Removal of methylene blue dye from aqueous solution by adsorption onto sodium humate/polyacrylamide/clay hybrid hydrogels

A type of novel hybrid hydrogels from sodium humate (SH), polyacrylamide (PAM), and hydrophilic laponite clay were prepared using potassium persulfate (KPS) as the initiator and N,N'-methylenebisacrylamide (MBA) as the cross-linker. The morphology of the hydrogels was characterized by field emission scanning electron microscope (FESEM). The adsorption-desorption kinetics of methylene blue (MB) were also investigated. It was shown that SH/PAM/clay hydrogels exhibited excellent performance in MB adsorption. The maximum absorption concentration of MB was 800 mg/l/g of hydrogel. The adsorption concentration of hydrogels increased with increasing SH or clay content. Less MB were desorbed with increasing SH content, while the clay content had no significant influence on the amount of MB desorbed. This effect was attributed to the formation of a ionic complex between the imine groups of MB and the ionized carboxylic groups of SH. MB diffusion process was dominant in MB desorption.     

Mechanisms controlling the temperature-dependent binding of proteins to poly(N-isopropylacrylamide) microgels

Poly(N-isopropylacrylamide) (PNIPA) microgels may offer several advantages over PNIPA-modified surfaces when used as sorbents in temperature-sensitive chromatography. Yet, a full exploitation of these advantages requires a better understanding of the mechanisms controlling the separation process. As a model system, we have studied the binding of three proteins (bovine serum albumin (BSA), ovalbumin, and lysozyme) to PNIPA microgels. Binding experiments were conducted both below (25 degrees C) and above (37 degrees C) the volume phase transition temperature of the gel, T(c). The analysis of the binding isotherms has shown that although an average gel particle contained a larger amount of protein below the phase transition temperature, the concentration of the protein within the particle was higher above this temperature. These findings were attributed to changes in the binding loci due to temperature swings around T(c): whereas a sorption mechanism is dominant below this temperature, surface-adsorption was more important above it. A comparison between the three studied proteins has shown that below T(c) the binding increases with a decrease in the molecular weight. On the other hand, no significant difference in the bound protein amounts was observed above the phase transition temperature. Our results imply that, despite the increase in the gel's hydrophobicity above the phase transition temperature, the resolution in bioseparations based on PNIPA gels is not necessarily better above T(c).     

Control of cell cultivation and cell sheet detachment on the surface of polymer/clay nanocomposite hydrogels

Cell cultivation on the surface of a novel poly(N-isopropylacrylamide) (PNIPA) hydrogel (N-NC gel), consisting of a specific type of organic (PNIPA)/inorganic (clay) network, was studied using three cell types; HepG2 human hepatoma cells, human dermal fibroblasts, and human umbilical vein endothelial cells. For the first time, it was found that cells could be cultured to be confluent on the surfaces of PNIPA hydrogels using N-NC gels, regardless of gel thickness. Cell adhesion and proliferation on N-NC gels exhibit strong dependencies on clay concentration (C(clay)), and the numbers of cultured cells are maximum at about C(clay) = 6 x 10(-2) mol (45.72 g)/1 L of H(2)O. On the contrary, it was almost impossible to culture cells on conventional, chemically crosslinked PNIPA hydrogels, regardless of their cross-linker concentration. The reasons why cells cultured only on the surfaces of N-NC gels with their specific network structure and composition were discussed in terms of water content, protein adsorption, surface flatness, hydrophobicity of dehydrated PNIPA chains, and the anionic charge on exfoliated clay. Finally, it was found that cells cultured on the surfaces of N-NC gels could be detached in the forms of sheets of cells without trypsin treatment, but by just decreasing the temperature to 20 degrees C.     

A sustainable process for adsorptive removal of methylene blue onto a food grade mucilage: kinetics,thermodynamics, and equilibrium evaluation

Abstract

Adsorption of dyes onto natural materials like polysaccharides is considered a green chemistry approach for remediation of wastewater. In this work, the polysaccharide isolated from the corm of Colocasia esculenta (L.) Schott or taro tuber (CEM) was utilized for removing methylene blue (MB) from aqueous solution by batch adsorption method. The CEM adsorbent was characterized by FTIR spectroscopy, Brunauer–Emmett–Teller (BET), and scanning electron microscopy (SEM). The solution pH and adsorbent dose have been found to have a significant positive correlation with the adsorptive removal efficiency of CEM for MB dye. The removal efficiency of CEM was found to be 72.35% under the optimum conditions; 20?mg/L initial concentration of dye, 120?mg of adsorbent dose, solution pH 8.5, 311.2?K temperature and 80?min contact time. The adsorption of MB onto CEM followed best the Freundlich isotherm and pseudo-second-order kinetics. The adsorption was thermodynamically favorable and was endothermic in nature. The desorption/adsorption data justifiably indicated the reuse capability of CEM adsorbent for MB adsorption. Hence, CEM may be regarded as an eco-friendly and cost-effective natural adsorbent for MB dye removal from aqueous solution.     

