Economical Sorbent Research Articles

Identification of influential parameters and conditions in heavy metals adsorption onto Cal-LDH-PC using optimization approaches of RSM and Taguchi

Adsorption process plays an important role in the remediation of heavy metals (HMs) from wastewater. A laboratory trial was conducted to investigate effective parameters for improving the bio-adsorption removal of HMs. SEM, EDX, BET, and FTIR techniques were applied to characterize the calcined layer double hydroxide (Cal-LDH), pectin (PC), and Cal-LDH-PC composite prepared from Licorice pomace. The adsorption of zinc (Zn) cadmium, nickel (Ni) and lead (Pb) onto the most efficient sorbent was investigated using RSM methodology with operational factors such as concentration, reaction time, sorbent dose, and pH. The results related to FTIR showed that Cal-LDH-PC had the highest number of functional groups. Based on the SEM results Cal-LDH had a low surface area (9.36 m2 g-1) and a small pore size (9.22 nm). After the modification process (Cal-LDH-PC), the values of surface area and pore size increased by 13-fold (120 m2 g-1) and 1.5-fold (18 nm), respectively. Cal-LDH had high adsorption performance, more cavities, stability, various functional groups, and excessive carbon and oxygen content, which make it efficient and powerful in removing HMs from wastewater. The optimal condition for achieving the removal efficiency (RE%) values of metals was determined to be 80.79 mg L−1, 100 min, 0.167 g L−1, and 9 for concentration, reaction time, sorbent dose, and pH, respectively. Maximum adsorption capacity and RE (%) were 300 mg g−1 and 99% for Zn. According to the results concentration had a major impact on RE% (except for Ni), while for Ni, adsorbent dose had the most significant impact. The present study introduced Cal-LDH-PC prepared from Licorice pomace as a capable, useful and economical sorbent for HMs removal from polluted environments. Taguchi's statistical method is distinguished as an economic method with easier interpretation, while the RSM approach is more accurate, and it can also check the interaction of parameters.

Chromium Disarmament from Veritable Tanneries Sewer Water Utilizing Carbonic Rice Straw as a Sorbent: Optimization and Carbonic Rice Straw Characteristics

This exploration focuses on the removal of chromium from actual tannery wastewater, collected from the HARBY TANNERY factory in Rubiki (Badr City), using an economical sorbent made from activated carbon derived from rice straw (CRS). The CRS sorbent is activated using H3PO4. The experiment aims to assess the impact of various parameters, including chromium initial concentration, sorbent dosage, treatment time, agitation velocity (rpm), sorbent particle size, and solution pH, on chromium removal from tannery wastewater. Structural, morphological, and electronic distinctive of raw and treated CRS, as well as carbonized CRS, were analyzed using FTIR, SEM, and TEM techniques. XRF analysis was conducted to investigate the chemical elemental composition of carbonized CRS before and after sorption. Zeta potential measurement was performed to assess the electrical charges of particles present in a suspension. The adsorption data was tested for both Langmuir and Freundlich adsorption isotherms, and most of the factors suggested that it follows the Langmuir adsorption isotherm with an R2 value of 99.67%. Additionally, adsorption kinetics were performed to identify the reaction order, which exhibited that sorption pursued pseudo-second-order kinetics with a rate constant (k) of 0.0658 g/mg g/min, a high correlation factor (R2) of 99.76%, and an estimated equilibrium chromium ion adsorption capacity (qe) of 1.597 mg/g, which closely matched the experimental data (1.4835 mg/g). The improved surface morphology and increased surface area of CRS resulted in approximately 98.9% chromium removal. Mechanism studies confirmed that intraparticle diffusion is not the sole rate-controlling step, and Boyd’s model demonstrated that film diffusion limited the rate of chromium adsorption. The desorption of chromium from the carbonized rice straw surface could be achieved by up to 96.4% of the sorbed amount by raising the solution pH to 10, indicating the potential reusability of carbonized rice straw for additional adsorption cycles. Finally, a statistical regression analysis and least square multivariate analysis were used to establish a correlation for predicting efficiency, yielding an R2 value of 97.54%.

