Clay Composites Research Articles

Development of clay ferrite nanocomposite: Electrochemical, sensors and photocatalytic studies

Nano ferrite bentonite clay composite (NFBC) is synthesized in this present work by using manganese (Mn) recovered from waste batteries, ferric nitrate and citric acid prepared by simple and cost-effective Indian sodium bentonite nanoclay (Na-IB) by sol-gel process and by using X-ray diffractrometer (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) Spectroscopy, Energy dispersive Spectroscope (EDS) characterized nanoparticles. The result shows that NFBC is sufficient for the excellent performance of AO dye photocatalytic degradation (98 %). Electrochemical study of prepared material with graphite electrode paste in 0.1 M KCl electrolyte showed excellent redox potential output as calculated by cyclic voltammetry and expanded its sensor activities to biochemical (Dextrose). We examined the efficacy of NFBC in the detection of Dextrose from an aqueous solution and compared the results with pristine MnFe2O4 NPs.

The potential application of cement kiln dust-red clay brick waste-silica fume composites as unfired building bricks with outstanding properties and high ability to CO2-capture

In this paper, a simple eco-sustainable approach was applied to synthesize unfired building bricks, in which cement kiln dust (CKD), red clay brick waste (RCBW), and silica fume (SF) were the main ingredients. The CKD-RCBW-SF composite was adjusted at different weight ratios of 50-50-0, 50-40-10, 50-30-20, and 50-20-30 wt%. The fabrication process included three main stages, i.e. dry blending, water mixing, and casting. Different curing conditions were applied (water, air, and CO2-gas) to assess the effect of curing type on the performance of the prepared bricks. The results demonstrated that increasing SF content caused an increase in compressive strength escorted by a significant decrease in bulk density of the hardened bricks, regardless of curing type. All over of the curing media, the hardened samples cured in water showed the highest performance. The highest 28-days compressive strength value (47 MPa) was achieved by hardened CKD-RCBW-SF composite (at a weight ratio of 50-20-30 wt%, respectively) cured in water. Unlike its effect on the physical and mechanical performances, increasing SF content negatively influenced the capability of the hardened bricks to CO2-sequestration. Specifically, the hardened bricks with no SF cured in CO2 gas for 28-days can sequestrate higher CO2 content (~75 kg/ton) compared to the hardened samples containing 30 wt% SF (~59 kg/tonne). The proposed method is not only considered as an innovative approach for mitigating CO2 emission resulted from the traditional bricks industry, but also strongly contributed to waste disposal, the conservation of the reserve of natural materials, the decrease of energy demand and processing cost, and the enhancement of the ability of the hardened bricks to CO2-capture.

Characterization of train brake-blocks composite reinforced with aluminum-dross

Brake blocks are usually made from asbestos, metals and ceramics. It has been realised that asbestos discharges dangerous gases which can be harmful. This problem necessitated the search for human-friendly materials. Therefore, this paper studies the production and characterization of train brake blocks produced from clay reinforced with aluminum dross. This was done by producing samples of composite using clay from a deposit at Osiele and aluminum dross from Tower Rolling Mill Otta, both in Ogun state. The percentage composition of aluminum dross was varied from 0% to 25% to produce brake samples. Their wear rate, tensile strength, compressive strength, hardness, thermal conductivity and microstructure were analysed. The results from this project such as Ultimate tensile strength (UTS) of 7.4Mpa, Impact energy 6.92J, Hardness 28.8 HV, wear rate 0.0071g/sec and thermal conductivity of 0.01075 indicate that, with 5% aluminium dross it is possible to develop brake block that exhibits property recommended by Rail Industry Safety and Standard Board (RISSB).
 Keywords: Train, Brake blocks, Clay composite, Aluminum Dross, Mechanical properties.

Chitosan–Clay Composites for Wastewater Treatment: A State-of-the-Art Review

In recent decades, increased domestic and industrial activities have led to the release of various pollutants into the aquatic environment. A robust and eco-friendly technique for removing these po...

