Charged Sites Research Articles

An ultraprocessive, accurate reverse transcriptase encoded by a metazoan group II intron.

Group II introns and non-LTR retrotransposons encode a phylogenetically related family of highly processive reverse transcriptases (RTs) that are essential for mobility and persistence of these retroelements. Recent crystallographic studies on members of this RT family have revealed that they are structurally distinct from the retroviral RTs that are typically used in biotechnology. However, quantitative, structure-guided analysis of processivity, efficiency, and accuracy of this alternate RT family has been lacking. Here, we characterize the processivity of a group II intron maturase RT from Eubacterium rectale (E.r.), for which high-resolution structural information is available. We find that the E.r. maturase RT (MarathonRT) efficiently copies transcripts at least 10 kb in length and displays superior intrinsic RT processivity compared to commercial enzymes such as Superscript IV (SSIV). The elevated processivity of MarathonRT is at least partly mediated by a loop structure in the finger subdomain that acts as a steric guard (the α-loop). Additionally, we find that a positively charged secondary RNA binding site on the surface of the RT diminishes the primer utilization efficiency of the enzyme, and that reengineering of this surface enhances capabilities of the MarathonRT. Finally, using single-molecule sequencing, we show that the error frequency of MarathonRT is comparable to that of other high-performance RTs, such as SSIV, which were tested in parallel. Our results provide a structural framework for understanding the enhanced processivity of retroelement RTs, and they demonstrate the potential for engineering a powerful new generation of RT tools for application in biotechnology and research.

Versatile Tool for the Analysis of Metal-Protein Interactions Reveals the Promiscuity of Metallodrug-Protein Interactions.

Metallodrug-protein interactions contribute to their therapeutic effect (even when DNA is the dominant target), side-effects and are implicit in drug resistance. Here, we provide mass spectrometric-based evidence to show that metallodrug interactions with proteins are considerably more complex than current literature would suggest. Using native-like incubation and electrospray conditions together with an automated tool we designed for exhaustive mass spectra matching, the promiscuity of binding of cisplatin to ubiquitin is revealed, with 14 different binding sites observed. There is a binding preference to negatively charged sites on the protein, consistent with the cationic nature of the cisplatin adduct following aquation. These results have implications in metallodrug development and beyond to the toxicological effects of metal ions more generally.

Selective Hydrogenation of Acetylene over Pd-In/Al2O3 Catalyst: Promotional Effect of Indium and Composition-Dependent Performance

Highly dispersed bimetallic Pd-In catalysts on Al2O3 were prepared by a simple impregnation method. In comparison with the unsupported intermetallic catalyst, the supported Pd-In catalyst exhibited several magnitudes higher activity and similar selectivity for selective acetylene hydrogenation. Moreover, the activity, selectivity, and anticoking performance of the Pd-In catalyst were superior to those of the monometallic Pd catalyst. The electron transferred from indium weakened the adsorption of ethylene on the negatively charged Pd sites and hence improved the selectivity of Pd-In/Al2O3. The inhibited formation of hydride due to the presence of indium also contributed to the higher selectivity. The promoted activation of hydrogen, owing to the weak adsorption of acetylene on Pd-In/Al2O3, and decreased particle size jointly contributed to the enhanced activity of Pd-In/Al2O3. In addition, green oil formation on Pd-In/Al2O3 was retarded by the presence of indium, contributing to the enhanced stability of ...

Surface Charge Density Determination in Water Based Magnetic Colloids: a Comparative Study

This work focuses on the systematic investigation of the two well-established methods of structural surface charge density determination on magnetic colloids, labeled as Single Potentiometric Method (SPM) and Potentiometric-Conductometric Method (PCM). To compare some important features of the methods we determined the structural surface charge density of magnetic colloids samples based on CoFe2O4@ɣ-Fe2O3 core-shell nanoparticles with three different mean sizes using both strategies. Concerning quickness, easiness and cost, the PCM has proved to be more advantageous than the SPM. Regarding the effectiveness, both methods were consistent in determining the saturation value of the structural charge, but the SPM was more accurate to describe the pH-dependence of the concentration of the charged surface sites. Considering the chemical safety, the methods are equivalent. Finally, both the SPM and PCM are reproducible and can be effectively applied to determine the saturation value of the surface charge density on magnetic colloids.

Ion-induced alterations of the local hydration environment elucidate Hofmeister effect in a simple classical model of Trp-cage miniprotein.

