Pseudo-second Order Kinetic Equation Research Articles

Synthesis, characterization, and flocculation performance of cationic starch nanoparticles

A series of cationic starches with different degrees of substitution were synthesized by etherification of potato starch with 3-chloro-2-hydroxypropyl trimethylammonium chloride (CTA). Cationic starch nanoparticles (CTA-StNPs) with different sizes were prepared by precipitation. Flocculation behaviors of the CTA-StNPs in simulated water sample containing kaolin were studied. The results showed that the dosage required to bring the simulated water sample containing kaolin to attain maximum transmittance at pH = 4 was significantly less than that at pH = 7. Both the size and degree of substitution of the CTA-StNPs affected their flocculation performance. The smaller the size and the higher the degree of substitution of CTA-StNPs, the better was the flocculation performance. Charge neutralization played a leading role in the flocculation process. The adsorption process of the CTA-StNPs onto kaolin could be divided into rapid adsorption, stable adsorption and equilibrium adsorption and followed pseudo second-order kinetic equation very well (R2 > 0.99).

Removal of Lead Ions From Aqueous Solutions Using Melamine-Modified Nano Graphene Oxide

Today, due to the industrialization of societies, the existence of heavy metals has created many problems for humans, other organisms, and the environment. Lead (Pb) is highly toxic and the second most commonly used metal. The aim of this study was to evaluate the efficiency of melamine-modified nanographene oxide in the removal of Pb from aqueous media. To increase the efficiency of graphene oxide, it was mechanically converted to nano graphene oxide and melamine (4, 2 and 6-triazine, 3, 1 and 5 triamine). Experiments were performed at pH value of 3-8, temperature of 15-50°C, Pb concentration of 5-200 mg/g, adsorbent dose of 0.01-0.06 g, and contact time of 15- 150 minutes. The mechanism of the adsorption process was investigated using two Langmuir and Freundlich isotherm models, pseudo-first order and pseudo-second order kinetic equations, and thermodynamic equations. The results showed that the adsorption rate corresponds to the Freundlich isotherm model and pseudo-second order kinetic equation. Thermodynamic studies also showed that the adsorption process is associated with increasing irregularities and it is endothermic. In constant conditions (pH of 6, contact time of 60 minutes, ambient temperature of 22°C, Pb concentration of 20 mg/L, and adsorbent dose of 0.01 g), the adsorption capacity was 191.65 mg/g. The highest adsorption occurs at the concentration of 5 mg/L and the highest adsorption capacity and removal percentage was observed at a concentration of 200 mg/L, which were 1896.3 mg/g and 98.8%, respectively. Due to the high adsorption capacity, the adsorbent was able to remove lead from the contaminated environment.

A Novel Approach for Adsorption of Lead (II) Ions from Wastewater Using Cane Papyrus

Lead (II) ions are a very toxic element known to cause detrimental effects to human healtheven at very low concentrations. An adsorbent prepared using Cane Papyrus was used for theadsorption of lead (II) ion from aqueous solution. Batch experiments were performed onsimulated aqueous solutions under optimized conditions of adsorbent dosage, contact time, pHand initial lead (II) ion concentration at 25Co. The Freundlich isotherm model more suitablydescribed the adsorption process than the Langmuir model with linearized coefficients of 0.986and 0.9733, respectively. Pseudo-second order kinetic equation best described the kinetics of thereaction. Fourier transform infra-red analysis confirmed the presence of amino (–NH), carbonyl(–C=O) and hydroxyl (–OH) functional groups. Furthermore, 0.2M HCl was a better desorbingagent than 0.2 M NaOH and de-ionized water. The experimental data obtained demonstrated thatCane Papyrus can be used as a suitable adsorbent for lead (II) ions removal from wastewater.

Removal of Cu (II) by calcinated electroplating sludge

Electroplating sludge consists of various heavy metal oxides, which may be utilized as adsorbent to remove Cu (II) present in aqueous environment. This study evaluated the adsorption performance of calcinated electroplating sludge. The adsorption isotherm based on Langmuir equation proved that calcinated electroplating sludge had a higher adsorption performance than raw electroplating sludge, with maximum adsorption capacity 92 mg/g and 76.34 mg/g, respectively. Findings of the conducted kinetic study revealed that both surface adsorption and intra-particular diffusion were involved during the adsorption process. Moreover, the comparison between the experimental and calculated data of equilibrium adsorption capacity demonstrated that the pseudo second-order kinetic equation fitted well with 38.31 mg/g of calcinated sludge and 33.66 mg/g of raw sludge, approximate to real-world data. Furthermore, adsorption mechanism research demonstrated that while OH group plays a vital role in raw sample, Ca2+, in addition to OH group, was involved in ion exchange in calcinated sample.