Basic dye adsorption onto an agro-based waste material--sesame hull (Sesamum indicum L.)

The aim of this project was to establish an economical and environmentally benign biotechnology for removing methylene blue (MB) from wastewater. The adsorption process of MB onto abandoned sesame hull (Sesamum indicum L.) (SH) was investigated in a batch system. The results showed that a wide range of pH (3.54-10.50) was favorable for the adsorption of MB onto SH. The Langmuir model displayed the best fit for the isothermal data. The exothermic adsorption process fits a pseudo-second-order kinetic model. The maximum monolayer adsorption capacity (359.88 mg g(-1)) was higher than most previously investigated low-cost bioadsorbents (e.g., peanut hull, wheat straw, etc.). This study indicated that sesame hull is a promising, unconventional, affordable and environmentally friendly bio-measure that is easily deployed for removing high levels of MB from wastewater.     

Poly(N-isopropylacrylamide)-based semi-interpenetrating polymer networks for tissue engineering applications. 1. Effects of linear poly(acrylic acid) chains on phase behavior

Poly(N-isopropylacrylamide)-based [P(NIPAAm)-based] semi-interpenetrating polymer networks (semi-IPNs), consisting of P(NIPAAm)-based hydrogels and linear poly(acrylic acid) [P(AAc)] chains, were synthesized, and the effects of the P(AAc) chains on semi-IPN injectability and phase behavior were analyzed. In P(NIPAAm)- and P(NIPAAm-co-AAc)-based semi-IPN studies, numerous reaction conditions were varied, and the effects of these factors on semi-IPN injectability, transparency, phase transition, lower critical solution temperature (LCST), and volume change were examined. The P(AAc) chains did not significantly affect the LCST or volume change of the semi-IPNs, compared to control hydrogels. However, the P(AAc) chains affected the injectability, transparency, and phase transition of the matrices, and these effects were dependent on chain amount and molecular weight (MW) and on interactions between the P(AAc) chains and the solvent and/or copolymer chains in P(NIPAAm-co-AAc) hydrogels. These results can be used to design "tailored" P(NIPAAm)-based semi-IPNs that have the potential to serve as functional scaffolds in tissue engineering applications.     

Controllable Stabilization of Poly(N-isopropylacrylamide)-Based Microgel Films through Biomimetic Mineralization of Calcium Carbonate

Two types of thermoresponsive microgels, poly(N-isopropylacrylamide) (PNIPAM) microgels and poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAMAC) microgels were synthesized and used as templates for the mineralization of amorphous calcium carbonate (ACC) by diffusion of CO(2) vapor under ambient conditions. Thermosensitive PNIPAM/CaCO(3) hybrid macroscopic hydrogels and micrometer-sized PNIPAMAC/CaCO(3) hybrid microgels were controllably obtained and different mineralization mechanistic processes were proposed. The impact of the loaded CaCO(3) on the size, morphology, stability, and thermosensitivity of the microgels was also analyzed. PNIPAM/CaCO(3) hybrid macrogels had a slight decrease in thermoresponsive phase transition temperature, while PNIPAMAC/CaCO(3) hybrid microgels showed a clear increase in phase transition temperature. The difference reflected different amount and location of ACC in the gel network, causing different interactions with polymer chains. The PNIPAMAC/CaCO(3) microgels formed stable monolayer films on bare silica wafers and glass coverslips upon drying. The microgel films could facilitate the attachment and growth of 3T3 fibroblast cells and their subsequent detachment upon temperature drop from 37 °C to the ambient condition around 20 °C, thus, offering a convenient procedure for cell harvesting.     

