. Results indicated that BET surface area (SBET), total pore volume (VTotal), and mesopore volume (VMeso) of prepared materials followed the decreasing order: aluminosilicate (890 m2/g, 0.680 cm3/g, and 0.644 cm3/g) > zeolite (623 m2/g, 0.352 cm3/g, and 0.111 cm3/g) > AlSi/NaY (20/80) composite (370 m2/g, 0.254 cm3/g, and 0.154 cm3/g, respectively). The Langmuir maximum adsorption capacity (Qm) of metal ions (Sr2+, Cu2+, and Pb2+) in single-component solution was 260 mg/g, 220 mg/g, and 161 mg/g (for zeolite), 153 mg/g, 37.9 mg/g, and 66.5 mg/g (for aluminosilicate), and 186 mg/g, 140 mg/g, and 77.8 mg/g for (AlSi/NaY (20/80) composite), respectively. Ion exchange was regarded as a domain adsorption mechanism of metal ions in solution by zeolite; meanwhile, inner-surface complexation was domain one for aluminosilicate. Ion exchange and inner-surface complexation might be mainly responsible for adsorbing metal ions onto the AlSi/NaY composite. Pore-filling mechanism was a less important contributor during the adsorption process. The results of competitive adsorption under binary-components (Cu2+ and Sr2+) and ternary-components (Cu2+, Pb2+, and Sr2) demonstrated that the removal efficacy of target metals by the aluminosilicate, zeolite, and their composite remarkably decreased. The synthesized AlSi/NaY composite might serve as a promising adsorbent for real water treatment.

A novel route for preparation of chemically activated carbon from pistachio wood for highly efficient Pb(II) sorption.

Pistachio wood-derived activated carbon prepared by a two-stage process (PWAC-2), conducting two consecutive chemical activation processes with NH4NO3 and NaOH, respectively. The results showed that explosive characteristic of NH4NO3 can primarily be employed to produce a char, with a large surface area and a highly-ordered pore structure, which can be subjected to a second activation process with NaOH to prepare a more suitable activated carbon, with a highly porous structure and useful functional groups, for removal of lead ions from aqueous media. An L25 Taguchi experimental design was used by varying impregnation ratio, activation time and temperature in both pre- and post-activation stages, and the results showed that, in both stages, a small activating agent/precursor and a proportional low activation time suffice for preparation of an advantageous activated carbon for Pb(II) adsorption. A comprehensive study was performed on the equilibrium, kinetic and thermodynamic aspects of Pb(II) adsorption by the new activated carbon. The results exhibited that, having had a high lead adsorption capacity (190.2 mg g-1), a high adsorption rapidness, and thermodynamic favorability, PWAC-2 is a beneficial alternative for utilization in full-scale plants of lead removal from waters and wastewaters.

Metal Organic Frameworks as Desulfurization Adsorbents of DBT and 4,6-DMDBT from Fuels.

Ultradeep desulfurization of fuels is a method of enormous demand due to the generation of harmful compounds during the burning of sulfur-containing fuels, which are a major source of environmental pollution. Among the various desulfurization methods in application, adsorptive desulfurization (ADS) has low energy demand and is feasible to be employed at ambient conditions without the addition of chemicals. The most crucial factor for ADS application is the selection of the adsorbent, and, currently, a new family of porous materials, metal organic frameworks (MOFs), has proved to be very effective towards this direction. In the current review, applications of MOFs and their functionalized composites for ADS are presented and discussed, as well as the main desulfurization mechanisms reported for the removal of thiophenic compounds by various frameworks. Prospective methods regarding the further improvement of MOF's desulfurization capability are also suggested.

Adsorption property of Br-PADAP-impregnated multiwall carbon nanotubes towards uranium and its performance in the selective separation and determination of uranium in different environmental samples.

A newer efficient U(VI) ion adsorbent was synthesized by impregnating Br-PADAP [2-(5-Bromo-2-pyridylazo)-5-(diethylamino)phenol] onto multiwall carbon nanotubes (MWCNTs). The effects of various operation conditions on uranium adsorption (i.e., pH contact time, temperature, and initial uranium concentration) were systematically evaluated using batch experiments. The results indicated that the uranium adsorption on modified MWNCTs (5.571 × 10-3g/mg × min) reached faster equilibrium than that on pristine MWNCTs (4.832 × 10-3g/mg × min), reflecting the involvement of appropriate functional groups of Br-PADAP on the chelating ion-exchange mechanism of U(VI) adsorption. Modified MWNCTs (83.4mg/g) exhibited significantly higher maximum Langmuir adsorption capacity than pristine MWNCTs (15.1mg/g). Approximately 99% of uranium adsorbed onto modified MWNCTs can be desorbed by 2.5mL of 1M HNO3 solution. Therefore, Br-PADAP-modified MWNCTs can server as a promising adsorbent for efficient uranium adsorption applications in water treatment. Subsequently, the proposed solid-phase extraction (using a mini-column packed with Br-PADAP/MWCNT) was successfully utilized for analysing trace uranium levels by the ICP-AES method in different environmental samples with a pre-concentration factor of 300-fold. The coexistence of other ions demonstrated an insignificant interference on the separative pre-concentration of uranium. the detection limit was recognized as 0.14µg/L, and the relative standard deviation was approximately 3.3% (n = 7).