Deep insights into kinetics, optimization and thermodynamic estimates of methylene blue adsorption from aqueous solution onto coffee husk (Coffee arabica) activated carbon

In the current study, an attempt was made to synthesize coffee husk (CH) activated carbon by chemical modification approach (sulphuric acid-activated CH (SACH) activated carbon) and was used as a valuable and economical sorbent for plausible remediation of Methylene blue (MB) dye. Batch mode trials were carried out by carefully varying the batch experimental variables: SACH activated carbon (SACH AC) dosage, pH, initial dye concentration, temperature, and contact time. The optimum equilibrium time for adsorption by SACH activated carbon was obtained as 60 min, and the maximum adsorption took place at 30 °C. Morphological and elemental composition, crystallinity behaviour, functional groups, and thermal stability were examined using SEM with EDX, XRD, FTIR, BET, TGA, and DTA and these tests showed successful production of activated carbon. The outcomes showed that chemical activation enhanced the number of pores and roughness which possibly maximized the adsorptive potential of coffee husk. The Box-Benken design (BBD) was used to optimize the MB dye adsorption studies and 99.48% MB dye removed at SACH AC dosage of 4.83 g/L at 30 °C for 60 min and pH 8.12, and the maximum adsorption was yielded for sulphuric acid-activated coffee husk carbon carbon with 88.1 mg/g maximum MB adsorption capacity. Langmuir- Freundlich model deliberately provided a better fit to the equilibrium data. The SACH AC-MB dye system kinetics showed a high goodness-of-fit with pseudo second order model, compared to other studied models. Change in Gibbs's free energy (ΔGo) of the system indicated spontaneity whereas low entropy value (ΔSo) suggested that the removal of MB dye on the SACH activated carbon was an enthalpy-driven process. The exothermic nature of the sorption cycle was affirmed by the negative enthalpy value (ΔHo). The adsorptive-desorptive studies reveal that SACH AC could be restored with the maximum adsorption efficiency being conserved after the fifth cycles. Overall, the outcomes revealed that sulphuric acid-activated coffee husk activated carbon (SACH AC) can be used as prompt alternative for low-cost sorbent for treating dye-laden synthetic wastewaters.

Uranium capture from aqueous solution using cement kiln dust; equilibrium and kinetic studies

Contamination of aquatic ecosystems with radioactive nuclides is significantly threaten the human body. So, finding effective and economical sorbents is significant for uranium elimination from an aqueous solution is important. In this study, Cement kiln dust (CKD) is a solid waste produced during the cement production process was utilized as sorbent for the uranium sorption from an aqueous solution. The maximum adsorption of 156.2 mg g−1 at pH 3.0 which reflects good sorption properties for the CKD. All in all, the displayed data declares that the CKD material possess an extraordinary tendency for U(VI) recovery from aquatic environments.

Efficient removal of uranium (VI) from water by a hyper-cross-linked polymer adsorbent modified with polyethylenimine via phosphoramidate linkers

Practical adsorbents with high efficiency are essential to effectively treating wastewater. Herein, a novel porous uranium adsorbent (PA-HCP) having a considerable amount of amine and phosphoryl groups was designed and synthesized by grafting polyethyleneimine (PEI) on a hyper-cross-linked fluorene-9-bisphenol skeleton via phosphoramidate linkers. Furthermore, it was used to treat uranium contamination in the environment. PA-HCP exhibited a large specific surface area (up to 124 m2/g) and a pore diameter of 2.5 nm. Batch uranium adsorptions on PA-HCP were investigated methodically. PA-HCP demonstrated a uranium sorption capacity of >300 mg/g in the pH range of 4–10 (C0 = 60 mg/L, T = 298.15 K), with its maximum capacity reaching 573.51 mg/g at pH = 7. The uranium sorption process obeyed the pseudo-second-order model and fitted well with the Langmuir isothermal. In the thermodynamic experiments, uranium sorption on PA-HCP was revealed to be an endothermic, spontaneous process. Even in the presence of competing metal ions, PA-HCP exhibited excellent sorption selectivity for uranium. Additionally, excellent recyclability can be achieved after six cycles. Based on FT-IR and XPS measurements, both the PO and –NH2 (and/or –NH–) groups on PA-HCP contributed to efficient uranium adsorption as a result of the strong coordination between these groups and uranium. Furthermore, the high hydrophilicity of the grafted PEI improved the dispersion of the adsorbents in water and facilitated uranium sorption. These findings suggest that PA-HCP can be used as an efficient and economical sorbent to remove U(VI) from wastewater.