择伐干扰对小兴安岭阔叶红松林土壤磷吸附解吸的影响

以小兴安岭地区阔叶红松林经过轻度、中度和强度择伐干扰后形成的天然林以及未经干扰的原始林(对照)林地表层(0～10 cm)土壤为对象,对土壤磷素的最大吸附量、吸附强度、最大缓冲容量、最大解吸量、平均解吸率和易解吸磷量等指标进行测定,研究不同干扰强度导致土壤磷吸附解吸的规律性变化,分析择伐干扰对阔叶红松林土壤磷吸附解吸特征的影响.结果表明: 各林地土壤磷最大吸附量为1383.93～1833.34 mg·kg^-1,中度和强度干扰林地显著高于轻度干扰林地和原始林地;磷吸附强度为0.024～0.059 L·mg^-1,强度和轻度干扰显著增加了林地土壤磷吸附强度;最大缓冲容量为35.68～97.97 L·kg^-1,强度干扰林地土壤的最大缓冲容量最高.择伐干扰显著降低了林地土壤的供磷潜力.各样地土壤磷最大解吸量、平均解吸率和易解吸磷量分别为526.32～797.54 mg·kg^-1、14.7%～25.5%和1.79～5.41 mg·kg^-1,林地土壤磷素释放能力随干扰强度的增加显著降低.择伐干扰通过降低林地土壤磷的供应及释放能力改变了阔叶红松林土壤磷吸附与解吸特征.     

Controlled thermoresponsive hydrogels by stereocomplexed PLA-PEG-PLA prepared via hybrid micelles of pre-mixed copolymers with different PEG lengths

The stereocomplexed hydrogels derived from the micelle mixture of two enantiomeric triblock copolymers, PLLA-PEG-PLLA and PDLA-PEG-PDLA, reported in 2001 exhibited sol-to-gel transition at approximately body temperature upon heating. However, the showed poor storage modulus (ca. 1000 Pa) determined their insufficiency as injectable implant biomaterials for many applications. In this study, the mechanical property of these hydrogels was significantly improved by the modifications of molecular weights and micelle structure. Co-micelles composed of block copolymers with two sizes of PEG block length were shown to possess unique and dissimilar properties from the micelles composed of single-sized block copolymers. The stereomixture of PLA-PEG-PLA comicelles showed a controllable sol-to-gel transition at a wide temperature range of 4 and 80 °C. The sol-gel phase diagram displays a linear relationship of temperature versus copolymer composition; hence, a transition at body temperature can be readily achieved by adjusting the mixed copolymer ratio. The resulting thermoresponsive hydrogels exhibit a storage modulus notably higher (ca. 6000 Pa) than that of previously reported hydrogels. As a physical network solely governed by self-reorganization of micelles, followed by stereocomplexation, this unique system offers practical, safe, and simple implantable biomaterials.     

pH响应型蔗渣木质素水凝胶的制备及其对蛋白质的控释性能

该研究以蔗渣木质素和甲基丙烯酸为原料合成了pH敏感型蔗渣木质素/聚甲基丙烯酸水凝胶,对其合成条件、pH敏感性、溶胀-退溶胀性能以及对牛血清蛋白的控释等性质进行研究,并采用红外光谱、扫描电镜等对凝胶进行表征。结果表明:(1)对凝胶溶胀比影响的因素由大到小依次为甲基丙烯酸用量、交联剂用量、催化剂用量、反应的温度、木质素用量。当甲基丙烯酸单体浓度为1.75 mol·L~(-1)、木质素浓度为25 g·L~(-1)、交联剂浓度为3.25×10~(-2)mol·L~(-1)、引发剂浓度为1.25×10~(-2)mol·L~(-1)、反应温度为65℃时,所得水凝胶在模拟肠液中的溶胀比最大(28.16 g·g~(-1))。与不加木质素的聚甲基丙烯酸水凝胶相比,蔗渣木质素/聚甲基丙烯酸水凝胶的溶胀比有所下降,但其敏感pH由4~5碱移至6~8。(2)蔗渣木质素/聚甲基丙烯酸水凝胶的溶胀—退溶胀可逆性受组成的影响较大,但相对于聚甲基丙烯酸水凝胶,蔗渣木质素/聚甲基丙烯酸水凝胶对pH值的敏感响应性更强、响应速率更快,同时能在更短时间内达到溶胀平衡。(3)加入木质素可以提高水凝胶对牛血清蛋白的负载量,所试验的蔗渣木质素/聚甲基丙烯酸水凝胶样品对牛血清蛋白的最大负载量可达577 mg·g~(-1)。(4)牛血清蛋白在12 h后基本可达释放平衡;在模拟胃液中,牛血清蛋白的释放率仅10%,而在模拟肠液中释放率达92%。pH响应型蔗渣木质素/聚甲基丙烯酸水凝胶可以作为口服型蛋白类药物的潜在载体。     