Aloe vera waste biomass-based adsorbents for the removal of aquatic pollutants: A review.

Aloe vera has been cultivated for many centuries for its beneficial properties, finding application in a wide range of medical and health products. Nowadays, the research has also focused on an alternative use of Aloe vera which is related to environmental applications such as clean water technology/wastewater treatment process. In recent years, biosorption has been shown to be a cost-effective and efficient alternative method for removing various pollutants from wastewater and water. This work provides a comprehensive review on using Aloe vera waste biomass-based sorbents, as well as modified counterparts, for the removal of heavy metals, dyes and other pollutants from aqueous media. The discussed biosorbents have been grouped in five categories based on the treatment of the Aloe vera leaves. Adsorption mechanisms, in addition to the significant factors influencing sorption capability like physical and chemical properties of the adsorbent, initial concentration, initial pH and temperature of the solution, dosage and contact time, have been discussed in detail. Furthermore, the applied equilibrium and kinetic models have been also summarized. The history, taxonomy, botany, and applications of Aloe vera are also presented in brief.

Efficient mercury removal from wastewater by pistachio wood wastes-derived activated carbon prepared by chemical activation using a novel activating agent.

Ammonium nitrate (NH4NO3) with explosive characteristics at high temperatures was used as a novel activating reagent to prepare a surface-engineered activated carbon derived from pistachio wood wastes (PWAC). PWAC was characterized and compared with commercial activated carbon (CAC) by textural and morphological properties, surface chemistry, crystal structure, and surface elemental composition. The results indicated that the optimal conditions of PWAC preparation to obtain the highest mercury adsorption capacity were pyrolysis temperature (800 °C), pyrolysis time (2 h), and impregnation ratio (5%). PWAC was of highly regular-shaped and well-developed pores and possessed a large surface area (1448 m2/g) and high total pore volume (0.901 cm3/g). The batch experiments indicated that the adsorption process of Hg(II) was strongly dependent on the solution pH and reached fast equilibrium at approximately 30 min. PWAC (202 mg/g) exhibited a significantly higher maximum adsorption capacity than commercial activated carbon (66.5 mg/g). Adsorbent-adsorbate dispersion interaction plays a major role in the adsorption mechanism, compared to the minor role played by pore filling and reduction mechanism. Overall, ammonium nitrate can be considered a newer activating reagent to prepare promising and low-cost PWAC for effectively Hg(II) removal from water media.

Adsorption and desorption processes of toxic heavy metals, regeneration and reusability of spent adsorbents: Economic and environmental sustainability approach.

A growing number of variables, including rising population, water scarcity, growth in the economy, and the existence of harmful heavy metals in the water supply, are contributing to the increased demand for wastewater treatment on a global scale. One of the innovative water treatment technologies is the adsorptive removal of heavy metals through the application of natural and engineered adsorbents. However, adsorption currently has setbacks that prevent its wider application for heavy metals sequestration from aquatic environments using various adsorbents, including difficulty in selecting suitable desorption eluent to recover adsorbed heavy metals and regeneration techniques to recycle the spent adsorbents for further use and safe disposal. Therefore, the recovery of adsorbed heavy metal ions and the ability to reuse the spent adsorbents is one of the economic and environmental sustainability approaches. This study presents a state-of-the-art critical review of different desorption agents that could be used to retrieve heavy metals and regenerate the spent adsorbents for further adsorption-desorption processes. Additionally, an attempt was made to discuss and summarize some of the independent factors influencing heavy metals desorption, recovery, and adsorbent regeneration. Furthermore, isotherm and kinetic modeling have been summarized to provide insights into the adsorption-desorption mechanisms of heavy metals. Finally, the review provided future perspectives to provide room for researchers and industry players who are interested in heavy metals desorption, recovery, and spent adsorbents recycling to reduce the high cost of adsorbents reproduction, minimize secondary waste generation, and thereby provide substantial economic and environmental benefits.