Protein stability is known to be influenced by the presence of Hofmeister active ions in the solution. In addition to direct ion-protein interactions, this influence manifests through the local alterations of the interfacial water structure induced by the anions and cations present in this region. In our earlier works it was pointed out that the effects of Hofmeister active salts on the stability of Trp-cage miniprotein can be modeled qualitatively using non-polarizable force fields. These simulations reproduced the structure-stabilization and structure-destabilization effects of selected kosmotropic and chaotropic salts, respectively. In the present study we use the same model system to elucidate atomic processes behind the chaotropic destabilization and kosmotropic stabilization of the miniprotein. We focus on changes of the local hydration environment of the miniprotein upon addition of NaClO4 and NaF salts to the solution. The process is separated into two parts. In the first, 'promotion' phase, the protein structure is fixed, and the local hydration properties induced by the simultaneous presence of protein and ions are investigated, with a special focus on the interaction of Hofmeister active anions with the charged and polar sites. In the second, 'rearrangement' phase we follow changes of the hydration of ions and the protein, accompanying the conformational relaxation of the protein. We identify significant factors of an enthalpic and entropic nature behind the ion-induced free energy changes of the protein-water system, and also propose a possible atomic mechanism consistent with the Collins's rule, for the chaotropic destabilization and kosmotropic stabilization of protein conformation.

Molecular modeling, pK a and thermodynamic values of asthma drugs

This study investigates on optimized structure, pK a values and thermodynamic properties of four asthma drugs, e.g., salbutamol, terbutaline, salmeterol, and formoterol, in aqueous solution using ab initio and DFT methods at different temperatures. The molecular conformations and solute–solvent interactions of the cations, neutrals, and anions molecules of the drugs were investigated. Further, the best ionization reaction and Tomasi’s method at the B3LYP/6-31 + G(d) level of theory were used to calculate ∆G and pK a values. For the validation, the pK a values and ionization mechanisms of salbutamol and terbutaline are calculated. Furthermore, ionization schemes are proposed for formoterol and salmeterol drugs, and their pK a values at different temperature are calculated. Moreover, the chemical reactions tendency calculation showed that net electrophilicity of terbutaline, the chemical potential of salbutamol, and electronegativity of formoterol were more than the other four asthma drugs in this work. Theoretical calculation of HOMO–LUMO gap shows that the maximum and minimum gaps were for salbutamol and terbutaline, respectively. Besides, charge density distribution and site of chemical reactivity of the asthma drugs are studied by mapping electron density isosurface with molecular electrostatic potential (MEP). Also, thermodynamic properties of the drugs in aqueous solution show negative values for ∆S and positive values for ∆G.

Mixed-matrix membranes with enhanced antifouling activity: probing the surface-tailoring potential of Tiron and chromotropic acid for nano-TiO2.

Mixed-matrix membranes (MMMs) were developed by impregnating organofunctionalized nanoadditives within fouling-susceptible polysulfone matrix following the non-solvent induced phase separation (NIPS) method. The facile functionalization of nanoparticles of anatase TiO2 (nano-TiO2) by using two different organoligands, viz. Tiron and chromotropic acid, was carried out to obtain organofunctionalized nanoadditives, FT-nano-TiO2 and FC-nano-TiO2, respectively. The structural features of nanoadditives were evaluated by X-ray diffraction, X-ray photoelectron spectroscopy, Raman and Fourier transform infrared spectroscopy, which established that Tiron leads to the blending of chelating and bridging bidentate geometries for FT-nano-TiO2, whereas chromotropic acid produces bridging bidentate as well as monodentate geometries for FC-nano-TiO2. The surface chemistry of the studied membranes, polysulfone (Psf): FT-nano-TiO2 UF and Psf: FC-nano-TiO2 UF, was profoundly influenced by the benign distributions of the nanoadditives enriched with distinctly charged sites (), as evidenced by superior morphology, improved topography, enhanced surface hydrophilicity and altered electrokinetic features. The membranes exhibited enhanced solvent throughputs, viz. 3500–4000 and 3400–4300 LMD at 1 bar of transmembrane pressure, without significant compromise in their rejection attributes. The flux recovery ratios and fouling resistive behaviours of MMMs towards bovine serum albumin indicated that the nanoadditives could impart stable and appreciable antifouling activity, potentially aiding in a sustainable ultrafiltration performance.