Adsorption of Methyl Orange and Cr (VI) Onto Poultry Manure-Derived Biochar From Aqueous Solution

In recent years, heavy metals and other organic compound pollution has increased and become a considerable global problem due to its direct impacts on the aquatic ecosystem. This study is aimed to see how efficient the poultry manure-derived biochar is in removing chromium (VI) and methyl orange simultaneously from the aqueous solutions through adsorption. Chromium present in the form of reactive ions such as HCrO4− and Cr2O72− at pH 2–6 values and in stable form, CrO4− at alkaline pH. In this study, biochar was synthesized by the slow pyrolysis of feedstock in a muffle furnace at 550°C temperature with 2 mm particle size. This study provided the biochar with SBET 16.0921 m2/g rough stomata-like pores with a volume of 0.0074 cm³/g, pore diameter 1.84 nm, aromatic groups, and structural diversity. A batch adsorption experiment was conducted to investigate the adsorption efficiency, and mechanism was elucidated by fitting isotherm and kinetic models and result analysis along with the thermodynamics. From the linear Langmuir fit results the maximum adsorption capacity (qmax) of biochar reached up to 20.8 and 19.09 mg g−1 for MO and Cr, respectively. Different operational factors like reaction time, pollutant initial concentration, effect of temperature, and sorbent material dose were studied at pH 4 and initial concentration of 100 mg/L using 2 g of the adsorbent dose. The linear Langmuir well fitted with the experimental data having R2 value of 0.99 and 0.99 for MO and Cr, respectively. From the obtained results, the highest adsorption efficiency reached 88.80% and 90.231% for MO and Cr, respectively.From kinetics study, non-linear pseudo–second-order (PSO) model are highly fitted with the obtained data with R2 of 0.97 and 0.974 for MO and Cr, respectively. The result analysis revealed that HCrO4− and Cr2O72− ions compete with the SO3− to attach on the surface of the sorbent which leads to competitive adsorption of Cr (VI) and MO onto BC. Thermodynamic study presents that the change in Gibbs free energy ΔG° is negative, indicates that the whole process was favorable and completed. The adsorption process was monolayer physisorption, irreversible, and endothermic. Hence, it can be said that this material is environmental friendly and an economical sorbent for high adsorption efficiency.

Adsorption of Bemacid Red by Poly Tetra (Ethylene Glycol) Dimethacrylate Crosslinked with 2-Hydroxypropyl Methacrylate Hydrogels: Equilibrium and Kinetic Studies

Besides others, textile industries are the primary sources of discharging a massive amount of highly colored wastewater. Adsorption can be considered the most economically favorable technology method for removing dyes from wastewater. This paper reports the synthesis of Poly tetra (ethyleneglycol) dimethacrylate crosslinked with 2-hydroxypropyl methacrylate (Poly (TtEGDMA-cross-2-HPMA)) hydrogelsand its application as a novel sorbent to remove bemacid red (ET2) dye from aqueous solution under various operating conditions. The equilibrium adsorption capacity was found 142.82–883.60 mg ET2 g–1 of 1% TtEGDMA. The adsorbent was characterized using Fourier transform infrared radiation (FTIR) and 13carbon solid-state nuclear magnetic resonance spectra (13C-NMR). The effects of the experimental parameters include dye concentration and crosslinked agent concentration. The kinetic sorption uptake for ET2 by Poly (TtEGDMA-cross-2-HPMA) at various initial dye concentrations was analyzed by pseudo-first and pseudo-second models. Two sorption isotherms, namely the Langmuir and Freundlich isotherms, were applied to the sorption equilibrium data. The sorption kinetics of ET2 onto the hydrogels followed the pseudo-second-order kinetics model (R2 = 0.999) and the adsorption equilibrium data obeyed the Langmuir isotherm model (R2 = 0.999). It can be concluded that Poly (TtEGDMA-cross-2-HPMA) is an alternative economic sorbent to more costly adsorbents used for dye removal in wastewater treatment processes.