Single-route delaminated clay composites for efficient visible-light photo-mineralization of antibiotic-resistant bacteria and associated genes in water

Drinking water contaminated with antibiotic resistant bacteria could result in loss of antibiotic effectiveness in humans, increased healthcare cost and ultimately death. New delaminated photocatalytic composite (DPC) has been prepared. DPC doped with Cu/Zn kept multidrug resistant (MDR) E. coli and its sulphonamide resistance genes in contaminated water at log reduction >6 for 36 h in two disinfection steps under visible-light using fixed-bed mode (downward flow). In contrast, fluoroquinolone resistance genes persisted in treated water after the first disinfection step and were significantly reduced after the second disinfection step. Surface oxygen vacancies were mainly responsible for photoactivity of DPC. No bacteria re-growth was observed in treated water stored in light/dark for 7 days. A 95 % photo-mineralisation of MDR E. coli and its genes was achieved via the release of superoxide radical (in dark/light). Shelf-life study of DPC vs non-delaminated photocatalytic composite over 7 months suggests that the former remained far more efficient than the latter.

A review on the mechanical strength of aluminium - clay composites

The innovation in the usage of cheaper materials with better quality has been in the mind of many scientists. Recently, more requests have been on the utilization of agro-industrial product to produce materials to curb ecological hazards. Clay could be an alternative to SiC and Al2O3 due to their cheaper rate and availability. Reinforcements can be integrated into the melt using cheap and globally recognized stir casting method. Low - cost eco-friendly waste products that are easily accessible like clay, nanoclay, kaolinite, mica, and carbon are utilized as reinforcement in aluminium alloy. This review paper studied the various compositions of aluminium alloy composites for manufacturing purposes and its usage in automobile, aircraft, marine and the transportation industry. The study revealed that the addition of clay as reinforcement increases the properties of the composites.

Efficiency of natural clay and titania P25 composites in the decolouring of methylene blue (MB) from aqueous solutions: dual adsorption and photocatalytic processes

In this paper, we use Tunisian clay materials as alternative low-cost adsorbents, as well as substrates to immobilise TiO2 for the decolouration of methylene blue (MB) dye solutions. The collected raw clay from the mine of Tamra was characterised by various techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray fluorescence (XRF). XRD patterns of the raw clay showed halloysite as the main phase (61%), with a lower content of kaolinite (39%). For MB adsorption, the experimental data were fitted by Langmuir and Freundlich adsorption equations. It was found that the studied clays alone were not very efficient at adsorbing MB dye molecules. The decolouration of MB was improved by adding a photocatalytic function to the clay, by adding various amounts of TiO2 nanopowder (20–80 wt%) to the clay, imbuing it with photocatalytic capabilities. These combined effects of the phenomena of adsorption and photocatalysis for MB removal by the TiO2-doped clay resulted in a very satisfactory performance, even with the relatively low quantity of 20 wt% added TiO2 photocatalyst. This gave 48.6% removal after only 30-min adsorption in the dark, increasing to 84.1% removal after a further 3 h under UV light, through combined chemo-physical adsorption and photocatalytic decolouration phenomena.

2D LDH-MoS2 clay nanosheets: synthesis, catalase-mimic capacity, and imaging-guided tumor photo-therapy

Owing to the hypoxia status of the tumor, the reactive oxygen species (ROS) production during photodynamic therapy (PDT) of the tumor is less efficient. Herein, a facile method which involves the synthesis of Mg–Mn–Al layered double hydroxides (LDH) clay with MoS2 doping in the surface and anionic layer space of LDH was presented, to integrate the photo-thermal effect of MoS2 and imaging and catalytic functions of Mg–Mn–Al LDH. The designed LDH-MoS2 (LMM) clay composite was further surface-coated with bovine serum albumin (BSA) to maintain the colloidal stability of LMM in physiological environment. A photosensitizer, chlorin e6 (Ce6), was absorbed at the surface and anionic layer space of LMM@BSA. In the LMM formulation, the magnetic resonance imaging of Mg–Mn–Al LDH was enhanced thanks to the reduced and acid microenvironment of the tumor. Notably, the ROS production and PDT efficiency of Ce6 were significantly improved, because LMM@BSA could catalyze the decomposing of the overexpressed H2O2 in tumors to produce oxygen. The biocompatible LMM@BSA that played the synergism with tumor microenvironment is a promising candidate for the effective treatment of cancer.