Boron Removal by Adsorption on Cobalt(II) Doped Chitosan Bio-composite

Cobalt(II) doped chitosan bio-composite was prepared, characterized and used to oxoborate separation from aqueous solutions. The adsorption process was carried out in a batch system. The effect of pH, temperature, time and initial boron concentration on the boron adsorption were tested. The maximum boron adsorption was reached at pH range 8.0–8.5 at room temperature and within 60 min. Calculations based on Langmuir and Freundlich models showed the heterogeneous nature of boron adsorption on Co-CTS bio-composite. On the base of research on optimization of pH and results from XRD and FTIR analysis it was found that boron adsorption by Co-CTS occurred through the co-precipitation and adsorption of B on cobalt hydroxide following the Coulomb attraction of B(OH)4− species on positively charged sites and molecular attraction of H3BO3 through hydrogen bond with amine or hydroxyl groups of chitosan. The modelling of the thermodynamic data indicated the nonspontaneous and exothermic nature of the adsorption process. The pseudo-second-order model adequately described the boron adsorption on Co-CTS hydrogel. Desorption by means of alkaline solution at pH 12 was carried out successfully. Adsorption–desorption efficiencies in 3 cycles were almost 100%.

Removal of Pb2 + ions from aqueous solutions by fixed-BED column using a modified brick: (Micro)structural, electrokinetic and mechanistic aspects

Brick was pre-activated with HCl and subsequently coated with ferrihydrite. To assess the potential of this modified brick for Pb2+ removal, adsorption experiments were conducted in a fixed-bed continuous-flow column system. The prediction of breakthrough curves was obtained by using the Thomas model. MINTEQ computations revealed that Pb2+ and Pb(OH)+ are the major species present in the column solution. Potentiometric analysis and electrophoretic mobility measurements provided strong evidence of the surface basicity of coated brick due to the existence of sodic negatively charged sites: >SO−Na+ with SFe; Si; or Al. Using Environmental Scanning Electron Microscopy (ESEM) equipped with an Energy Dispersive X-Ray Spectroscopy (EDS), micro-analyses showed clearly that Na atoms present in coated brick are preferentially bound to ferrihydrite specimens. The ESEM/EDS technique allowed to further highlight discrete PbFe combinations and to contend that Pb2+ ions are better adsorbed onto Fe-rich aggregates than onto SiO2 and alumino-silicates (clays). Before the breakthrough time, the pH in the effluent solution was found to be dependent upon the electrokinetic characteristics of coated brick. After this time, the pH was instead governed by the acidity of not adsorbed lead(II). To support this, simulation calculations relative to the pH evolution in the column medium were made. The addition of a background electrolyte (Na+NO3−) led nevertheless to a weaker adsorption capacity of Pb2+ on coated brick, because positively charged Na ion competed favorably at the expense of lead(II) via electrostatic attraction forces.

Characterization of Intramolecular Interactions of Cytochrome c Using Hydrogen-Deuterium Exchange-Trapped Ion Mobility Spectrometry-Mass Spectrometry and Molecular Dynamics.

Globular proteins, such as cytochrome c (cyt c), display an organized native conformation, maintained by a hydrogen bond interaction network. In the present work, the structural interrogation of kinetically trapped intermediates of cyt c was performed by correlating the ion-neutral collision cross section (CCS) and charge state with the starting solution conditions and time after desolvation using collision induced activation (CIA), time-resolved hydrogen/deuterium back exchange (HDX) and trapped ion mobility spectrometry-mass spectrometry (TIMS-MS). The high ion mobility resolving power of the TIMS analyzer allowed the identification of new ion mobility bands, yielding a total of 63 mobility bands over the +6 to +21 charge states and 20 mobility bands over the -5 to -10 charge states. Mobility selected HDX rates showed that for the same charge state, conformers with larger CCS present faster HDX rates in both positive and negative ion mode, suggesting that the charge sites and neighboring exchange sites on the accessible surface area define the exchange rate regardless of the charge state. Complementary molecular dynamic simulations permitted the generation of candidate structures and a mechanistic model of the folding transitions from native (N) to molten globule (MG) to kinetic intermediates (U) pathways. Our results suggest that cyt c major structural unfolding is associated with the distancing of the N- and C-terminal helices and subsequent solvent exposure of the hydrophobic, heme-containing cavity.