Katyon Değişim Reçinesi Kullanarak Sulu Çözeltilerden Amonyum Giderimi

Ammonium is one of the main factors responsible for eutrophication of water bodies. Purolite SSTC60 ion exchange resin was used to investigate its potential use on ammonium removal efficiency. The effects of important parameters affecting ion exchange such as ion exchange resin dosage, initial solution pH, temperature, mixing speed and initial ammonium concentration on ammonium removal were investigated. The highest ammonium removal was achieved at pH 7. It was determined that ammonium removal rates increased with resin dosage, mixing speed and temperature increase. It has been determined that temperatures higher than 20°C and mixing speed do not have a significant effect on ammonium removal efficiencies at equilibrium. It was observed that removal efficiencies decreased with increasing initial ammonium concentrations. Pseudo-first order and pseudo-second order kinetic equations were analyzed using nonlinear method to determine the most appropriate kinetic model for ammonium ion removal and found to be compatible with the pseudo-first order kinetic model. Finally, the evaluation of experimental data using nonlinear forms of Langmuir and Freundlich isotherm models determined that the adsorption data fit the Freundlich isotherm model rather than the Langmiur isotherm model.

Adsorption Studies of Volatile Organic Compound (Naphthalene) from Aqueous Effluents: Chemical Activation Process Using Weak Lewis Acid, Equilibrium Kinetics and Isotherm Modelling

This study deals with the preparation of activated carbon (CDSP) from date seed powder (DSP) by chemical activation to eliminate polyaromatic hydrocarbon—PAHs (naphthalene—C10H8) from synthetic wastewater. The chemical activation process was carried out using a weak Lewis acid of zinc acetate dihydrate salt (Zn(CH3CO2)2·2H2O). The equilibrium isotherm and kinetics analysis was carried out using DSP and CDSP samples, and their performances were compared for the removal of a volatile organic compound—naphthalene (C10H8)—from synthetic aqueous effluents or wastewater. The equilibrium isotherm data was analyzed using the linear regression model of the Langmuir, Freundlich and Temkin equations. The R2 values for the Langmuir isotherm were 0.93 and 0.99 for naphthalene (C10H8) adsorption using DSP and CDSP, respectively. CDSP showed a higher equilibrium sorption capacity (qe) of 379.64 µg/g. DSP had an equilibrium sorption capacity of 369.06 µg/g for C10H8. The rate of reaction was estimated for C10H8 adsorption using a pseudo-first order, pseudo-second order and Elovich kinetic equation. The reaction mechanism for both the sorbents (CDSP and DSP) was studied using the intraparticle diffusion model. The equilibrium data was well-fitted with the pseudo-second order kinetics model showing the chemisorption nature of the equilibrium system. CDSP showed a higher sorption performance than DSP due to its higher BET surface area and carbon content. Physiochemical characterizations of the DSP and CDSP samples were carried out using the BET surface area analysis, Fourier-scanning microscopic analysis (FSEM), energy-dispersive X-ray (EDX) analysis and Fourier-transform spectroscopic analysis (FTIR). A thermogravimetric and ultimate analysis was also carried out to determine the carbon content in both the sorbents (DSP and CDSP) here. This study confirms the potential of DSP and CDSP to remove C10H8 from lab-scale synthetic wastewater.

