Competitive Adsorption Phenomenon Research Articles

The role of coordinating anions in the supporting electrolyte during the electrocatalytic oxidation of glycerol on Pt electrodes

This research explores the glycerol electrooxidation reaction (GEOR) on a platinum electrode, with a special emphasis on the role of the chemical properties of the anion present in the electrolyte composition. Essential knowledge of the mechanism and dynamics of glycerol electrooxidation is obtained through comprehensive studies that involve in situ FTIR measurements and the analysis of electrochemically oscillatory responses. This study addresses on the complex interplay between anion adsorption strength and the GEOR, focusing on the differences in CO adsorption coverage, which is the main strongly adsorbed intermediate. The anion adsorption strength, with the order HClO4 < H2SO4 < H3PO4, affects significantly not only the CO coverage on the platinum surface but also the overall glycerol electrooxidation rate. The observed differences in the electroactivity are attributed to competitive adsorption phenomena, in which specific coordinated ions have greater adsorption capabilities than perchlorate ions. These findings highlight the critical relevance of designing and optimizing electrocatalysts for glycerol electrooxidation and related processes with careful consideration of the electrolyte composition, notably the anion.

A novel ion-responsive hydrogel based on quaternized chitosan and hydroxyethyl cellulose for high efficient chloride ion adsorption

Chloride removal is crucial for industrial wastewater discharge, seawater purification and concrete structure durability. In this study, a novel hydrogel with excellent chloride adsorption property was prepared and the adsorption capacity in relation to external pH and other ions was evaluated. The hydrogel was synthesized using a one-pot method with quaternized chitosan (HACC), hydroxyethyl cellulose (HEC), and carboxymethyl chitosan (CMC) as monomers. By adjusting the material compositions, we effectively modulated the microstructure and charge characteristics of hydrogel, achieving a balanced swelling ratio and optimal adsorption performance. The optimal process conditions were identified as 25 °C and a chloride ion concentration of 40 mmol L−1, achieving a maximum adsorption capacity of 1080 mg g−1. Isotherm modeling showed that the adsorption fits well with the Freundlich isotherm, suggesting multilayer adsorption. The quaternary ammonium groups serve as fixed positive charge sites or active adsorption sites, enabling the hydrogel to efficiently adsorb anions through the synergistic effects of electrostatic interactions, physical adsorption, and amino protonation. The varied adsorption capacities of quaternary ammonium groups for different anions give rise to competitive adsorption phenomena among them. The incorporation of silver ions into the hydrogel greatly enhances its selective adsorption of chloride ions through chemical combination. This work presents a comprehensive strategy for designing a novel hydrogel with exceptional adsorption properties specifically tailored for chloride ions.

An adsorption micro mechanism theoretical study of CO2-rich industrial waste gas for enhanced unconventional natural gas recovery: Comparison of coalbed methane, shale gas, and tight gas

Direct injection of CO2-rich industrial waste gas to displace unconventional natural gas is proposed as an energy-saving and green development method. In this work, the Giant canonical Monte Carlo and molecular dynamics methods were employed to compare the adsorption mechanisms of this method in three typical unconventional gas reservoirs, which are coal seam, shale and tight sandstone. It is found in the adsorption configurations that the proportion of gas molecules in the free state is higher in tight sandstone than in shale and coal seam. The adsorption energy of CH4/waste gas components on all reservoirs is in the order of CH4/SO2 > CH4/CO2 > CH4/NO > CH4/N2, among which the absolute value of the CH4/SO2 adsorption energy on the coal seam reaches the highest 64.220 kJ/mol. The adsorption selectivity of SO2, CO2 and NO over CH4 is greater than 1.0 in all reservoirs at depths of 0.5–4.0 km, and the competitive adsorption phenomenon in the deep reservoirs has a severe negative effect on it. Gas adsorption mode in the tight sandstone is dominated by filling pore structures, while gas adsorption in the coal seam is highly correlated with adsorption sites. This study is instructive for enhanced unconventional natural gas recovery by CO2-rich industrial waste gas injection from the perspective of gas adsorption.