Computational and experimental assessment of pH and specific ions on the solute solvent interactions of clay-biochar composites towards tetracycline adsorption: Implications on wastewater treatment

Experimental and computational investigations have been conducted in this study to assess the influence of municipal waste pyrolyzed biochar impregnated clay composites on antibiotic removal as a material for wastewater treatment and simultaneous value-addition for waste. The surface potential (zeta potential) of the pristine biochar and composite samples are found to be within the range ~10 to ~ −40 mV in the pH range 2–10. The presence of different inorganic salt solutions influences the electrophoretic mobility of the dispersed phase in a suspension, as well as its zeta potential. In addition of Na+ salt solutions, the Na+ ions undergo electrostatic interaction with the negatively charged biochar samples and form a double layer at the interface of biochar and ionic salt solution. Molecular dynamics simulations have been employed to understand experimental findings, ions adsorption and solute-solvent interactions at the molecular level of two biochar B7 (seven benzene rings, one methoxy, one aldehyde and two hydroxyls groups) and B17 (seventeen benzene rings, one methoxy, two hydroxyls and two carboxylic acid groups) in salts aqueous solutions. The results confirm that hydroxyls and carboxylate groups of biochar are responsible for solute-solvent interactions. Successful removal of tetracycline antibiotics is observed with 26 mg/g maximum adsorption capacity with montmorillonite biochar composite. This study confirms that interactions between amide and hydroxyl groups of tetracycline with hydroxyl and carboxylate groups of biochar play the key role in the adsorption process. The solution pH and presence of different background electrolytes effectively influence the process of solute-solvent interactions as well as adsorption efficacy towards tetracycline adsorption.

Two-dimensional clay nanosheet-reinforced polytetrafluoroethylene composites and their mechanical/tribological studies

Polytetrafluoroethylene (PTFE) polymer is used extensively in industry as a solid lubricant because of its lack of reactivity with most industrial materials. However, PTFE has a low abrasive resistance, limiting its application. In this study, the mechanical and tribological characteristics of PTFE-based composites with the addition of clay nano-sheets (CNSs) were investigated. Clay nano-sheet-PTFE composites (CNSTCs) containing 1, 3, and 5 wt. % of CNSs were prepared by employing a compression moulding method. To investigate the tribological characteristics and wear mechanism of CNSTCs, a pin-on-ring test, scanning electron microscopy (SEM), and optical microscopy (OM) were employed. The results indicate that adding CNSs decreased the friction coefficient substantially. Additionally, the wear rates decreased from 1.09 × 10−3 mm3/(Nm) in the pure PTFE sample to 0.32 × 10-5 mm3/(Nm) for the 5 wt. % CNSs filled composite. This shows that the wear rate of the PTFE-based composite is reduced by up to 340 times with the addition of 5 wt. % CNSs. SEM and OM observations revealed that CNSs could inhibit the growth of microcracks in CNSTCs and change the wear mechanism from adhesive to abrasive. Furthermore, adding CNSs resulted in a more uniform and thinner transition film formation, with reduced secondary wear and friction. The effects of the size, percentage, and type of embedded fillers were compared with previous studies. The analysis revealed that in addition to competitive cost and high availability, CNSs have superior characteristics and can be employed to enhance the tribological properties of PTFE nanocomposites.

Acoustic Panels Made of Paper Sludge and Clay Composites

Studies on recycled materials emerged during recent years. This paper investigates samples’ sound absorption properties for panels fabricated of a mixture of paper sludge (PS) and clay mixture. PS was the core material. The sound absorption was measured. We also consider the influence of an air gap between panels and rigid backing. Different air gaps (50, 100, 150, 200 mm) simulate existing acoustic panel systems. Finally, the PS and clay composite panel sound absorption coefficients are compared to those for a typical commercial absorptive ceiling panel. The average sound absorption coefficient of PS-clay composite panels (αavg. in the frequency range from 250 to 1600 Hz) was up to 0.55. The resulting average sound absorption coefficient of panels made of recycled (but unfinished) materials is even somewhat higher than for the finished commercial (finished) acoustic panel (αavg. = 0.51).

Radiation-Induced Improving Mechanical and Thermal Properties of Carboxymethyl Cellulose/Clay Composite for Application in Removal of Copper(II) Ions from Wastewater

A study was carried out on the effect of gamma irradiation on the mechanical and thermal properties of carboxymethyl cellulose (CMC)/Ca-montmorillonite clay composite, prepared by blending using solvent method. In this study, carboxymethyl cellulose was used as a hosting matrix where clay was added to there at different contents: 0.25, 0.5, 1, 1.5 wt%, as a filler. The polymer composite films were cross-linked by irradiation with different integral doses. The results showed that the tensile strength (TS) increased continuously with radiation dose up to 10 kGy, beyond which declined. Meanwhile, TS exhibited increases with clay load ratio. However, the elongation at break (Eb) decreased continuously with dose and clay percentage within the developed composite films. Variation in structure and thermal properties were studied using X-ray diffractometion (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) techniques. The produced CMC/clay composites were implemented in removing copper (II) ions from a synthesized wastewater. The isotherm models and kinetic studies for the adsorption of Cu (II) onto CMC/clay were carried out. The results revealed that 0.1 g fabricated composite film irradiated at 10 kGy significantly removed copper (II) ions with adsorption capacity of 54.6 mg/g at optimum conditions: pH = 5, contact time = 300 min.

