Adsorption kinetics, isotherm, and thermodynamics studies of phytochemical-assisted synthesized ZnO nanoparticles for the removal of selected heavy metals from abattoir wastewater

Textile dye removal from aqueous solutions using cheap MgO nanomaterials: Adsorption kinetics, isotherm studies and thermodynamics

Soluble starch-functionalized graphene oxide composite (GO-starch) was prepared by a facile esterification reaction. And the composite was used as a novel adsorbent for the removal of Cd(II) from aqueous solution. The chemical composition and morphology of the GO-starch was investigated by fourier transform infrared spectroscopy, scanning electron microscopy and Raman spectroscopy. To evaluate the effects of the adsorption of Cd(II) by GO-starch, batch adsorption studies were performed to optimize the major parameters such as contact time, pH, initial concentration and temperature. The maximum uptake capacity of Cd(II) was 43.20 mg/g under the optimal conditions. Furthermore, the adsorption kinetics, isotherms and thermodynamics of Cd(II) on GO-starch were also investigated. The experimental data indicated that the adsorption kinetics and adsorption isotherms of Cd(II) on GO-starch were well fitted by pseudo-second-order kinetic model and Langmuir isotherm model, respectively. The adsorption thermodynamic parameters were calculated as ΔG 0 < 0, ΔH 0 > 0 and ΔS 0 > 0, respectively. The thermodynamic parameters indicated that the adsorption process was endothermic, feasible and spontaneous. Due to its high adsorption capacity for Cd(II), the GO-starch might have considerable potential for the aqueous removal of metal ions. Soluble starch-functionalized graphene oxide composite (GO-starch) was prepared and used as a novel adsorbent for the aqueous removal of Cd(II). The chemical composition and morphology of the GO-starch was characterized by fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and Raman spectroscopy. Batch adsorption experiments were performed to optimize the major parameters such as contact time, pH, initial concentration and temperature. The maximum uptake capacity of Cd(II) was 43.20 mg/g under the optimal conditions. The adsorption kinetics and adsorption isotherms were well fitted by pseudo-second-order kinetic model and Langmuir isotherm model, respectively. The adsorption thermodynamic parameters were ΔG 0 < 0, ΔH 0 > 0 and ΔS 0 > 0, indicating that the Cd(II) adsorption process was spontaneous, endothermic and feasible.

The objective of this work was to characterize and study the behavior of the adsorption process of cellulose/biochar cryogels through isotherm models and adsorption kinetics. The cryogels were produced from a cellulose suspension obtained by mechanical fibrillation of 0.75 and 1.5% w/w unbleached long-fiber cellulose of the Pinus elliotti species. Into this suspension, 5, 10, and 20% w/w (relative to cellulose mass) biochar were added; then, the suspension was frozen and freeze-dried. After this, 2 mL of methyltrimethoxysilane (MTMS) was deposited on the cryogels. Characterization analyses were performed on the cryogels, including specific mass and porosity and sorption capacity, in addition to the study of adsorption kinetics and isotherms. The cryogels showed a porosity of above 90% and a specific gravity of less than 0.035 g cm-3. The heterogeneous sorption capacity varied according to the concentration of cellulose used, and with the addition of 5% w/w biochar in the cellulose cryogel, the highest sorption capacity was obtained, 73 g g-1 of petroleum and 54 g g-1 of SAE20W50 oil. In the study of adsorption isotherms, the Freundlich model best fitted the process. Therefore, it was concluded that the process of petroleum adsorption by the cellulose cryogel occurs in multiple layers. In addition, the cellulose/biochar cryogel developed in the present work is suitable for use in the adsorption of organic liquids.