Promote the efficient co-combustion of toluene & CO in Pt/CeO2 catalyst: Orientally adjusting the oxidized SMSI to optimize acid site and oxygen vacancy

By effectively controlling the strong metal-support interaction (SMSI), the formation of acid sites and oxygen vacancies (Ov) on the Pt/CeO2 catalyst was optimized. The efficient co-combustion of toluene and CO on Pt/CeO2-450 was achieved. In the dual-pollutant system, when the conversion rate was 90 %, the corresponding conversion temperatures of toluene and CO were 165 °C and 173 °C, respectively. With the increase of SMSI, the catalytic activity of Pt/CeO2 showed a trend of first increase and then decrease. This was proportional to the content of weak acid sites, medium acid sites, and Ov generated on their surfaces. Compared with the combustion of a single pollutant, the result displays that toluene and CO had significant competitive adsorption on Pt/CeO2. The inhibition of toluene on CO also showed the same trend as the catalytic activity with the increase of SMSI. Under the double inhibition, Pt/CeO2 exhibited preferential selectivity for toluene combustion. However, the in situ DRIFTS results showed that this competitive adsorption phenomenon did not interfere with the combustion reaction path. The co-combustion of toluene and CO follows independent reaction paths. This work provides valuable insights and ideas for realizing the development of efficient and environmentally friendly catalysts through SMSI regulation.

Unravelling competitive adsorption phenomena in the aqueous phase reforming of carboxylic acids on Pt catalysts: An experimental and theoretical study

Biorefinery-derived wastewater is considered a valuable source of energy and chemicals thanks to its organic loading. However, it is constituted by different compounds which influence the performance of a catalytic valorization process. In this work, we investigated the treatment of a synthetic hydrothermal liquefaction-derived wastewater (HTL-WW) via aqueous phase reforming (APR) to obtain hydrogen. As a case study, we examined the underlying driving forces for performance differences in the APR of mono- and bi-component solutions of carboxylic acids as a model corn stover HTL-WW over Pt catalysts via a combined experimental and theoretical approach. In mono-component solutions, the conversion ranked as glycolic acid > propionic acid ≈ acetic acid, and the same was found for the hydrogen production tendency. Binary solutions of glycolic and acetic acid, with different concentration among the constituents, showed a strong inhibition of the acetic acid reactivity due to the prevalent adsorption of glycolic acid on Pt surface. The results from the APR of acetic and propionic acid solutions were less affected by such phenomena. DFT results showed that there are strong, attractive lateral interactions between carboxylic acids due to intermolecular hydrogen bonding that cause all carboxylic acids to preferentially adsorb in dimer structures. The lateral interaction strength was determined for both pure and binary mixtures of carboxylic acid dimers, with results showing that pure mixtures of carboxylic acids have stronger attractions and that glycolic acid dimers see the strongest attractions due to the added terminal hydroxyl functional group. The findings presented herein offer significant insights into the utilization of APR for industrial-like multi-component solutions, as well as for any catalytic process involving small organic compounds in an aqueous phase.

Addressing the issue of surface mechanisms and competitive effects in Cr(VI) reductive-adsorption on tin-hydroxyapatite in the presence of co-ions

Our group recently proposed an innovative sustainable reductant-adsorbent material, tin(II)-hydroxyapatite (Sn/HAP, ca. 10 wt% Sn) for the interfacial Cr(VI) reductive adsorption process. In this study, Cr(VI) removal capacity was evaluated in multi-component solutions containing representative background ions (i.e., CaCl2, Ca(NO3)2, MgSO4, Na2SO4, Fe(NO3)3, AlCl3, Zn(NO3)2, or Mn(NO3)2). Sn/HAP was able to reduce Cr(VI) with complete Cr3+ adsorption on HAP surface, except in the presence of Fe3+ and Al3+ ions. Some metal ions co-existing in solution, such as Fe3+, Al3+, Zn2+, and Mn2+, were also adsorbed on HAP surface. Reuse experiments of the Sn/HAP sample, up to 7 runs, resulted in a total amount of reduced Cr(VI) of ca. 15–18 mg g−1. Fast kinetics of Cr(VI) reductive adsorption at 25 °C in a multi-metal component solution was observed. The pseudo-second order model was in excellent agreement with the experimental kinetic data, leading to a rate constant (k25°C) value of ca. 30 M−1 s−1. The collection of adsorption isotherms of Cr3+ and Fe3+, together with TEM–EDX analysis permitted the unveiling of competitive adsorption phenomena between metal ions. The obtained results demonstrate that Sn/HAP could be an efficient material for the removal of hexavalent chromium in aqueous solutions containing high concentrations of inorganic impurities.