Adsorption of Pb Ions from Oily Wastewater by Anthraquinone Modified Carbon Nanotube

The aim of this research was to investigate the adsorption properties of anthraquinone modified carbon nanotube (ACNT) in oily wastewaters containing Pb ions. The modified adsorbents were characterized using Fourier transform infra-red spectroscopy and SEM analysis. The adsorption and regeneration studies were conducted in batch mode using a Taguchi (L16) orthogonal array to optimize experimental runs. The controllable factors used in this study consisted of: pH of the solution (A); adsorbent dosage (B); adsorbent type (C); contact time (D); temperature (F). The effects of each factor were studied at four levels on the removal efficiency of metals from aqueous solution. Concentrations of metal ions were assessed by atomic absorption spectrometer. The total optimum adsorptive removal of lead ions was obtained with C0 = 10 mg•l-1, T = 338 K, pH = 6, m = 0.020 mg and t = 60 min. The Langmuir model was representative to simulate adsorption isotherms. The adsorption kinetics of Pb adsorption by ACNT was modeled using the pseudo-first order, the pseudo-second order, and intraparticle diffusion kinetics equations. The results indicate that the pseudo-second order kinetic equation and intraparticle diffusion model were adequate to describe the adsorption kinetics.

Nanocomposites of graphene and zirconia for adsorption of organic-arsenic drugs: Performances comparison and analysis of adsorption behavior

3-Nitro-4-hydroxy-phenylarsonic acid (3-NHPAA), an organic-arsenic compound, as one of widely used antibacterial veterinary drug, has greatly attracted the attention due to its potential threats on ecological environment. A series of the nanocomposites of zirconia nanoparticles with crystal phases (pure monoclinic, pure tetragonal and mixed phase (monoclinic + tetragonal)) anchored on reduced graphene oxide were produced through managing the concentration of triethanolamine solution and the reaction time. The effects of the crystal phases of the zirconia in the structure of the nanocomposites were played a key role in the adsorption performances of the 3-NHPAA. Experiment data identified the nanocomposites with monoclinic phase of zirconia excelled at the adsorption of the 3-NHPAA with a higher adsorption capacity up to 207.2 mg g−1. The uptake of the 3-NHPAA by the three nanocomposites was implemented within 60 min and highly pH-dependent which illustrated electrostatic attraction between them as a main mechanism during the adsorption process. A wider pH range (3.8–8.8) for the uptake of the 3-NHPAA by the nanocomposites with the monoclinic phase of zirconia was obtained compared with the nanocomposites containing tetragonal phase (3.8–5.9) or the mixed phase (3.8–7.1) of zirconia. The adsorption of the 3-NHPAA was well described by the pseudo-second order kinetic and Langmuir equations. The thermodynamic parameters suggested that the adsorption of the 3-NHPAA over the three nanocomposites was endothermic and spontaneous in nature. In summary, the nanocomposites of reduced graphene oxide and monoclinic phase of zirconia nanoparticles as an adsorbent were better to the adsorption of the 3-NHPAA.

Removal of Cr(VI) from wastewater by silver-loaded natural clinoptilolite

Presence of hexavalent chromium, Cr(VI), in water is an important environmental and human health problem. Natural zeolites are widely accepted as non-expensive adsorbents for sustainable remediation, however they are not effective in removing metals in anionic form. The paper presents study on use of silver (Ag) modified natural clinoptilolite to immobilize Cr(VI) ions from model and real neutral to slightly alkaline wastewater. Increasing the initial pollutant concentration increases the removed amount (80 % removal from model wastewater in 45 min at initial concentration of 30 mg Cr(VI)/L). The pseudo-second order kinetic equation best describes the Cr(VI) immobilization by the Ag-modified zeolite, which is indicative for the chemical nature of the rate-limiting step of the process. The data obtained are best fitted to the Freundlich adsorption isotherm. The Ag-modified clinoptilolite removes in 30 min over 80 % of Cr(VI), over 75 % of Cu(II) and over 70 % of Zn(II) that present simultaneously in an industrial wastewater. Due to its ability to remove Cr(VI) species, in combination with some heavy metal ions, some organic pollutants and exhibited antibacterial activity, silver loaded clinoptilolite seems to be a possible multifunctional reagent in the water and wastewater treatment and deserves further investigation.

Сорбционные взаимодействия в системе гидроксиапатит—водный раствор CuSO4

Regularities of adsorption of copper (II) ions by synthetic hydroxyapatite have been examined. It is shown that sorption of metal ions occurs mainly in the mixed diffusion region, the chemical interaction described by the pseudo-second order kinetic equation has a significant effect on the process speed. It was found out that that the adsorption isotherm was described by the Langmuir monomolecular adsorption equation in the best way. Interaction specificity of hydroxyapatite with water was studied by NMR relaxation spectroscopy method

Simulation on release of heavy metals Cd and Pb in sediments

Abstract The re-release process and the release rate of heavy metals, cadmium and plumbum, which are rich in sediments of a certain water area, were investigated using a combined experimental and numerical method. Results show that the release law of Cd and Pb in sediments is divided into two stages: rapid release and dynamic equilibrium, which is in great agreement with the pseudo second-order kinetic equation with a correlation coefficient R2 above 0.99. As the flow velocity accelerates, the release rate of heavy metals increases. The analysis results indicate that the water quality in the area can exceed the surface water Class V standard less than 3 h, and all but one of the relative deviations between the simulation value and the field survey result are within ±10%.