Comparative Study between Imprinted Polymer Technology and Economic Adsorption Methodologies for the Removal of Arsenic Species from Water

Among the various arsenic sources in the environment, water may pose the greatest threat to human health. Arsenic and its compounds are known to have adverse health effects on humans, including skin cancer, bladder cancer, kidney cancer, and lung cancer, as well as vascular diseases of the legs and feet. There are a few separation methods that have been studied to remove arsenic species from water. Methods to remove arsenic species such as adsorption and ion exchange, coagulation and flocculation and membrane filtration have been developed to remove arsenic species from water. However, certain separation methods require a sophisticated equipment and are too expensive. From the different possible methods, this review is based in adsorption studies using imprinted polymer technology and economic sorbents as a media to remove arsenic from water. The details of adsorption processes for imprinted polymer technology have been discussed briefly and the comparative properties for arsenic species removal using different types of sorbents has been addressed significantly for being a user-friendly, highly extended and inexpensive methodology. However, a few drawbacks for each sorbent have been determined and the details was included in this review.

Walnut bloom powder as a waste-based sorbent for cationic dyes removal: equilibrium, kinetic, and thermodynamic studies

In the present study, for the first time, walnut bloom (WB) powder was used as a natural and economic sorbent for the removal of methylene blue (MB) from an aqueous solution. This new biosorbent was characterized using the following techniques: scanning electron microscopy (SEM), X-ray diffraction (XRD), COHNS, BET (Brunauer–Emmett–Teller) analysis, and Fourier transform infrared (FTIR) spectroscopy. MB removal efficiency and its adsorption onto WB powder were tested in a batch system by varying parameters such as initial dye concentration, contact time, pH, temperature, and dosage of biosorbent in which the removal percentages of ∼92% was achieved under the optimum conditions. Equilibrium data and adsorption isotherms fit well with the Langmuir model (R2 = 0.999, 0 < RL < 1) with a maximum monolayer adsorption capacity of 46 mg g−1. The chemical kinetics of MB adsorption followed the pseudo second-order model. Also, the magnitude of thermodynamic functions identified the removal of MB. ΔH° of –7.32 kJ mol−1and ΔS° of –4.32 kJ mol−1indicated the spontaneity, exothermicity, and favorability of the adsorption process at room temperature.

Biochar of Spent Coffee Grounds as Per Se and Impregnated with TiO2: Promising Waste-Derived Adsorbents for Balofloxacin.

Biochars (BC) of spent coffee grounds, both pristine (SCBC) and impregnated with titanium oxide (TiO2@SCBC) were exploited as environmentally friendly and economical sorbents for the fluroquinolone antibiotic balofloxacin (BALX). Surface morphology, functional moieties, and thermal stabilities of both adsorbents were scrutinized using SEM, EDS, TEM, BET, FTIR, Raman, and TG/dT analyses. BET analysis indicated that the impregnation with TiO2 has increased the surface area (50.54 m2/g) and decreased the pore size and volume. Batch adsorption experiments were completed in lights of the experimental set-up of Plackett-Burman design (PBD). Two responses were maximized; the % removal (%R) and the adsorption capacity (qe, mg/g) as a function of four variables: pH, adsorbent dosage (AD), BALX concentration ([BALX]), and contact time (CT). %R of 68.34% and 91.78% were accomplished using the pristine and TiO2@SCBC, respectively. Equilibrium isotherms indicated that Freundlich model was of a perfect fit for adsorption of BALX onto both adsorbents. Maximum adsorption capacity (qmax) of 142.55 mg/g for SCBC and 196.73 mg/g for the TiO2@SCBC. Kinetics of the adsorption process were best demonstrated using the pseudo-second order (PSO) model. The adsorption-desorption studies showed that both adsorbents could be restored with the adsorption efficiency being conserved up to 66.32% after the fifth cycles.