Phosphorus can effectively reduce selenium adsorption in selenium-rich lateritic red soil

Phosphorus (P) application can improve the availability of selenium (Se) in soil, which benefits the output of Se-rich agricultural products. However, the mechanism by which P affects the adsorption of Se in Se-rich soil is still unclear. Therefore, this study took Se-rich lateritic red soil as the research object and studied the adsorption behavior of P and Se in the soil through batch adsorption tests and soil characterization technology. The results showed that the adsorption of P or Se in lateritic red soil increased with an increase in equilibrium concentration. The P or Se adsorption process was explained using the Langmuir and Freundlich isotherm models. After adding P, the adsorption of Se decreased from 276–423 mg/kg to 52–201 mg/kg at different initial Se concentrations. The scanning electron microscope and energy dispersive spectrometry (SEM-EDS) results showed that the lateritic red soil was rich in C, O, Fe, Al, and other elements, and the free oxidation states of these elements could efficiently facilitate the adsorption of P and Se. Fourier infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses indicated that both Se and P could react with ferrite groups in the soil to form iron-containing complexes, and there was a competitive adsorption phenomenon, which was the main reason for the decrease in Se adsorption. This study provides theoretical support for further exploring the effect of P on Se behavior in the geochemical cycle. Furthermore, it promotes the efficient use of Se-rich soil resources.

Exploring the simultaneous mass transport of nimesulide and paracetamol adsorption on activated carbon: A PVSDM approach

Pore Volume and Surface Diffusion Model (PVSDM) was advanced to Extended PVSDM for modeling multicomponent adsorption systems. The dynamic adsorption of nimesulide and paracetamol on activated carbon was investigated through single and binary adsorption experiments. Langmuir and Extended Langmuir isotherms were used as local equilibrium functions, respectively. The results reveal that single and binary adsorption were affected by both external mass transport and intraparticle diffusion. The coexistence of nimesulide and paracetamol led to a competitive adsorption phenomenon, wherein nimesulide exhibited a higher affinity for the activated carbon surface, primarily occupying its surface active sites, while paracetamol diffuse into the pore volume to be adsorbed, especially at higher initial pharmaceutical concentrations. These findings emphasize the necessity of employing the robust Extended PVSDM for predicting the complex dynamics of binary adsorption. The findings also provide valuable insights that can significantly contribute to the development of efficient adsorption processes, addressing urgent environmental challenges.

Experimental investigation on the effect of interfacial properties of chemical flooding for enhanced heavy oil recovery

Chemical compound flooding has demonstrated its efficacy in enhancing light oil recovery through ultra-low interfacial tension (IFT). However, the optimization of chemical systems properties for displacing heavy oil has not been clarified. This research aims to address this problem by designing common polymer and three surfactant-polymer (SP) systems with varying IFT and interfacial viscoelasticity behaviors, and comparing their ability to recover heavy oil. The findings of core flooding tests indicate that the system with low IFT and high interfacial viscoelasticity simultaneously has a better displacement efficiency for heavy oil than other flood systems, which could enhance heavy oil recovery by 21.94%. Micro-model tests reveal the underlying mechanisms driving the enhanced macro-scale oil recovery. The emulsion formation and interface expansion facilitated by low IFT, as well as increased emulsion stability and reduced snap-off of oil droplets due to the presence of an elastic oil-water interfacial film. These phenomena is more capable of driving microscopic heterogeneous remaining oil and film remaining oil than other solution. The comparative experiment analysis shows that the difference in chemical flooding between heavy oil and light oil is caused by the discrepant distributions of surfactants at the oil-water interface. The light oil interface is a monolayer surfactant molecular film, the heavy components and surfactant moleculars exhibit both competitive and cooperative adsorption phenomena at the oil-water interface. The occurrence of viscosity reduction and increased emulsion stability are more influential factors in the process of heavy oil displacement than those of conventional ultra-low IFT systems used for light oil recovery.