Adsorption modelling studies for the removal of Rose Bengal dye from aqueous solutions using a natural adsorbent perlite

Modelling studies for the adsorptive eradication of a dye Rose Bengal dye in aqueous solutions using an adsorbent perlite have been exploited. A batch mode adsorption technique was performed to find the influence of contact time, strength of the Rose bengal dye, dosage of the perlite, pH and temperature. The equilibrium of the adsorption has been achieved only after the contact time of 40 min. The kinetic behaviour of the adsorption has been evaluated using the pseudo first-order as well as the second-order types. The achieved kinetic equation statistics of pseudo second-order kinetic equation has a close proximity with unity. Equilibrium adsorption values are obtained from the Freundlich and Langmuir isotherm. From the correlation data, Freundlich isotherm remains suited to describe the adsorption behaviour of Rose bengal dye on the perlite. From the experimental data, the thermodynamic parameters like ∆Ho, ∆So, and ∆Go are assessed. The calculated result was shown that the adsorption behaviour is exothermic as well as immediate in description. The dimensionless separation factor has been shown that perlite is the substitute to other adsorbents for the elimination of rose Bengal dye from the aqueous solution.

Preparation of MIL-100 via a novel water-based heatless synthesis technique for the effective remediation of phenoxyacetic acid-based pesticide

An iron-based metal-organic framework (MOF), MIL-100(Fe) has been synthesized by a novel water-based heatless recipe. The physical-chemical qualities of MIL-100(Fe) were examined by X-ray diffraction, Field Emission Scanning Electron Microscopy, Nitrogen adsorption-desorption isotherm, Thermogravimetric Analysis and Fourier Transform Infrared Spectroscopy. With a high specific surface area of 1,893 m2/g, the crystalline MIL-100(Fe) exhibited an extraordinary performance for the adsorptive removal of 2,4-dichlorophenoxyacetic acid (2,4-D) pesticide from the aqueous solution under laboratory and on-site conditions. The adsorption equilibria have been simulated by the nonlinear Langmuir, Freundlich, Sips, Dubinin–Radushkevich, and Redlich–Peterson isotherm models, with a monolayer adsorption capacity for 2,4-D of 858 mg/g. The adsorption kinetics was rapid, with exceeding 50% of the adsorbate loading has been completed within the first 5 min of contact time, and best described by the pseudo-second order kinetic equation. Further analyses with the Bangham, Vermeulen, and intraparticle diffusion models concluded that intraparticle pore diffusion is the controlling mechanism, but it is not the sole rate-limiting step. MIL-100(Fe) retained the adsorptive performance in the 2,4-D loaded tap water and lakewater samples. The profound effects with solution pH and ionic strength on the adsorptive uptake suggested that the prevailing interaction was the electrostatic attraction between the deprotonated 2,4-D and positive-charged MIL-100(Fe). The adsorption process was spontaneous with favorable enthalpy and entropy changes as the thermodynamic driving force. Water stability test illustrated negligible iron leaching from the Fe-MOF. MIL-100(Fe) adsorbent could be reused for at least 5 times, with minor deterioration in the adsorptive uptake via simple solvent stripping. The high adsorptive potential and well-developed porosity, supported by the sustainable preparation methodology, rendered MIL-100(Fe) a promising adsorbent for the effective decontamination of water pollutants.

A characteristic study of Zea mays L. (sweet corn) cobs for synthetic dye degradation from aqueous media.