Valorization of castor seed shell waste as lead adsorbent by treatment with hot phosphoric acid: Optimization and evaluation of adsorption properties.

Lead is used in many industries such as refining, mining, battery manufacturing, smelting. Releases of lead from these industries is one of the major public health concerns due to widespread persistence in the environment and its resulting poisoning character. In this work, the castor seed shell (CSS) waste was exploited for preparing a beneficial bio-adsorbent for removal of Pb(II) ions from water. The raw CSS was modified with H3PO4 at different acid concentrations, impregnation ratios, activation times, and temperatures. An optimum adsorption capacity was observed for CSS modified with 2 M acid, 5 mL g-1 solid to liquid ratio, treated at 95 °C for 160 min. Exploiting acid modification, the SEM, XRD, and FTIR analyses show some alterations in functional groups and the surface morphology of the biomass. The impacts of physiochemical variables (initial lead ions concentration, pH, adsorbent dose and adsorption time) on the lead removal percentage were investigated, using response surface methodology (RSM). Maximum removal of 72.26% for raw CSS and 97.62% for modified CSS were obtained at an initial lead concentration (50 mg L-1), pH (5.7), adsorption time (123 min) and adsorbent dosage (1.1 g/100 mL). Isothermal and kinetics models were fitted to adsorption equilibrium data and kinetics data for the modified CSS and the adsorption system was evaluated thermodynamically and from the energy point of view. Isothermal scrutinization indicated the mono-layer nature of adsorption, and the kinetics experimental outcomes best fitted with the pseudo-second-order, implying that the interaction of lead ions and hot acid-treated CSS was the rate-controlling phenomenon of process. Overall, results illustrated that the hot acid-treated biomass-based adsorbent can be considered as an alternative bio-adsorbent for removing lead from water media.

An overview on the key advantages and limitations of batch and dynamic modes of biosorption of metal ions.

Water purification using adsorption is a crucial process for maintaining human life and preserving the environment. Batch and dynamic adsorption modes are two types of water purification processes that are commonly used in various countries due to their simplicity and feasibility on an industrial scale. However, it is important to understand the advantages and limitations of these two adsorption modes in industrial applications. Also, the possibility of using batch mode in industrial scale was scrutinized, along with the necessity of using dynamic mode in such applications. In addition, the reasons for the necessity of performing batch adsorption studies before starting the treatment on an industrial scale were mentioned and discussed. In fact, this review article attempts to throw light on these subjects by comparing the biosorption efficiency of some metals on utilized biosorbents, using both batch and fixed-bed (column) adsorption modes. The comparison is based on the effectiveness of the two processes and the mechanisms involved in the treatment. Parameters such as biosorption capacity, percentage removal, and isotherm models for both batch and column (fixed bed) studies are compared. The article also explains thermodynamic and kinetic models for batch adsorption and discusses breakthrough evaluations in adsorptive column systems. The review highlights the benefits of using convenient batch-wise biosorption in lab-scale studies and the key advantages of column biosorption in industrial applications.

Recruiting chemical grafting method for surface modification of stainless steel to fabricate a selective sorbent for solid phase microextraction of mercury metal ion.

Keeping selectiveness and efficiency in view with solid-phase microextraction (SPME) of metal ions, this work was aimed at synthesis of a novel modified sorbent on a stainless-steel surface to fabricate a selective and efficient fiber for SPME of mercury ions from real food and biological samples. After the confirmation of sorbent structure grafted on the stainless-steel surface, by different techniques, the synthesized fiber was utilized for extraction and preconcentration of mercury before its measurement by an inductively coupled plasma-optical emission spectroscopy (ICP-OES). For optimizing the efficiency, the influences of various factors on the extraction of Hg (II) ion were scrutinized. The optimized values used for extraction were pH 7.0, adsorption time 8 min, desorption time 5 min, 5 mL of eluent solvent containing nitric acid with concentration of 0.5 mol L-1, and stirring rate of 300 rpm. Underneath optimum condition, the relative standard deviation for 30 extractions, done by one synthesized fiber, was calculated to be 2.89% and for five extractions, done by 5 synthesized fibers, was calculated to be 1.78%. The high performance of the synthesized fiber was checked with high recoveries obtained from 30 successive sorption-desorption cycles, using a unique synthesized fiber. Finally, the suggested procedure was triumphally exploited for extraction and pre-concentration of Hg (II) ion in real food and biological samples.

Graphene-based materials for effective adsorption of organic and inorganic pollutants: A critical and comprehensive review.