Removal performance and inhibitory effects of combined tetracycline, oxytetracycline, sulfadiazine, and norfloxacin on anaerobic digestion process treating swine manure

Combined veterinary antibiotics (CVAs) belonging to different antibiotics classes could cause exacerbated impacts on the anaerobic digestion (AD) process of swine manure. Four different antibiotics “two tetracyclines: tetracycline (TC) and oxytetracycline (OTC), one fluoroquinolones: norfloxacin (Norf), and one sulfonamides: sulfadiazine (SDZ)” were combined to evaluate their removal performances and its inhibition effects on AD. Results indicated that CVAs removal decreased from 84.3 to 63.7 %, with an increase in the initial concentration from 12.5 to 50 mg L−1, where the removal of CVAs occurring in the order OTC > TC > Norf > SDZ. An average of 9.5, 7.5, 9.5, and 32.1 % of the spiked TC, OTC, SDZ, and Norf were remained in the sludge, respectively. With 50 mg L−1 of CVAs, a competitive adsorption phenomenon was found to have a notable impact on biodegradation microorganisms' activity leading a 73.1 % decrease in CH4 production. CVAs caused a temporal inhibition to the acidogenic activity followed by partial inhibition to methanogenic by 66.8 %, and IC50 was 38.5 mg L−1. Moreover, CVAs resulted in acetate accumulation, while 26 % and 48 % lower in TS and COD removal, respectively, were observed. A significant reduction in the relative abundance of bacteria and archaeal genera was also mentioned. The findings of this research would provide a more in-depth understanding of AD's performance in treating swine manure contaminated with combined antibiotics.

Effects of delayed addition of polycarboxylate ether on one-part alkali-activated fly ash/slag pastes: Adsorption, reaction kinetics, and rheology

The admixture addition method is one of the vital factors influencing the fresh performance of ordinary Portland cement (OPC) through directly affecting the adsorption, hydration, and rheology. However, such an issue is less researched in the one-part alkali-activated materials (AAMs), which have great potentials in the industry due to their simple operation, similar to OPC. This study reports and discusses the effects of delayed polycarboxylate ether (PCE) addition at different contents on adsorption, reaction kinetics, and rheology of one-part AAMs. It is found that the delayed PCE addition had minimized the competitive adsorption phenomenon and reduced the consumption rate of PCE surfactants, which in turn facilitates easier adsorption of silicate species onto the GGBS grains. This had decreased the retardation effect of PCE, slightly improved the compressive strength, and lowered the viscosity and yield stress of the one-part AAMs. The mechanisms that govern such observations are further discussed.

Cationic surfactant-directed structural control of NaCl crystals from evaporating sessile droplets.

We report morphological regulation of NaCl (sodium chloride) crystals through the evaporative crystallisation process of microdroplets containing a cationic surfactant CTAB (cetyltrimethylammonium bromide). Various fascinating evaporative salt morphologies are observed using different combinations of salt (CNaCl) and surfactant (CCTAB) concentrations. Each observed morphology is carefully explained by the interplaying physical phenomena, such as crystallisation, micellisation, evaporative dewetting, and surface adsorption of anionic couneterions. Salt morphologies are investigated for low (CNaCl = 0.1 (M)), intermediate (CNaCl = 0.5 (M)) and high (CNaCl = 2 (M)) concentrations, whereas surfactant concentrations are varied four orders of magnitudes (from 0.0001 (M) to 0.1 (M)). Interestingly, we observe a threshold in CCTAB at 0.001 (M), beyond which the peripheral rings of dried deposits are found to be composed of CTAB for CNaCl = 0.1 (M), while the same is seen to be made up of NaCl for CNaCl = 2 (M). We have explained the morphological evolution by the process of competitive surface adsorption phenomenon between Cl- and Br- counter ions. Such a detailed study of saline droplet crystallisation in the presence of a cationic surfactant underpins the fundamental understanding of the crystallisation process. In addition, it may further impact application sectors where crystallisation of saline solution plays an important role, especially in the presence of additives.

Understanding the interaction mechanism of algal cells and soluble algal products foulants in forward osmosis dewatering

Forward osmosis (FO) has increasingly been an energy saving technology in microalgae dewatering, whereas membrane fouling is still a major obstacle for FO application. To explore the fouling mechanism of algal cells and their organic matters during microalgal FO dewatering process, Chlorella vulgaris and Scenedesmus obliquus were adopted as algae species, and the algae-derived foulants including algae cells, soluble algal products (SAP) and algal broth were used as feed solutions. The water fluxes behaviors of algal foulants had been investigated, and the dissolved organic carbon (DOC), protein and carbohydrates proportions of the feed solutions were then characterized, followed by the scanning electronic microscopy (SEM) and the analysis of extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory for the FO membrane foulants. The results indicated that algal broth resulted in the fastest flux decline due to the combined fouling between SAP and algae cells. The competitive adsorption phenomenon between cells and SAP was found in C. vulgaris broth but not in S. obliquus, resulting in a high protein content loss in the feed solution of C. vulgaris. The fouling potential of those individual and combined feed solutions could be well predicated using the XDLVO theory, and the higher the interfacial energy, the faster the flux decline was found for both adhesion and cohesion stages. The findings improve the understanding of FO membrane fouling mechanism by microalgae, indicating the selection of algae species for FO processes.