Metal-organic frameworks (MOFs) are a prominent class of materials due to their large surface area and customized structures. This gives them specificity and high adsorption capacity while they lack mechanical strength and reusability. Integrating MOFs with polysaccharide matrix may retain MOF characteristics along with imparting structural integrity. In the present study, zirconium MOF-based fenugreek composite (FG/Zr-AIPA) beads were synthesised by a single droplet method and utilised for removal of Cr(VI), Pb(II) and Fe(III) from aqueous solution. The structure, morphology and composition of beads were evaluated by FTIR, XRD, TGA, BET, FESEM, EDX, XPS and zeta potential analysis. Adsorption isotherm, kinetics and thermodynamics were studied for Cr(VI), Pb(II) and Fe(III) adsorption. Adsorption kinetics and isotherm study revealed that all the metal ions were adsorbed through a monolayer chemisorption process. The maximum adsorption capacity was 344.43, 270.02 and 223.21mgg-1 for Cr(VI), Pb(II) and Fe(III), respectively, based on the Langmuir isotherm study. The thermodynamics study revealed that the interaction between the metal ions and the composite beads was spontaneous and endothermic. The FG/Zr-AIPA composite beads exhibited good reusability for the removal of Cr(VI), Pb(II) and Fe(III). The results open new possibilities for the preparation of polysaccharide MOF-based composite beads which exhibit substantial potential for water treatment applications.

Among the most hazardous environmental issues nowadays is heavy metal pollution. One efficient technique for eliminating wastewater that contains heavy metals is adsorption. In order to assess an adsorbent's effectiveness and construct an adsorption system, the maximal adsorption capacity, the adsorption process and the movement of mass phases can all be determined in kinetics models and adsorption isotherms. This study examined tea waste treated with sulfuric acid as an inexpensive alternative adsorbent for the removal of Cu (II) ions from aqueous solution. 1M H2SO4 was added to the tea waste, and it was heated to 150°C for 24 hours. Tea waste and tea factory wastewater was taken from Nyamache tea Factory. The adsorption kinetics and isotherms of heavy metals by both modified and unmodified biomass tea waste were compiled and thoroughly examined in this paper. biomass quantity (0.1 to 1.0 g), pH levels (2.0 to 10.0), all had an impact on the biosorption procedure. The findings from the study show the optimum pH of the modified tea waste as 6 and for unmodified tea waste as 5.9. The optimum adsorbent dosage for modified tea waste as 0.7 grams and for the unmodified tea waste as 0.8 grams. The adsorption capacities of modified and unmodified tea waste were 14.144 and 12.706 respectively, the adsorption capacity for modified tea waste were comparatively greater than those of unmodified tea waste. For both modified and unmodified tea waste, the adsorption data fit the Langmuir isotherm model better than the Freundrich model, with correlation coefficients of 0.9477 and 0.9402, even though the adsorption kinetics matched pseudo-second-order kinetics (R=0.9999). The findings show that copper (ll) ions can be removed from household wastewater by using modified tea waste and unmodified tea waste.

The development of cellulose aerogels for the adsorption of petroleum becomes interesting due to the cellulose being obtained from biomasses, thus being a natural and biodegradable source. The study of adsorption kinetics and isotherms for this material and application are not reported in the literature. So the objective of this work was to evaluate the behavior of the adsorption process through isothermal and kinetic adsorption models of cellulose cryogels. The cryogel was produced from a cellulose suspension in water obtained by mechanical fibrillation of 1.5% (w/w) unbleached long fiber cellulose of the species Pinus elliotti. The suspension received 4% (w/w) of sodium hydroxide NaOH, and subsequently was frozen and freeze-dried. After freeze-drying, 2 mL of methyltrimethoxysilane (MTMS) was vapor deposited in the cryogel. The study of the kinetics (pseudo-first and second order) and isotherms (Langmuir and Freundlich) of adsorption was performed. Cryogels presented a porosity of 93.51 ± 0.77% and a specific mass of 0.034 ± 0.004 g cm−3, in addition to being hydrophobic (water contact angle of 128.7° ± 3.81). Heterogeneous adsorption capacity was of 23.19 g g−1 with 94% oil retention. In the study of isotherm and kinetics of adsorption, the models that fit the process were pseudo-second order and Langmuir, respectively. Based on the results the adsorption process of oil by the cellulose cryogels samples occurs in monolayer. In addition, the cellulose cryogel developed in the present work is suitable for use in the adsorption of petroleum.