The current study reports a systematic methodology of Zea mays L. (sweet corn) cobs (ZMLC) for the sequestration of synthetic dye (gentian violet) from aqueous solutions. Adsorbent was scrutinized by using scanning electron microscopy, Fourier transform infra-red spectrometry with pHpzc determination. The impact of various adsorption parameters including pH effect, ZMLC (sorbent) dosage, temperature, concentration and shaking time was examined. The equilibrium sorption isotherms were determined by the batch method from 283 to 303 K at pHpzc. Adsorption data were adjusted to four isothermal models: Langmuir, Freundlich, Dubinin-Radushkevich and Temkin's models, which presented the best adjustment to Freundlich, Dubinin-Radushkevich and Temkin's at 283 K. The kinetic profile fitted well to the pseudo-second order kinetic equation at three distinct concentrations 600, 700, 800 mg/L. Maximum sorption capacity was gained up to 700 mg.g-1 for gentian violet at pH 3, respectively. The adsorption process is endothermic, non-spontaneous, favorable thermodynamically due to positive values of entropy and Gibbs free energy and randomness decreases during the adsorption process. Furthermore, after biosorption onto ZMLC the dye can be desorbed effectively by using mineral base KOH solution. Consequently, the ZMLC is said to be a promising biosorbent to remediate gentian violet-contaminated water as well as wastewater.

Preparation of novel chitosan polymeric nanocomposite as an efficient material for the removal of Acid Blue 25 from aqueous environment

A novel, sustainable chitosan polymeric nanocomposite (CS-PVA@CuO) was synthesized and subjected to the removal of acid blue 25 (AB25) from the aqueous environment. The influence of different variables such as pH, contact time, initial dye concentration, temperature, and adsorption kinetics has been examined in the batch adsorption process. The CS-PVA@CuO composite was systematically characterized by XRD, FTIR, SEM, and EDX analysis. The pseudo-first order (PFO), pseudo-second order (PSO), and intra-particle diffusion kinetics equations were used to examine the kinetic data of the adsorption process. The adsorption kinetics confirms that the PSO model was a more exact fit. Thermodynamics study typically revealed that the uptake of AB25 by the adsorbent is spontaneous and endothermic in nature. Remarkably, the results reveal the highest adsorption capacity of the CS-PVA@CuO was 171.4 mg/g at 313 K. To be specific, CS-PVA@CuO polymer nanocomposite can be effectively used as a suitable adsorbent material for the potential elimination of anionic AB25 dye from the aqueous solutions.

One step acid activation of bentonite derived adsorbent for the effective remediation of the new generation of industrial pesticides

Herein, the facile one step acid activation of bentonite derived functionalized adsorbent (AB) for the effective remediation of both ionic and non-ionic secondary pesticides, ametryn and metolachlor has been attempted. The surface characteristics of AB were examined by the nitrogen adsorption–desorption analysis, scanning electron microscopy (SEM), and Fourier Transforms Infrared (FTIR) Spectroscopy. The adsorptive behavior was evaluated with respect to the effect of contact time, initial concentrations and solution pH. The equilibrium data were fitted to the Langmuir, Freundlich and Temkin isotherm models, while the adsorption kinetic was analyzed using the pseudo-first order and pseudo-second order kinetic equations. Thermodynamic parameters including the standard enthalpy change (ΔH°), standard entropy change (ΔS°), and Gibbs free energy change (ΔG°) were established. Thermodynamic analysis illustrated that the adsorption process was feasible and exothermic in nature, while the characterization findings verified the alteration of FTIR bands, and a high specific surface area of 464.92 m2/g, with a series of pores distributed over the surface. Equilibrium data was best confronted to the pseudo-second order kinetic model, while the adsorptive removal of ametryn and metolachlor onto AB was satisfactory described by the Langmuir isotherm model, with the monolayer adsorption capacities for ametryn and metolachlor of 2.032 and 0.208 mmole/g respectively. The findings outlined the potential of the newly develop AB for the on-site treatment of pesticide polluted water.

Hierarchical porous boron nitride with boron vacancies for improved adsorption performance to antibiotics