Adsorption of methylene blue dye from aqueous solution by sugar extracted spent rice biomass

This study was aimed at using sugar extracted spent rice biomass (SRB) as a potential adsorbent to remove methylene blue (MB) dye from aqueous solution. The SRB was used without any modification. A three factor full factorial experimental design (2(3)) was employed to investigate the effect of factors (adsorbent dose, dye concentration, temperature) and their interaction on the adsorption capacity and color removal. Two levels for each factor were used; adsorbent dose (0.25-0.5g/100mL), dye concentration (25-50mg/L), and temperature (25-45°C). Initial dye concentration and adsorbent dosage were found as significant factors for the adsorption of MB dye. Langmuir isotherm (R(2)>0.998) best explained the equilibrium of MB adsorption on SRB with monolayer adsorption capacity of 8.13mg/g. The pseudo-second order model (R(2)>0.999) was best fitted to explain the adsorption kinetics. Thermodynamic investigation revealed that the adsorption process was spontaneous, endothermic, and was feasible to treat dyeing wastewater.     

Synthesis and characterization of magnetic β-cyclodextrin-chitosan nanoparticles as nano-adsorbents for removal of methyl blue

A novel nano-adsorbent, β-cyclodextrin-chitosan (CDC) modified Fe(3)O(4) nanoparticles (CDCM) is fabricated for removal of methyl blue (MB) from aqueous solution by grafting CDC onto the magnetite surface. The characteristics results of FTIR, SEM and XRD show that CDC is grafted onto Fe(3)O(4) nanoparticles. The grafted CDC on the Fe(3)O(4) nanoparticles contributes to an enhancement of the adsorption capacity because of the strong abilities of CDCM, which includes the multiple hydroxyl, carboxyl groups, amino groups and the formation of an inclusion complex due to the β-CD molecules through host-guest interactions, to adsorb MB. The adsorption of MB onto CDCM is found to be dependent on pH and temperature. Adsorption equilibrium is achieved in 50 min and the adsorption kinetics of MB is found to follow a pseudo-second-order kinetic model. Equilibrium data for MB adsorption are fitted well by Langmuir isotherm model. The maximum adsorption capacity for MB is estimated to be 2.78 g/g at 30°C. The CDCM was stable and easily recovered. Moreover the adsorption capacity was about 90% of the initial saturation adsorption capacity after being used four times.     

The effect of bacteriorhodopsin, detergent and hydration on the cubic-to-lamellar phase transition in the monoolein-distearoyl phosphatidyl glycerol-water system

The cubic phase of monoolein (MO) has successfully been used for crystallization of membrane proteins. It is likely that the transition to a lamellar phase upon dehydration is important for the crystallization process, and that the internal dimensions of the lipid phases (i.e., water pore diameter) are crucial for the inclusion and the diffusion of membrane proteins. In the present study, we investigated the cubic-to-lamellar phase transitions in the MO-water and the MO-distearoyl phosphatidyl glycerol (DSPG) systems. The MO-water system was investigated by means of isothermal sorption and desorption microcalorimetry. We show that the transition from cubic to lamellar phase induced by desorption is driven by entropy. At 25 degrees C, this occurs at a water activity of 0.98 with a transition enthalpy of 860 J/mol (MO). The phase behavior was also investigated in the presence of a small amount of the transmembrane protein bacteriorhodopsin (bR), and a detergent, octyl glucoside (OG), and it was shown that both bR and OG stabilize the lamellar phase. Analogous results were obtained for the MO-DSPG-water system. The latter system resembles the MO-water system in that a cubic-to-lamellar phase transition is induced by dehydration, although the structural properties of these phases are slightly different. Finally, we demonstrate that bR can be crystallized from a cubic phase of MO-DSPG-buffer.     