Rod-plate interactions in sepiolite-LAPONITE® gels: microstructure, surface chemistry and rheology.

Pure and composite clay gels of sepiolite and LAPONITE® at 4 wt% solids were characterised microstructurally and rheologically. They all displayed time-dependent behaviour, i.e. yield stress increased with aged time. The microstructures captured by cryo-SEM on the samples prepared by high pressure and rapid freezing showed the presence of bonding between LAPONITE® sheets and sepiolite fibres. These bonds are likely to be formed between the positive sheet edge and the negative fibre silica face as suggested by the upright orientation adopted by most LAPONITE® sheets. The sheets formed isolated open networks at a low content and a continuous open network at a high content. The fibres of the pure sepiolite gel formed a relatively strong network. However, the composite networks formed at a low LAPONITE® content between 5 and 25% must be discontinuous as the yield stress is zero. At a higher LAPONITE® content, the composite structure displayed increasing strength. The time-dependent ageing behaviour is due to the electric double layer (EDL, face-face) repulsive force governing the development of the 3D network structure. The Leong model described this behaviour well. All the clay gels displayed a maximum yield stress at a pH of 9 to 10. Pyrophosphate additive reduced the maximum yield stress and shifted the yield stress-pH curve to a lower pH. The Herschel-Bulkley model described the flow behaviour of all the gels well. The variation of the model yield stress with gel composition is similar to that obtained by the vane yield stress technique.

Simultaneous recovery of ammonium and total phosphorus from toilet tail water by modified palygorskite-bentonite clay.

Suitable treatment of toilet sewage is a worldwide challenge. The anaerobic baffled reactor (ABR)-microbial fuel cell (MFC)-microbial electrolysis cell (MEC) (AMM) coupling treatment system has been constructed achieving effective removal of carbon, nitrogen, and phosphorus from toilet sewage and resource recovery; however, ammonium (NH4 + -N) and total phosphorus (TP) accumulation in tail water is a found problem of the system. In this study, acid-modified and alkali-heat modified palygorskite-bentonite (Pal-Ben) were used to recover NH4 + -N and TP from the AMM toilet tail water simultaneously. The higher adsorption capacity of the modified clay is attributed to the changes of surface structure of the material. The modified clay Pal-Ben (mass ratio 1:3) activated with alkali performed the highest NH4 + -N and TP recovery rates of 83.6% and 85.5%, respectively. The adsorption of NH4 + -N was more in line with the pseudo-second-order kinetic model and confirmed to be a chemical adsorption process, while the adsorption of TP was more in line with the pseudo-first-order kinetics and a physical adsorption process; the adsorption capacity of NH4 + -N accelerated with decrease of TP removal when pH increased. This study developed a low cost and high capacity of alkaline thermally modified clay removing/recovering NH4 + -N and TP from toilet tail water simultaneously. PRACTITIONER POINTS: A cheap composite clay was developed to recover nitrogen and phosphorus from toilet tail water simultaneously. The low costs and high capacity of alkaline thermally modified clay make it stand out in NH4 + -N and TP removal of toilet tail water. The process mechanism of simultaneous nitrogen and phosphorus recovery was clarified with characterization and kinetic model fitting. The used clay loaded with nutrients could be applied as a slow-release compound fertilizer for soil improvement.