Eco-Friendly and Economical Oil Adsorbents Based on PUF and Chitin

Industrialization and modernization have led to a rapid increase in the amount of solid waste around the globe. To reduce the amount of solid waste that is discharged into the environment, it is necessary to select materials that have high reusability and recyclability. This study evaluates the reusability of the grafted oil adsorbent PPU10M based on polyurethane foam (PUF) and chitin. The result shows that the sorbent PPU10M can reuse up to 20 cycles after sorbent regeneration by the mechanochemical method. The amount of adsorbed oil is recovered up to 91.5%. The use of waste sorbents as the filler into the process synthesis of the oil sorbent containing waste is studied in this work. The results present that the sorbents containing 5% mass of the waste have the oil capacity equivalent to the sorbent without waste. At the same time, the water adsorption of this material reaches lower than in comparison with the non-waste material. This is indicated that the sorbent PPU10M not only has high oil adsorption capacity but also has good reuse and recycling ability. Thus, it is considered that PPU10M is a potential, eco-friendly, and economical sorbent for oil spill removal.

Efficient separation of strontium radionuclides from high-salinity wastewater by zeolite 4A synthesized from Bayer process liquids

The efficient, selective, and economical sorbents for the removal of Sr radionuclides are largely needed for the decontamination of effluents with high salinity. In this study, the removal of Sr was investigated using the zeolite produced from the Bayer process liquids. Based on the XRD, SEM/EDS analysis, the product was pure and highly crystalline zeolite 4A (Z4A). Removal of Sr was fast (5 min for 100% removal at 8.80 mg/L), with high maximum sorption capacity (252.5 mg/L), and independent on the initial pH in the range 3.5–9.0. Specific sorption of Sr by protonated groups on the Z4A surface was operating in addition to ion-exchange with Na ions. The selectivity of Z4A decreased in the order Sr > Ca > K > Mg > Na. 84% of Sr was separated from seawater within 5 min, at the Z4A dose of 5 g/L, while efficiency increased to 99% using the dose of 20 g/L. Desorption of radioisotope 89Sr from seawater/Z4A solid residue was very low in deionized water (0.1–0.2%) and groundwater (0.7%) during 60 days of leaching. Z4A is a cost-effective, selective, and high-capacity medium for Sr removal, which provides high stability of retained radionuclides.

Enhanced CO2 capture using organic acid structure modified waste eggshell derived CaO sorbent

In this study, the waste eggshell has been utilised to synthesise structure modified CaO using organic acids and employed for CO2 capture in the thermogravimetric analysis (TGA) based systems. Different characterisation techniques were used such as XRD, SEM/EDS, XRF, N2 sorption-desorption (BET) and TGA to investigate the suitability for CO2 adsorption. The modified CaO using organic acids showed high surface area, easy upgradation of pore structure makes the CaO a suitable sorbent for CO2 capturing as an economical sorbent. Three of the organic acid modified sorbent achieved the highest conversion and stability over a period of 20 cycles. Citric acid modified sorbent (CaO CA-10%) obtained a CO2 uptake of 0.38 g CO2/g sorbent (CaO conversion of 55%) that was highest among the acid used whereas in term of stability malic acid modified sorbent (CaO MA-10%) has the lowest average decay rate of 4.43 mg CO2/cycle as compared to various acids used in this work. It is concluded that modified surface structure by employment of organic acids lead to the reduction of sintering and led towards better sorbents performance towards CO2 capturing for multiple cycles.