Water scarcity has been felt in many countries and will become a critical issue in the coming years. The release of toxic organic and inorganic contaminants from different anthropogenic activities, like mining, agriculture, industries, and domestic households, enters the natural waterbody and pollutes them. Keeping this in view in combating the environmental crises, removing pollutants from wastewater is one of the ongoing environmental challenges. Adsorption technology is an economical, fast, and efficient physicochemical method for removing both organic and inorganic pollutants, even at low concentrations. In the last decade, graphene and its composite materials have become the center of attraction for numerous applications, including wastewater treatment, due to the large surface area, highly active surface, and exclusive physicochemical properties, which make them potential adsorbents with unique physicochemical properties, like low density, chemical strength, structural variability, and the possibility of large-scale fabrications. This review article provides a thorough summary/critical appraisal of the published literature on graphene-, GO-, and rGO-based adsorbents for the removal of organic and inorganic pollutants from wastewater. The synthesis methods, experimental parameters, adsorption behaviors, isotherms, kinetics, thermodynamics, mechanisms, and the performance of the regeneration-desorption processes of these substances are scrutinized. Finally, the research challenges, limitations, and future research studies are also discussed. Certainly, this review article will benefit the research community by getting substantial information on suitable techniques for synthesizing such adsorbents and utilizing them in water treatment and designing water treatment systems.

Production of biochar from Melia azedarach seeds for the crystal violet dye removal from water: combining of hydrothermal carbonization and pyrolysis.

Biochar has shown large potential in water treatment because of its low cost, good textural properties, and high reusability. In this study, two porous biochars were developed from the Melia azedarach seeds via direct pyrolysis process (B-700) and through hydrothermal carbonization followed with pyrolysis (HB-700). They were characterized by morphology, structural characteristics, and surface features and used to adsorb the crystal violet (CV) dye in water environment. Results of the isotherm approaches demonstrated that the removal capacity of these biochars reached 119.4 mg/g for B-700, and 209 mg/g for HB-700 (at 45°C). Also, the Avrami model best fitted the kinetic data. The electrostatic attraction was regarded as one of the adsorptions mechanisms of CV dye. The regeneration tests reveal that both B-700 and HB-700 are good reusable adsorbents. Finally, findings of the study showed that the hydrothermal carbonization method that precede the pyrolysis process can improve significantly the adsorption capacity of the produced biochar.

Adsorption performance of Enterobacter cloacae towards U(VI) ion and application of Enterobacter cloacae/carbon nanotubes to preconcentration and determination of low-levels of U(VI) in water samples.

Keeping the high potential of some microorganisms in adsorption of radionuclides in view, the adsorption properties of Enterobacter cloacae towards uranium were attentively scrutinized, and then it was used for preconcentration of uranium in different samples, using Enterobacter cloacae/carbon nanotube composite. First, using ultrasonic agitation, the effects of operational factors on biosorption of uranium on the inactive Enterobacter cloacae were appraised and modeled by central composite design, and a comprehensive study was performed on the equilibrium, kinetics, thermodynamic, and selectivity aspects of biosorption. The optimization studies along with the evaluations of the adsorption properties revealed that Enterobacter cloacae have a high affinity for fast and selective biosorption of uranium ions, at pH 5.1. Second, the Enterobacter cloacae/carbon nanotube was synthesized, characterized, and utilized for preconcentration of uranium in different samples, using a mini-column packed with the composite. The optimization of operational factors on recovery of uranium, using the central composite design, showed that uranium can be quantitively adsorbed at a sample flow rate lower than 4.5 mL min-1 and the desorption could be accomplished with 3.0 mL HCl 0.6 M solution. Finally, the mini-column was exploited for preconcentration and determination of uranium in different samples. The results revealed the low detection limit (0.015 µg.L-1), high precision (RSDs ≤3.92%), and good accuracy of the proposed procedure.

Use of Chrysosporium/carbon nanotubes for preconcentration of ultra-trace cadmium levels from various samples after extensive studies on its adsorption properties.

Carbon nanotubes were used to immobilize Chrysosporium fungus for building an adequate adsorbent to be used as an desirable sorbent for preconcentration and measurement of cadmium ultra-trace levels in various samples. After characterization, the potential of Chrysosporium/carbon nanotubes for the sorption of Cd(II) ions was scrutinized by the aid of central composite design, and comprehensive studies of sorption equilibrium, kinetics and thermodynamic aspects were accomplished. Then, the composite was utilized for preconcentration of ultra-trace cadmium levels, by a mini-column packed with Chrysosporium/carbon nanotubes, before its determination with ICP-OES. The outcomes vouchsafed that (i) Chrysosporium/carbon nanotube has a high tendency for selective and rapid sorption of cadmium ion, at pH 6.1, and (ii) kinetic, equilibrium, and thermodynamic studies showed a high affinity of the Chrysosporium/carbon nanotubes for cadmium ion. Also, the outcomes displayed that cadmium can quantitatively be sorbed at a flow speed lesser than 7.0 mL/min and a 1.0 M HCl solution (3.0 mL) was sufficient to desorbe the analyte. Eventually, preconcentration and measurement of Cd(II) in different foods and waters were successfully accomplished with good accuracy, high precision (RSDs ≤5.65%), and low limit of detection (0.015 µg/L).