The use of immobilized Saccharomyces cerevisiae on radiation crosslinked acrylamide–maleic acid hydrogel carriers for production of ethyl alcohol

Radiation crosslinked acrylamide/maleic acid (AAm/MA) copolymers were prepared by γ-irradiation. They were used in experiments on swelling, diffusion, and immobilization of yeast cells (Saccharomyces cerevisiae) for the production of ethyl alcohol. AAm/MA hydrogels containing different amount of MA, irradiated at different doses, were used for swelling and diffusion studies. The parameters of swelling, diffusional exponents, network constants, diffusion coefficients and percent porosity of the hydrogel/penetrant systems were calculated and evaluated. Yeast cells were immobilized on to the hydrogels by adsorption during multiplication, and ethyl alcohol production by the hydrogels was investigated. Swelling of AAm/MA increased with increase in MA content. Ethyl alcohol production also increased with increasing MA in the hydrogels but decreased with an increase of irradiation dose.     

Adsorption of methylene blue using green pea peels (Pisum sativum): A cost-effective option for dye-based wastewater treatment

Methylene blue (MB), a common toxic dye, is largely discharged from dyeing processes for acrylic, nylon, silk, and woolen fabrics in textile industries. While application of conventional removal processes like chemical precipitation, ion exchange, commercial activated carbon adsorption, etc often become cost-prohibitive, the adsorption of MB by abundantly available green pea peel (GPP: Pisum sativum) derived and acid-treated carbon (GPP-AC) has proved to be a cost-attractive option in the present study. The physicochemical and morphological characteristics of GPP-AC were examined with the help of XRD, BET surface area, SEM, and Fourier transform infrared spectrophotometry ((FT-IR) analysis. The influences of such adsorption parameters as initial dye concentration, pH, contact time, adsorbent dosage, agitation speed, particle size, and temperature were evaluated and optimized. The equilibrium contact time for maximum adsorption of MB on to GPPAC was found to be 7 h. The equilibrium data of the adsorption process were modeled by using the Langmuir, Freundlich, Temkin, and Dubinin-Raduskevich (D-R) isotherms. However, the adsorption equilibrium data were best described by the Langmuir Isotherm model, with a maximum adsorption capacity of 163.94 mg MB/g GPPAC at 30°C.     

Synthesis and characterization of injectable poly(N-isopropylacrylamide-co-acrylic acid) hydrogels with proteolytically degradable cross-links

Hydrogels composed of N-isopropylacrylamide (NIPAAm) and acrylic acid (AAc) were prepared by redox polymerization with peptide cross-linkers to create an artificial extracellular matrix (ECM) amenable for testing hypotheses regarding cell proliferation and migration in three dimensions. Peptide degradable cross-linkers were synthesized by the acrylation of the amine groups of glutamine and lysine residues within peptide sequences potentially cleavable by matrix metalloproteinases synthesized by mammalian cells (e.g., osteoblasts). With the peptide cross-linker, loosely cross-linked poly(N-isopropylacrylamide-co-acrylic acid) [P(NIPAAm-co-AAc)] hydrogels were prepared, and their phase transition behavior, lower critical solution temperature (LCST), water content, and enzymatic degradation properties were investigated. The peptide-cross-linked P(NIPAAm-co-AAc) hydrogels were pliable and fluidlike at room temperature and could be injected through a small-diameter aperture. The LCST of peptide-cross-linked hydrogel was influenced by the monomer ratio of NIPAAm/AAc but not by cross-linking density within the polymer network. A peptide-cross-linked hydrogel with a 97/3 molar ratio of NIPAAm/AAc exhibited a LCST of approximately 34.5 degrees C. Swelling was influenced by NIPAAm/AAc monomer ratio, cross-linking density, and swelling media; however, all hydrogels maintained more than 90% water even at 37 degrees C. In enzymatic degradation studies, breakdown of the peptide-cross-linked P(NIPAAm-co-AAc) hydrogels was dependent on both the concentration of collagenase and the cross-linking density. These results suggest that peptide-cross-linked P(NIPAAm-co-AAc) hydrogels can be tailored to create environmentally-responsive artificial extracellular matrixes that are degraded by proteases.     