Synergistic effects of Fe-Mn binary oxide for gaseous arsenic removal in flue gas

High-efficient and economic sorbents are highly desired for arsenic (As) emission control in flue gas from coal-fired power plant. A series of Fe-Mn binary oxides were prepared by a facile method, and their behaviors for gaseous arsenic removal in flue gas were investigated. The binary oxide exhibited a remarkable synergistic effect for arsenic removal compared with Mn or Fe monometallic oxide. The possible effects of CO2, NO, SO2, and O2 on the removal performance were also studied. The adsorption ability was excellent and stable in simulated flue gas conditions. X-ray photoelectron spectroscopy (XPS) and high-performance liquid chromatography atomic fluorescence spectroscopy (HPLC−AFS) coupling system were applied to analyze the species of surface-adsorbed arsenicals and soluble arsenicals. It was confirmed that the good sorption performance resulted from oxidation of As2O3 (As(III)) to As2O5 (As(V)) by Mn oxide and followed by efficient adsorption of As(V) on Fe oxide. Considering the toxicity of pentavalent arsenicals is lower than trivalent arsenicals, the oxidation of arsenic compounds can not only enhance its removal capacity but also decrease the toxicity of arsenicals after capture.

Feasibility of radioactive cesium and europium sorption using valorized punica granatum peel: kinetic and equilibrium aspects

ABSTRACT This study assesses the sorption characteristics of Punica granatum (pomegranate) peel as an economical sorbent, to decontaminate radioisotopes cesium and europium from aqueous solutions. In this respect, Punica granatum peel (virgin and modified by sodium dodecyl sulfate) had been prepared from the byproduct of numerous industries. The physical and chemical characteristics of prepared sorbents were determined using FTIR, TGA, DTA, SEM, XRD, and pHPZC. The effects of process parameters comprising medium pH, initial concentration, contact time and temperature on 137Cs and 152+154Eu sorption efficiency were investigated. Desorption of the investigated radioactive materials increased as the concentration of desorbing agent increased especially NaOH more than HNO3. Kinetic analysis study showed that the chemical reaction is the rate-determining step. Reaction equilibrium isotherm for both studied ions follows the Langmuir and Temkin model and the sorbent has a higher affinity to stabilize Europium more than Cesium ions.

A polyurethane-based thin film for solid phase microextraction of pyrethroid insecticides.

This work introduces polyurethane (PU) as an efficient and economic sorbent for thin film solid phase microextraction of pyrethroid insecticides, specifically of bifenthrin, fenpropathrin, lambda-cyhalothrin, permethrin, cypermethrin, flucythrinate, fenvalerate and deltamethrin. The PU film is immersed into chrysanthemum tea under ultrasonication for the adsorption of the analytes, and the analytes are desorbed by a mixture of hexane and ethyl acetate and then quantifiedby gas chromatography with electron capture detection. The film type, adsorption temperature, extraction time, sample condition, and desorption procedure were optimized. The adsorption capacity and robustness of the PU film is found to be excellent for analysis of pyrethroids in chrysanthemum tea. The limits of detection and method limits of detection range from 0.05-0.5μgL-1 and 0.0003-0.003μgL-1, respectively. The relative recoveries from spiked samples are between 84.5 and 104.1%, and enrichment factors up to 188. The method was validated through blind split analyses of chrysanthemum tea infusion and ready-to-drink samples with liquid-liquid extraction. Good agreement between the two approaches shows the method to have an accuracy that is similar to that of the conventional technique. Compared with other reported approaches, the PU-based method exhibites a higher sensitivity, easier operation, lower costs and less matrix effects. Graphical abstract Schematic representation of the use of a polyurethane film as an efficient and economic sorbent for the microextraction of 8 pyrethroids by gas chromatography. This method exhibites excellent performance of accuracy, sensitivity, and robustness, demonstrating its potential of application in the analysis of complex matrix.

Polymer Supported Carbon for Safe and Effective Remediation of PFOA- and PFOS-Contaminated Water

Powdered activated carbon (PAC) is an economical sorbent for removing micropollutants from water, but it generates hazardous dust that is flammable and a respiration hazard. Additionally, the fine particles of PAC can cake and block filters and membranes, complicating its use in continuous processes. In this study, we present a sulfur polymer support for PAC that overcomes these problems. The blend of the sulfur polymer and PAC generates low dust and it does not block filters. The utility of the sorbent is demonstrated in the remediation of water contaminated with perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), persistent micropollutants that currently threaten water safety worldwide. Fundamental discoveries of PFOA self-assembly are also reported, as well as testing on a field sample of contaminated surface water.