This work has demonstrated the potential utility of raw pumpkin seed shells (PSS) as a low-cost solid adsorbent for methylene blue (MB) adsorption. PSS have investigated surface functional groups with FTIR (after and before adsorption), crystal structure with XRD, and surface morphology with SEM-EDX. Biosorption parameters were examined contact time, pH, solution temperature, and initial concentration. This research was conducted to analyze adsorption processes involved in adsorption of MB onto crude PSS by gaining essential knowledge from the study of equilibrium adsorption kinetics, isotherms, and thermodynamics. It was determined whether four models-Langmuir, Temkin, Freundlich, and D-R models-fit experimental data derived from adsorption isotherms. In addition, the accuracy of fits of three models to experimental data derived from adsorption kinetics were tested, namely, the Elovich, pseudo-first order, and pseudo-second order models. Biosorption of MB on PSS is exothermic and spontaneous according to thermodynamic analysis. FTIR (Fourier transform infrared spectroscopy) studies show significant changes in the absorption values, shapes and positions of bands both before and after solute adsorption. It was found that there are two MB adsorption mechanisms: electrostatic attraction and hydrogen bonding.

In this study, the adsorption of reactive yellow dye which is one of the most commonly used soluble dyes in textile industries was studied using modified wheat straw, the surface of raw wheat straw was modified with a cationic surfactant CTAB. to understand the adsorption behavior of the reactive yellow, dye the adsorption kinetics and the adsorption isotherm studies have been investigated. Batch experiments was carried out with an initial concentration of 10 mg/L with 0.5 gm of adsorbent to study the contact time of equilibrium and then the adsorption mechanism process using three kinetic models; Pseudo-first, second order and intra-particle model. Isotherm studies was carried out at three different adsorbent amounts (0.1, 0.2, 0.4, 0.6, 0.8 and 1.0) gm to predict the type of adsorption process on the surface (chemical or physical) using three isotherm models; Langmuir, Freundlich and BET models. The results showed that the pseudo-second order is best fitted, intra-particle diffusion kinetic model fitted well to experimental data and is not the only controlling step of adsorption rate, and the adsorption isotherm follows both Langmuir and Freundlich models referring to the chemical adsorption.

Highly efficient and rapid removal of a toxic dye: Adsorption kinetics, isotherm, and mechanism studies on functionalized multiwalled carbon nanotubes

Evaluation of a novel activated carbon/graphene oxide as an efficient composite adsorbent for the removal of herbicide 2,4-Dichlorophenoxyacetic acid: Adsorption isotherm and kinetics study

The removal efficiency of As(III) by kaolin clay modified by Fe-Mn bimetal oxides was successfully evaluated. Modification of kaolin clay by Fe-Mn oxides increased the surface area of the kaolin clay from 19.2 to 29.8 m2/g and further decreased the pore diameter from 9.54 to 8.5 nm. As(III) removal efficiency was optimum at pH 8. The adsorption isotherm data fitted well to Langmuir adsorption isotherm model with a maximum adsorption capacity of 2.93 mg/g at initial As(III) concentration range of 1 to 30 mg/L. The adsorption kinetics data was described better by pseudo-second order of reaction kinetics indicating that As(III) sorption occurred via chemisorption. Thermodynamics studies revealed that As(III) adsorption occurs spontaneously and the reaction is exothermic in nature. Compared to other reported adsorbents, Fe-Mn bimetal kaolin showed higher adsorption capacity making it a suitable candidate for As(III) removal from groundwater.