Surfactant changes lead adsorption behaviors and mechanisms on microplastics

The impact of surfactant addition on the adsorption performance of lead ion (Pb2+) as a typical heavy metal ion on three microplastics was investigated. The types of microplastics (polyethylene (PE), polypropylene (PP) and polymethylmethacrylate (PMMA)) and surfactants (triton X-100 (TX-100), 1-hexadecylpyridinium bromide (HDPB), and sodium dodecyl benzenesulfonate (SDBS)), adsorption time, concentration of Pb2+, and coexisting ions was systematically investigated, and the characteristics of adsorption of Pb2+ by microplastics were analyzed. The experimental results showed that the adsorption capacity of Pb2+ on three micropalstics was different. The adsorption capacity of Pb2+ on the three microplastics without surfactants was: 4.21 (PMMA) > 2.01 (PE) > 1.57 mg g−1 (PP). The addition of surfactants resulted in a higher hydrophilicity of microplastics, and obviously improved the adsorption ability of microplastics for lead ions. SDBS can significantly enhance the adsorption of Pb2+ on three microplastics compared with other two surfactants (TX100 and HDPB). The highest adsorption capacity of Pb2+ on the three microplastics with addition of SDBS solution was: 7.87 (PMMA) > 7.20 (PE) > 7.02 mg g−1 (PP). With the increase of adsorption time and Pb2+ concentration, the adsorption efficiency of microplastics for Pb2+ first increased and then decreased. The pH of solution had a great influence on the adsorption of Pb2+ by microplastics. The results of coexisting ion experiments demonstrated that when lead ion and copper ion coexist, the two ions have competitive adsorption phenomenon on PP. This research explored the adsorption characteristics of lead ions by microplastics with addition of surfactants, which can provide theoretical basis for further study of heavy metal enrichment and environmental behavior of microplastics in the environment.

Synergic and competitive adsorption of Li–Na–MgCl2 onto lithium–aluminum hydroxides

Layered lithium–aluminum hydroxides have been used for the lithium adsorption for its high selectivity and cyclic stability. The adsorption performances of lithium and sodium in the mixing solution with abundant magnesium chloride were investigated using batch system at 303 K. The lithium adsorption capacity was increased from 5.02 to 5.69 mg/g (initial lithium concentration is 350 mg/L) with the increasing of initial chloride ions concentration from 200 to 350 mg/L, while the sodium decreased. Both the adsorption capacities of lithium and sodium were lower in Li–Na–MgCl2 system than that’s in Li–MgCl2 and Na–MgCl2 system, which indicated the competitive effects between lithium and sodium ions. In addition, the Langmuir model could describe the isotherms of lithium and sodium well. Then, the homogeneous surface diffusion model (HSDM) was applied to represent the lithium adsorption kinetics. The surface diffusion coefficients of lithium were dependent on the initial concentration and affected by sodium ions. The Biot numbers were ranged from 25 to 40 confirming that the intraparticle diffusion is the limiting step. Breakthrough curves of lithium and sodium demonstrated the lithium could be enriched and obtained with fixed bed adsorption process, and verified the competitive adsorption phenomenon.

On competitive gas adsorption and absorption phenomena in thin films of ionic liquids

The equipartition thickness provides a way to design advanced materials with task-specific surface properties and to predict their adsorption performance.

The contribution of oxygen-containing functional groups to the gas-phase adsorption of volatile organic compounds with different polarities onto lignin-derived activated carbon fibers.