Wiring of heme enzymes by methylene-blue labeled dendrimers

Redox-modified branched 3D dendrimeric nanostructures may be considered as perspective wires for electrical connection between redox enzymes and electrodes. Here, we studied electron transfer (ET) reactions and bioelectrocatalysis of heme-containing horseradish peroxidase (HRP) and heme- and molibdopterin-containing sulfite oxidase (SOx), wired to gold by the methylene blue (MB)-labeled polyamidoamine (PAMAM) dendrimers. The enzymes’ electrochemical transformation and bioelectrocatalytic function could be followed at both unlabeled and MB-labeled dendrimer-modified electrodes with the formal redox potentials of the heme centers being at −341mV for HRP and −185mV for SOx. In contrast to the HRP-dendrimer and HRP-MB-dendrimer systems, which demonstrated very close bioelectrocatalytic patterns, multicofactor SOx wired to MB-dendrimer showed a bioelectrocatalysis superior to that based on direct ET reaction. This can be correlated with a statistically larger number of positively charged MB sites on the dendrimer surface able to electrically connect the negatively charged heme domain of SOx and the electrode. In this perspective, redox-labeled dendrimers appear to be useful tools for wiring, optimization of bioelectrocatalysis of complex intermembrane and, possibly, membrane enzymes.

Adsorption behavior of methylene blue by bone char

This work studies the adsorption behavior of methylene blue (MB) from water by bone char (BC). The effects of pH, initial dye concentration and dosage of adsorbent on the adsorption were investigated. It was found that the adsorption capacity of MB was affected by the mount of OH[Formula: see text], initial concentration gradient driving force of MB, the surface charge and adsorption site of BC.

R1ρ dispersion and sodium imaging in human calf muscle

PurposeTo evaluate the magnitude of chemical exchange effects and R1ρ dispersion in muscle and their relationship to tissue sodium levels with aging. MethodsSeven healthy volunteers (aged 24 to 87years, median age 47) underwent MRI to assess tissue sodium levels and water T1ρ values at different spin-locking frequencies in calf muscles. T1ρ values at each locking field were computed based on a three-parameter mono-exponential model to fit signals obtained at different locking times, and R1ρ (=1/T1ρ) rates were compared at different locking fields. In particular, the dispersion of R1ρ (ΔR1ρ=R1ρ(0Hz)−R1ρ(500Hz)) was examined as a function of subject age. Muscle sodium content was calculated by comparing signal intensities between tissues and reference standards within the same image. The variations of ΔR1ρ with age and sodium were analyzed by linear regression. ResultsT1ρ values and sodium content both increased with age. R1ρ dispersion also increased with age and showed a strong linear correlation (correlation coefficient r=0.98, P=0.000578) with sodium content. ConclusionΔR1ρ reports on the contribution of labile protons such as hydroxyls which may be associated with macromolecule accumulation in the extracellular matrix (ECM). An increase of sodium signal suggests an enlarged ECM volume fraction and/or an increase in sodium concentration, which occurs during normal aging. The strong correlation between ΔR1ρ and sodium is likely the consequence of increased ECM and density of total charged sites within the matrix from molecules such as collagens and proteoglycans. The results from this study show the potential use of R1ρ dispersion and sodium imaging in the assessment of pathological changes in muscle such as fibrosis.

Surface complexation modeling of Cu(II) sorption to montmorillonite–bacteria composites

Surface complexation modeling, isothermal titration calorimetry, and batch adsorption were employed to characterize the adsorption of Cu onto montmorillonite, Pseudomonas putida X4, and their composites at mass ratios of 2:1, 6:1, and 12:1, respectively. Different enthalpy values were found for Cu adsorption to permanent (−6.43kJ/mol) and variable charge sites (8.51kJ/mol) on montmorillonite. The component additivity (CA) method was used to predict the adsorption of Cu on the composites by combining end member models for montmorillonite and P. putida. A reduced adsorption was observed at pH<5.5 due to physical blocking between montmorillonite and P. putida. By contrast, the enhanced binding at high pH levels was ascribed to the formation of bridging structures among the clay mineral–Cu–bacteria complexes. These deviations in the CA method were corrected by adding reactions of >RCOOH…XNa and >RCOOCuOHXNa. The increased adsorption of the composites confirmed the decrease of permanent negative charge sites and the formation of ternary complexes. The results help elucidate the effect of Cu adsorption onto clay minerals–bacteria composites. The newly developed “CA–site masking–bridging” model can be used to predict Cu speciation in systems in which the active interaction of bacteria and clay minerals occurs.