Agricultural waste biomass for sustainable bioenergy production: Feedstock, characterization and pre-treatment methodologies.

The worldwide trend in energy production is moving toward circular economy systems and sustainable availability of sources. Some advanced methods support the economic development of energy production by the utilization of waste biomass, while limiting ecological effects. The use of agro waste biomass is viewed as a major alternative energy source that expressively lowers greenhouse gas emissions. Agricultural residues produced as wastes after each step of agricultural production are used as sustainable biomass assets for bioenergy production. Nevertheless, agro waste biomass needs to go through a few cyclic changes, among which biomass pre-treatment contributes to the removal of lignin and has a significant role in the efficiency and yield of bioenergy production. As a result of rapid innovation in the utilization of agro waste for biomass-derived bioenergy, a comprehensive overview of the thrilling highlights and necessary advancements, in addition to a detailed analysis of feedstock, characterization, bioconversion, and contemporary pre-treatment procedures, appear to be vital. To this end, the current status in the generation of bioenergy from agro biomass through various pre-treatment procedures was examined in this study, along with presenting relevant challenges and a perspective for future investigations.

Polydopamine-modification of a magnetic composite constructed from citric acid-cross-linked cyclodextrin and graphene oxide for dye removal from waters.

The effect of polydopamine (PDA) modification on aminated Fe3O4 nanoparticles (Fe3O4-NH2)/graphite oxide (GO)/ß-cyclodextrin polymer cross-linked by citric acid (CDP-CA) composites were studied for the removal of a cationic dye (methylene blue, MB) and an anionic dye (Congo red, CR) from waters. The micro-structural and magnetic characterizations confirmed the successful preparation of Fe3O4-NH2/GO/CDP-CA and PDA/Fe3O4-NH2/GO/CDP-CA composites. The maximum MB and CR adsorption capacities of Fe3O4-NH2/GO/CDP-CA were 75 mg/g and 104 mg/g, respectively, while the corresponding amounts for PDA/Fe3O4-NH2/GO/CDP-CA composite were 195 mg/g and 64 mg/g, respectively. The dye sorption behaviors of these two composites were explained by their corresponding surface-charged properties according to the measured zeta potential results. Moreover, the high saturation magnetizations and the stable dye removal rate in the adsorption-desorption cycles indicated the good recyclability and reusability of the fabricated composites.

Acenaphthene adsorption onto ultrasonic assisted fatty acid mediated porous activated carbon-characterization, isotherm and kinetic studies.

Adsorbents originated from biological materials play a vital role in the remediation of diverse toxic pollutants due to their high efficacy, low cost and being environmentally friendly. The present study focusses on the palm shell activated carbon obtained from agricultural waste precursor (palm shell) with the aid of oleic acid activation along with ultrasonic assistance and its effective utilization for acenaphthene adsorption from aqueous and real effluent. The synthesized Ultrasonic assisted palm shell activated carbon (UAC) possessed high surface area of 506.84 m2/g and distinct porous structure as depicted by SEM analysis. The outcomes of zero discharge analyses and acenaphthene adsorption results vouchsafed that, using oleic acid as an effective catalyst, is explicitly advantageous to combine with ultrasonic assistance to fabricate a highly efficient adsorbent for acenaphthene removal from aqueous solution. The UAC obtained at the selected parameters levels, such as temperature of 45 °C and ultrasonic time of 40 min, has the adsorption capacity of 52.745 mg/g. Sips isotherm model computed from the experimental data gave the best fit among the examined isotherm models. To complete the study of adsorption properties of UAC towards acenaphthene, kinetic modeling and thermodynamic aspects of the adsorption process were also scrutinized. The kinetic studies proved that pseudo-second order model is compatible with the experimental data and thermodynamic results revealed that the adsorption process is of endothermic nature. Overall, ultrasonic-assisted preparation of activated carbon from palm shell actuated using Oleic acid was found to be a highly efficient adsorbent which was suitable for acenaphthene removal from aqueous solution.