Improved sorption of reactive black 5 by date seed-derived biochar: isotherm, kinetic, and thermodynamic studies

ABSTRACTIn the present investigation, date seed-derived biochar was applied as economic and effective sorbent for remediation of reactive dye from contaminated solutions. Biochar produced at 350°C through pyrolysis process exhibited reactive black 5 (REB5) sorption capacity 2.7 times higher than virgin date seeds. The surface of biochar was analyzed through Fourier transform infrared and scanning electron microscope data. The maximum REB5 uptake determined through the Langmuir model was found to be 113.4 mg/g. The REB5 sorption kinetics were accurately described by the pseudo-first-order model than pseudo-second-order model. Thermodynamic parameters indicated that REB5 sorption was spontaneous, feasible, and endothermic process.

Clay Adsorption Perspective on Petroleum Refining Industry

Clays are the most utilized minerals and considered very efficient and economical sorbents according to their chemical and physical properties. Clays are enjoying rapid popularity in the petroleum refining industry for the various processes such as adsorption and separation. Removal of many components such as sulfur, heavy metals, colors and separation of different hydrocarbon groups of crude oil and petroleum fractions can be carried out by clay adsorption. The present review summarizes the using of clay as adsorbent in several petroleum refining processes such as desulphurization, deasphalting, waste oil recovery, bleaching, corrosion reduction, heavy metals removal and other. One of the simplest, easiest and efficient separation processes used in different industries is adsorption. Review results show that different types of clay are obtainable and used in many applications. Clay adsorption can be enhanced the treatment and finishing of crude oils and petroleum fractions through several modifications such as metals impregnation, acid and thermal activations. Bentonite clays promote the highest adsorption capacity to remove sulfur and a high bleaching potential. Attapulgite clay is effective in decolorization and neutralization any petroleum oil. Impregnation of NiO nanoparticles into kaolin improves the asphaltenes adsorption. Several modified as well as unmodified clays promote the highest removal efficiency of Ni and V from crude oil. Additionally, the adsorption pre-treatment affects the reduction in corrosion yields and the corrosion rate.

Development of magnetic dispersive solid phase extraction using toner powder as an efficient and economic sorbent in combination with dispersive liquid–liquid microextraction for extraction of some widely used pesticides in fruit juices

In this study, for the first time, a magnetic dispersive solid phase extraction method using an easy–accessible, cheap, and efficient magnetic sorbent (toner powder) combined with dispersive liquid–liquid microextraction has been developed for the extraction and preconcentration of some widely used pesticides (diazinon, ametryn, chlorpyrifos, penconazole, oxadiazon, diniconazole, and fenazaquin) from fruit juices prior to their determination by gas chromatography–flame ionization detection. In this method, the magnetic sorbent is mixed with an appropriate dispersive solvent (methanol–water, 80:20, v/v) and then injected into an aqueous sample containing the analytes. By this action the analytes are rapidly adsorbed on the sorbent by binding to its carbon. The sorbent particles are isolated from the aqueous solution in the presence of an external magnetic field. Then an appropriate organic solvent (acetone) is used to desorb the analytes from the sorbent. Finally, the obtained supernatant is mixed with an extraction solvent and injected into deionized water in order to achieve high enrichment factors and sensitivity. Several significant factors affecting the performance of the introduced method were investigated and optimized. Under the optimum experimental conditions, the extraction recoveries of the proposed method for the selected analytes ranged from 49–75%. The relative standard deviations were ≤7% for intra- (n = 6) and inter-day (n = 4) precisions at a concentration of 10 μg L–1 of each analyte. The limits of detection were in the range of 0.15–0.36 μg L–1. Finally, the applicability of the proposed method was evaluated by analysis of the selected analytes in some fruit juices.