Cleaning of pH Selective Electrodes with Ionophore‐doped Fluorous Membranes in NaOH Solution at 90 °C

AbstractThis work demonstrates the remarkable stability of fluorous ion‐selective electrode (ISE) membranes by exposing them to cleaning‐in‐place treatments (CIP) as they are used in many industrial processes. The sensing membranes consisted of Teflon AF2400 plasticized with a linear perfluoropolyether and doped with ionic sites and a H+ ionophore (i. e., tris[3‐(perfluorooctyl)propyl]amine, 1, or tris[3‐(perfluorooctyl)pentyl]amine, 2). To mimic a typical CIP treatment, the electrodes were repeatedly exposed for 30 min to a 3.0 % NaOH solution at 90 °C (pH 12.7). ISE membranes doped with the less strongly H+ binding ionophore 1 started to show reduced potentiometric response slopes and increased resistances after one exposure for 30 min to hot 3.0 % NaOH solution. No decomposition of the ionic sites and ionophore 1 at 90 °C was evident by 1H NMR spectroscopy, suggesting that the performance of membranes doped with 1 was compromised primarily by leaching of the negatively charged ionic sites along with H+ into the hot caustic solution. In contrast, even after ten exposures to hot 3.0 % NaOH for a cumulative 5 h at 90 °C, the fluorous sensing membranes doped with the more strongly H+ binding ionophore 2 still showed the ability to respond with a theoretical (Nernstian) slope up to pH 12. Addition of the fluorophilic electrolyte salt methyltris[3‐(perfluorooctyl)propyl]ammonium tetrakis[3, 5‐bis(perfluorohexyl)phenyl]borate reduced the membrane resistance by an order of magnitude.

The adsorption mechanism of N-butoxypropyl-S-[2-(hydroxyimino) propyl] dithiocarbamate ester to copper minerals flotation

In this paper, a novel surfactant, N-butoxypropyl-S-[2-(hydroxyimino) propyl] dithiocarbamate ester (BOPHPDT) was first synthesized and introduced as a flotation collector for copper minerals. The micro and bench-scale flotation results demonstrated BOPHPDT exhibited superior flotation performance for chalcopyrite in comparison with xanthates and excellent selectivity against pyrite, and the preferable pH values for its attachment to chalcopyrite surfaces were 4–8. Adsorption thermodynamics and kinetics elucidated that BOPHPDT adsorption on to chalcopyrite was a spontaneously endothermic chemisorption process. The results of in situ scanning electrochemical microscopy (SECM) and zeta potential showed that BOPHPDT might anchor on the positively charge sites of chalcopyrite surfaces to form new species. Fourier transform infrared (FTIR) spectra further elucidated that BOPHPDT might react with the Cu atoms of chalcopyrite surfaces through its CNOH and NHC(S) groups. The double chelating groups and multiple hydrophobic chains of BOPHPDT, rendered it to possess excellent affinity and hydrophobicity for improving copper minerals flotation.

Microstructure characterization in direct sheet molding compound

The microstructure of fiber glass bundles used in the direct sheet molding compound (D‐SMC) was investigated in a flat plaque mold. Analyses of the bundle deformation, including bending and deformation of the tow shape, were done for the charge and specific sites within a square plaque part for 30% and 62% of initial charge mold area coverages. Microscopy and micro‐computed tomography (micro‐CT) of the samples clarify the microstructure of the bundles after flow. Samples were taken at different flow locations within the plaque corresponding to increasing flow length from the center. The bundles at the part edge and corner deform more than the bundles close to center of the mold in both initial charge cases. The bundles flattened at all positions and bundle bending was mainly observed at the corner. The tow width changes and tow deflections were higher in the samples of 30% mold area coverage. The micro‐CT images showed that the bundles keep their cohesion and stay straight within the middle of the flow path position, but bend at the edge of the mold. Mold filling simulation using Moldflow™ (Autodesk) predicted fiber tow orientation through the thickness using the reduced‐strain closure (RSC) models for fiber distribution for 30% and 62% initial mold area coverage. The measured value of orientation from micro‐CT images confirms the random orientation through the thickness, consistent with the RSC model. POLYM. COMPOS., 40:E69–E77, 2019. © 2017 Society of Plastics Engineers