Lignin-based activated carbon fibers (LCFK) were prepared by electrospinning method and evaluated in adsorption of volatile organic compounds (VOCs). Batch adsorption experiments for various component were carried out in a fixed-bed reactor. The molecular polarity of VOCs plays a pivotal role in the monocomponent dynamic adsorption. As a result, the adsorption capacity of toluene was larger than that of methanol or acetone. In the various multicomponent atmospheres (without water), the components interact with each other and competitive adsorption phenomenon occurs, resulting in the adsorption capacity of each component decreased significantly. Also, the samples before and after adsorption were characterized via Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and Boehm titration. The results reveal that methanol and acetone, controlled by physical adsorption, prefer to be adsorbed on polar groups on the surface of LCFK through the dipole-dipole interactions (i.e., van der Waals' forces). Differently, the adsorption of toluene onto LCFK was controlled by physical and chemical processes, and the lactone groups have a positive contribution to the adsorption of toluene. It was also observed that water vapor can enhance the negative effect on the adsorption of VOCs, especially for toluene. The results from this study will be valuable for explaining the mechanisms of competitive adsorption among each component in the various multicomponent atmospheres and understanding the contribution of chemical functional groups on the surface of LCFK in the adsorption process.

Competitive adsorption phenomenon in shale gas displacement processes.

Displacement of methane (CH4) by injection gas is regarded as an effective way to exploit shale gas and sequestrate carbon dioxide (CO2) simultaneously. To remarkably enhance the rupture and extension of fractures, an original and comprehensive simplification for the real shale composition model is established to study the shale gas displacement by gas injection. In the present model, besides the consideration in the existence of organic matter in shale, the choice of silica as inorganic minerals is firstly taken into account considering its brittleness characteristic to meet the demand of fracture stretch. Based on the model, the displacement methane process and competitive adsorption behaviors were studied by using the grand canonical Monte Carlo (GCMC) and molecular dynamics (MD) respectively. As the results, the strong interaction between carbon dioxide and shale results in the higher efficiency of displacing methane. We also find that the optimum operating conditions for CO2 and N2 displacing methane are at the pore width of 30 Å, the result being slightly different from the previous studies indicating that the displacement efficiency of small pores is higher. Moreover, the displacement efficiency by using different gases can all reach higher than 50% when the injection pressure is greater than 30 MPa. It is expected that this work can reveal the mechanisms of competitive adsorption between shale gas and gases, and provide a guidance for displacement exploitation of shale gas by gas injection and sequestration of carbon dioxide.

In-depth study of the mechanism of heavy metal trapping on the surface of hydroxyapatite

In the present study, the efficiency and selectivity and the role of surface groups of hydroxyapatite in the Cr(III) trapping, present in solution as single species or in co-presence of Ni(II) and Pb(II), have been investigated. Transmission electron microscopy (TEM) analysis and synchrotron radiation X-ray powder diffraction (XRPD) measurements provided comprehensive descriptions of the HAP surface and structure. The surface chemical properties, density and strength of the acid and base sites of HAP, have been determined by 2-phenylethylamine and benzoic acid probe adsorption, respectively. The amphoteric properties of HAP turned over to only acid property in water solution. The sorption capacity of HAP has been batch-tested in simulated polluted waters containing Cr(III) at different initial concentrations (from ca. 0.3 to ca.6 mM) and pH values (from 4 to 9). Competitive adsorption phenomena in multi-metal systems (Cr(III) with Ni(II) and Pb(II)) have also been studied. An appropriate set of analytical techniques, XRPD, TEM, STEM-EDX, N2 adsorption-desorption analyses, FT-IR spectroscopy, have been used to characterize the metal loaded hydroxyapatite samples. Different mechanisms of metal uptake were active depending on the nature of the metal species and pH value of solutions: surface complexation, precipitation, ion-exchange, or dissolution-precipitation.

Use of cell wall degrading enzymes to improve the recovery of lipids from Chlorella sorokiniana

An enzymatic treatment with cell wall degrading enzymes aimed at improving the recovery of lipids from Chlorella sorokiniana was investigated. Six commercial enzyme preparations containing cellulase, pectinase, lysozyme and three different hemicellulases were preliminary tested. The most effective preparations were then used as basic components for the formulation of enzyme cocktails with high cell wall degrading activity. Experiments were carried out according to the mixture design methodology. Analysis of the results revealed the occurrence of both synergistic and antagonistic effects which were, respectively, attributed to the cooperative destructuring of the cell wall and to non-productive competitive adsorption phenomena. A numerical optimization procedure was used to design an optimal enzyme mixture containing β-1,4-xylanase and β-1,4-mannanase in the ratio of 61:39 (% w/w). Pretreatment of C. sorokiniana by this mixture provided a lipid extraction yield of (74.74 ± 1.02)%. For comparison, the extraction yields from the untreated and water-pretreated biomass were, respectively, equal to (36.19 ± 2.33)% and (58.36 ± 1.22)%.