Adsorption and Desorption of Nickel(II) Ions from Aqueous Solution by a Lignocellulose/Montmorillonite Nanocomposite

A new and inexpensive lignocellulose/montmorillonite (LNC/MMT) nanocomposite was prepared by a chemical intercalation of LNC into MMT and was subsequently investigated as an adsorbent in batch systems for the adsorption-desorption of Ni(II) ions in an aqueous solution. The optimum conditions for the Ni(II) ion adsorption capacity of the LNC/MMT nanocomposite were studied in detail by varying parameters such as the initial Ni(II) concentration, the solution pH value, the adsorption temperature and time. The results indicated that the maximum adsorption capacity of Ni(II) reached 94.86 mg/g at an initial Ni(II) concentration of 0.0032 mol/L, a solution pH of 6.8, an adsorption temperature of 70°C, and adsorption time of 40 min. The represented adsorption kinetics model exhibited good agreement between the experimental data and the pseudo-second-order kinetic model. The Langmuir isotherm equation best fit the experimental data. The structure of the LNC/MMT nanocomposite was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), whereas the adsorption mechanism was discussed in combination with the results obtained from scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy analyses (FTIR). The desorption capacity of the LNC/MMT nanocomposite depended on parameters such as HNO₃ concentration, desorption temperature, and desorption time. The satisfactory desorption capacity of 81.34 mg/g was obtained at a HNO₃ concentration, desorption temperature, and desorption time of 0.2 mol/L, 60 ºC, and 30 min, respectively. The regeneration studies showed that the adsorption capacity of the LNC/MMT nanocomposite was consistent for five cycles without any appreciable loss in the batch process and confirmed that the LNC/MMT nanocomposite was reusable. The overall study revealed that the LNC/MMT nanocomposite functioned as an effective adsorbent in the detoxification of Ni(II)-contaminated wastewater.     

One-step synthesis of interpenetrating network hydrogels: Environment sensitivities and drug delivery properties

A novel interpenetrating network hydrogel for drug controlled release, composed of modified poly(aspartic acid) (KPAsp) and carboxymethyl chitosan (CMCTS), was prepared in aqueous system. The surface morphology and composition of hydrogels were characterized by SEM and FTIR. The swelling properties of KPAsp, KPAsp/CMCTS semi-IPN and KPAsp/CMCTS IPN hydrogels were investigated and the swelling dynamics of the hydrogels was analyzed based on the Fickian equation. The pH, temperature and salt sensitivities of hydrogels were further studied, and the prepared hydrogels showed extremely sensitive properties to pH, temperature, the ionic salts kinds and concentration. The results of controlled drug release behaviors of the hydrogels revealed that the introduction of IPN observably improved the drug release properties of hydrogels, the release rate of drug from hydrogels can be controlled by the structure of the hydrogels and pH value of the external environment, a relative large amount of drug released was preferred under simulated intestinal fluid. These results illustrated high potential of the KPAsp/CMCTS IPN hydrogels for application as drug carriers.     

Functionalization of pine needles by carboxymethylation and network formation for use as supports in the adsorption of Cr

Pine needles and their carboxymethyl forms were functionalized by network formation with 2-acrylamido-2-methylpropanesulphonic acid (AAmPSA) in the presence of N,N-methylene bisacrylamide. N-Tetramethylethylene diamine and ammonium persulfate were used as accelerator-initiator systems to prepare these hydrogels. The hydrogels were characterized by FTIR, SEM, and nitrogen analysis and for water uptake capacities before and after metal ion sorption with a view to evaluating their use in the removal of toxic ionic species from waste water. A detailed study of Cr⁶⁺ adsorption was carried out as a function of time, temperature, pH, and ionic strength. The thermodynamic parameters of adsorption such as ΔH⁰, ΔS⁰, and ΔG⁰ have been evaluated to understand the underlying mechanism of adsorption. In order to understand their reusability in possible technological applications, biodegradability of these hydrogels and their precursors was studied.     

Recovery of Acinetobacter radioresistens lipase by hydrophobic adsorption to n-hexadecane coated on nonwoven fabric

A simple and clean adsorption/desorption process was proposed for recovering Acinetobacter radioresistens lipase from fermentation broth. The adsorbent used was n-hexadecane coated on a hydrophobic nonwoven fabric (NWF). n-Hexadecane has a melting point of 16-18 degrees C, and its affinity for lipase decreases markedly from liquid to solid state. Accordingly, performing the adsorption and desorption above and below, respectively, the melting point would need no extraneous materials for separation. The adsorption isotherms at various temperatures were found to follow the Langmuir model. Simulation of the batch adsorption/desorption process showed that there exists an optimal amount of adsorbent for both concentration factor and enzyme recovery; the process is restrained by equilibrium. The performance of column adsorption/desorption could also be simulated using the adsorption isotherm, and it was shown that the concentration factor was proportional to the amount of adsorbent used. The benefits of this process include easy preparation of adsorbent, low operational cost, no extraneous materials needed, negligible enzyme denaturation, high efficiency, and simple process simulation.