Novel insights into the regulation of coagulation by factor V isoforms, tissue factor pathway inhibitorα, and protein S

Factor V (FV) is a regulator of both pro- and anticoagulant pathways. It circulates as a single-chain procofactor, which is activated by thrombin or FXa to FVa that serves as cofactor for FXa in prothrombin activation. The cofactor function of FVa is regulated by activated protein C (APC) and protein S. FV can also function as an anticoagulant APC cofactor in the inhibition of FVIIIa in the membrane-bound tenase complex (FIXa/FVIIIa). In recent years, it has become clear that FV also functions in multiple ways in the tissue factor pathway inhibitor (TFPI) anticoagulant pathway. Of particular importance is a FV splice variant (FV-Short) that serves as a carrier and cofactor to TFPIα in the inhibition of FXa. FV-Short is generated through alternative splicing of exon 13 that encodes the large activation B domain. A highly negatively charged binding site for TFPIα is exposed in the C-terminus of the FV-Short B domain, which binds the positively charged C-terminus of TFPIα, thus keeping TFPIα in circulation. The binding of TFPIα to FV-Short is also instrumental in localizing the inhibitor to the surface of negatively charged phospholipids, where TFPIα inhibits FXa in process that is stimulated by protein S. Plasma FV activation intermediates and partially proteolyzed platelet FV similarly bind TFPIα with high affinity and regulate formation of prothrombinase. The novel insights gained into the interaction between FV isoforms, TFPIα, and protein S have opened a new avenue for research about the mechanisms of coagulation regulation and also for future development of therapeutics aimed at modulating coagulation.

Modeling Flexible Molecules in Solution: A pKa Case Study.

Continuum solvation models have been incredibly successful for the computationally efficient study of chemical reactions in solution. However, their development and application has generally been on focused on investigations of small, rigid molecules. Additional factors must be considered when studying large, flexible and multiply ionizable species. These include whether the use of thermocycle or entirely solution-phase approaches are more appropriate for the calculation of solution-phase free energies, which metrics can be used to reliably identify the conformation(s) adopted by flexible molecules in solution, and how errors due to inaccuracies in the prediction of low energy vibrational frequencies can be avoided. Here we explore these issues using the calculation of pKas for a diverse set of amine-containing species as a case study. We show that thermocycle-based approaches should only be applied where there are relatively small structural changes between the gas- and solution-phase molecular geometries, and that these methods are generally not appropriate for conformational searching. Using gas- or solution-phase energies or gas-phase free energies can also lead to errors in the identification of the most stable molecular conformation(s). Scaling of low energy vibrational modes (i.e., use of the quasi-harmonic oscillator approximation) is helpful, however care must be taken to ensure modes that change as part of the reaction are not disregarded. Entirely solution-phase approaches to the Gibbs free energy and hence pKa calculations were found to yield accurate pKa values for the amine test set studied when each charged site is complexed with an explicit water molecule and a proton exchange scheme is applied with an appropriately chosen reference acid.

Phosphorus adsorption onto clay minerals and iron oxide with consideration of heterogeneous particle morphology

Particle morphology plays an important role in solid-water interface adsorption, which affects the fate and behavior of phosphorus (P) in rivers and lakes and the resulting eutrophication. In this paper, three minerals including kaolinite, montmorillonite and hematite were considered to investigate the contributions of particle morphology to P adsorption using adsorption experiments and microscopic examinations. The Taylor expansion method is applied to quantitatively characterize the heterogeneity of surface morphology. The results reveal that local concave or convex micro-morphology characterized by the second order term of Taylor expansion F2, can affect the local adsorption capacity due to its effect on the distribution of surface charge and reactive sites. Moreover, the adsorbed P at different F2 here fits to a Weibull distribution, which can further define the representative average adsorption onto individual particles. A weighted average morphology factor F2a is derived to characterize the surface heterogeneity, and correlated with average P adsorption of particular mineral particles. In addition, the Sips model can successfully fit the experimental data of different minerals, and the heterogeneity parameters γ and adsorption capacity Qm in the model are proved to be functions with the basic mineral properties, including particle size, surface site density and morphology characterization as well. It is concluded that the complex surface morphology plays a significant role in particle adsorption and the morphological role need to be considered in the adsorption model in order to better describe the adsorption in system with heterogeneous solid surface.