This study focuses on the synthesis and characterization of the molecularly imprinted polymer (PPy-MIP) to remove 17β-Estradiol (E2) from aqueous solutions. The MIP was synthesized using a non-covalent procedure, incorporating the target compound, E2. To synthesis PPy-MIP, a mixture of 300 μl pyrrole and 50 ml distilled water was stirred for 30 min. After adding 3 g ferric chloride as an oxidant, the solution was mixed for 2 h and stored for 48–72 h. MIP capability is compared with a non-molecularly imprinted polymer (NIP) as a control. Various factors such as pH, contact time, dosage, temperature, and concentration were investigated to optimize the performance of the PPy-MIP. The structure of the MIP was confirmed using field emission scanning electron microscopy (FESEM), infrared spectrophotometric spectrum (FTIR), and X-ray diffraction (XRD). The efficiency of the PPy-MIP in removing E2 was obtained 99.97% at optimum condition; while, the NIP achieved a removal efficiency of 69.9%. Adsorption data were fitted with Langmuir isotherms (R2 0.98) and pseudo-second-order kinetics (R2 0.99). The selectivity of the PPy-MIP toward similar compounds such as progesterone and cholesterol was also examined. To understand the adsorption process, thermodynamics, kinetics, and isotherm studies were performed. The MIP showed good reproducibility with only a slight decrease in removal efficiency after multiple absorption and reabsorption cycles. The adsorption of E2 by the MIP followed Langmuir adsorption isotherm and second-order adsorption kinetics. MIP was utilized to pre-concentrate and separate E2 in real samples (urine, blood, hospital wastewater, tap water). This method shows promise for efficient and selective removal of E2 from aqueous solutions.

The adsorption isotherm, thermodynamic parameter, and kinetics study for dyeing without mordanting cotton fabric dyed with natural dye obtained from an aqueous extract of the Scutellaria Orientalis were investigated using, as optimal conditions, at pH of 5 a material to liquor ratio (MLR) of 1:100, an initial dye concentration of 1.0/l and contact time (20–90 min.). The effect of the temperature and dyeing time (from 20–90 min.) on dyeing was evaluated using three different temperatures (from 60, 80, and 90°C). Also, the adsorption isotherms have been analyzed by Langmuir and Freundlich models. It is revealed that the adsorption kinetics was found to follow the pseudo-first-order kinetic model, the obtained adsorption isotherm was found to be suitable for both Langmuir and Freunlich adsorption isotherm, and the dyeing process is exothermic. The rate of dye uptake and thermodynamic parameters have also been calculated and discussed.

A study was conducted to investigate the efficiency of iron oxide nanoparticle (FeONPs) adsorption for removing of DOM in landfill leachate. FeONPs was directly prepared via sodium borohydride (KBH4) reduction method. Adsorption kinetics, isotherm and thermodynamic studies were developed to design the model for DOM removal. Pseudo first-order and pseudo second-order model have been studied to fit the experimental data. The regression results showed that the adsorption kinetics were more accurately represented by a pseudo second-order model. The Weber–Morris intraparticle diffusion model was used to analyze the adsorption kinetics data. The plot of qt versus t1/2 represents multi linearity, which showed that the adsorption processes occurred in more than one step. Adsorption isotherms were analyzed by Langmuir, Freundlich, Tempkin and Dubinin–Radushkevich, isotherms model. Equilibrium data were well fitted to the Dubinin– Radushkevich isotherm model. Maximum monolayer adsorption based on Langmuir was calculated to be 21.74 mg/g. Thermodynamic parameters such as free energy changes (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) were evaluated between temperatures of 25 °C and 40 °C. The ΔG° was noticed progressively decrease from -9.620 -9.820 -10.021, and -10.222 kJ/mol as the temperature increase. The ΔH° and ΔS° values were found to be 2.350 kJ/mol and 40.165 J/mol.K respectively. The results showed that the overall adsorption process was endothermic and spontaneous. The results from this study suggested that FeNPs could be a viable adsorbent in managing higher DOM problems associated with landfill leachate.

(Pyridine-2,5-diylbis(azaneylylidene)) bis-(methaneylylidene)) bis(benzene-5,1,3-triyl) tetrakis (hydrogen phosphonate) (PZMB) was successfully synthesized for Th(IV) and Ce(IV) adsorption, the adsorption parameters evaluated and found to be pH 3.5, time 60 min, dose 0.15 g. Adsorption kinetics, isotherm, and thermodynamics studies. Adsorption kinetics studies show that adsorbent follow pseudo-second-order model while isotherm studies conclude that adsorption processes fitted Langmuir and D-R isotherm model. The maximum adsorption capacity of BZMB of Th(IV) and Ce(IV) are 366.4 and 244.53 mg/g respectively, Thermodynamic studies indicate both adsorption processes exhibited by the PZMB were endothermic, spontaneous and sorption occurs in a random manner.