Designing atomically defective adsorbents with high specific surface area has emerged as a promising approach to improve sorption properties. Herein, hierarchical porous boron nitride nanosheets with boron vacancies (Bv-BNNSs) were in-situ synthesized via a one-step ZnCl2-assisted strategy. Being benefitted from the dual-functional template of zinc salt, highly-active boron vacancies and abundant hierarchical pores were simultaneously generated in the Bv-BNNSs framework. By employing the boron vacancies engineering strategy, the morphological and electronic structures were controllably tuned. Meanwhile, the specific surface area was improved to as high as 1104 m2/g. Owning to the abundance of accessible surface active-sites, the sorption capacity to antibiotic tetracycline (TC) on Bv-BNNSs was boosted by 38% compared to the pristine boron nitride nanosheets (BNNSs). Detailed fitting results showed that TC sorption on Bv-BNNSs obeyed the pseudo-second order kinetic equation and the Freundlich isotherm model. The pi − pi interaction with a multi-layered stacking form was proposed as the dominated sorption mechanism. Furthermore, DFT calculations verified that the interaction energy between Bv-BNNSs and TC was enhanced. The high activity, excellent selectivity, and remarkable durability of the Bv-BNNSs nanomaterial suggest the great potential in practical wastewater treatment.

Preparation of an environmentally friendly lead adsorbent. A contribution to the rational design of heavy metal adsorbents

Abstract This work described the preparation and characterization of water insoluble chitosan derivatives as lead adsorbents. In highly regioselective reactions, N-substituted crosslinked chitosan derivatives were obtained by crosslinking native chitosan with mucic and adipic acid (a polyhydroxylated and a non-functionalized diacid of the same length chains). The crosslinking degree of the chitosan modified with adipic acid was significantly higher than that crosslinked with mucic acid (0.446 and 0.316, respectively), while the degree of substitution was almost the same (approximately 80 %). Lead adsorption isotherms were constructed at different temperatures and adjusted to well-known models, obtaining the best fit to the experimental data with Langmuir model. The lead adsorption capacity of new materials was greater than many of the adsorbents described in literature (76.3 and 69.7 mg g−1 for chitosan modified with mucic and adipic acid, respectively). Moreover, thermodynamic parameters were calculated, and results showed that the lead adsorption on the derivatives was spontaneous, exothermic, and governed by chemical interaction. Besides, kinetic studies were performed and adjusted to well-known models. The pseudo-second order kinetic equation was the one that most appropriately described the lead adsorption on the new materials. Results were consistent with the strong electrostatic attraction established between the lead cations and the free carboxylate groups of the derivatives.

Fabrication of a porous chitosan/poly-(γ-glutamic acid) hydrogel with a high absorption capacity by electrostatic contacts

A porous chitosan (CS)/poly-(γ-glutamic acid) (γ-PGA) hydrogel was prepared by polymerization by electrostatic contacts of CS with γ-PGA without linker. The porosity of the hydrogel remarkably depends on γ-PGA content, pH regulator, and drying way. The optimization of them had given the hydrogel a high swelling capacity of 1398%, 11-fold higher than that of neat CS hydrogel. The hydrogel was applied to recover bovine serum albumin (BSA) from aqueous solution, and its adsorption capacity was influenced by the initial concentration and pH of BSA solution. Based on the studies of kinetics and isotherm, a high equilibrium adsorption capacity (qe = 948 mg/g) and a correlation coefficient of 0.996 were calculated from pseudo-second order kinetic equation, and a high affinitive constant (kF = 472 mL/mg) and a high saturated absorption capacity (qm = 1818.5 mg/g) were observed from Freundlich isotherm equation, indicating the porous hydrogel will be a good absorbent for protein recovery from sewage.

Modified pineapple bran cellulose by potassium permanganate as a copper ion adsorbent and its adsorption kinetic and adsorption thermodynamic

Using potassium permanganate-modified pineapple cellulose as an adsorbent, the absorption behaviour of Cu2+ was analyzed based on isothermal adsorption, adsorption kinetics and adsorption thermodynamics. SEM, FTIR and XPS analyses were conducted to further investigate the absorption mechanism. Results showed that the modified pineapple bran cellulose by potassium permanganate adsorbed more Cu2+ in solution than the unmodified pineapple bran cellulose by 110.96%. SEM, XPS and FTIR analyses demonstrated that the strong oxidizing agent MnO4− attacked the molecule chains of pineapple bran cellulose and resulted in the growth in the specific surface area and active groups, which provided additional adsorption sites for Cu2+. Adsorption kinetic studies revealed that the adsorption of the modified pineapple bran cellulose for Cu2+ was consistent with the Freundlich isotherm and the pseudo-second order kinetic equation indicating mainly chemisorption. Thermodynamic studies showed that the adsorption process was spontaneous and exothermic. And the chemisorption process dominated the Cu2+ adsorption process of modified pineapple bran cellulose.