Experimental and theoretical studies of Rhodamine B direct dye sorption onto clay-cellulose composite

Dyes are one of the main water pollutants and many biological and environmental problems are associated with them. Rhodamine B (RhB) is one of the most commonly used dye in the textile, printing, paints, and paper industry. The present work reports the sorptive removal of Rhodamine B direct dye from wastewater onto developed cellulose and clay composites. Sorbent material cellulose (48 g) was extracted from 80 g of bagasse. Then cellulose and two types of acid-activated clays were used to make efficient sorbent namely, composite I and II. Various characterization techniques were used to study the physiochemical properties of the synthesized composites. Different sorption affecting parameters were optimized such as initial dye concentration, time, temperature, pH, and composite dose for the efficient sorption of RhB onto composites. Equilibrium time was 60 min for composite-I and 80 min for composite-II Non-linear equilibrium isotherm and kinetic models demonstrated the fitness of Pseudo-second order and Redlich-Peterson isotherm. Composite-I and II removed 85.9% and 95.6% of RhB at pH 2 in 120 min, respectively. The sorption efficiency was checked, and sorbents were applied to real textile effluent which showed promising removal efficiency of over 90%. To confirm the experimental results, computational optimization and vibrational calculations were carried out using the Gaussian 09 program package with 3–21 G, 6–311 G, and 6–311+G basic sets. Geometric parameters showed the planar geometry. In the case of FTIR spectra, fundamental ring vibrations were observed with C-H and C-C. This study suggests that the developed composites have exceptional sorption ability to remove the dye contents from aqueous media.

A New Long-Term Composite Drug Delivery System Based on Thermo-Responsive Hydrogel and Nanoclay.

Several problems and limitations faced in the treatment of many diseases can be overcome by using controlled drug delivery systems (DDS), where the active compound is transported to the target site, minimizing undesirable side effects. In situ-forming hydrogels that can be injected as viscous liquids and jellify under physiological conditions and biocompatible clay nanoparticles have been used in DDS development. In this work, polymer–clay composites based on Pluronics (F127 and F68) and nanoclays were developed, aiming at a biocompatible and injectable system for long-term controlled delivery of methylene blue (MB) as a model drug. MB release from the systems produced was carried out at 37 °C in a pH 7.4 medium. The Pluronic formulation selected (F127/F68 18/2 wt.%) displayed a sol/gel transition at approx. 30 °C, needing a 2.5 N force to be injected at 25 °C. The addition of 2 wt.% of Na116 clay decreased the sol/gel transition to 28 °C and significantly enhanced its viscoelastic modulus. The most suitable DDS for long-term application was the Na116-MB hybrid from which, after 15 days, only 3% of the encapsulated MB was released. The system developed in this work proved to be injectable, with a long-term drug delivery profile up to 45 days.

Design and synthesis of PVDF-cloisite-30B nanocomposite fibers for energy harvesting applications

Polymer nanofibers of PVDF/Cloisite-30B clay composites were synthesized by far field electrospinning technique. Taguchi's L9 orthogonal array was used to study the effect of process parameters in electrospinning. Different polymer composite films were prepared with various composition and process parameters. The best result obtained with highest β-phase crystallinity with 89.7% with average fiber diameter of 79 nm. Further piezoelectric property of nanofiber composite was measured by oscilloscope actuated through a mechanical cam driven by a D C motor at different speed 500, 1000 and 1500 rpm respectively. Grey relation analysis was performed to identify the most significant process parameters for preparation of uniform nanofibers. Grey relation grading for response parameters was ranked 1 for highest β-phase crystallinity among the studied composites. The PVDF composite sample with 3% cloisite-30B showed high instantaneous voltage of 4.4V with applied voltage of 22 kV and collector plate distance of 12 cm.

Experimental analysis and parametric optimization of drilling process for ferrous clay composite using GRA-PCA approach

The use of materials mixture with non-metallic ingredients composed by powder metallurgy (PM) are getting increased attention in many industries. The newly developed composite material is mainly applied to the structural parts in the many industries. PM parts machining is still a challenge and known as difficult-to-cut metals for manufacturers because of the many factors mainly porosity, Nano particles and complex microstructure. In this work, the mechanical properties like density and porosity along with the machinability in drilling of a newly developed sintered powder metallurgy (P/M) components having Nano-particles of bentonite clay as machinability enhancer is evaluated by a standard twist drill. The impact of this paper aims to reveal the key cutting phenomena i.e. generation of thrust forces, quality of surface roughness, and new insight into the machining mechanism of sintered material. The parameters involved in the machinability study are as speed, feed rate and Nano-particles of bentonite clay for controlling the parametric variables on the response parameters. The speed has the major (95%) effect on the thrust force where the clay percentage has the major (84%) effect on the surface roughness. The less thrust force and low surface roughness have been achieved at 5% clay with 910 rpm and 1% clay with 2265 rpm, respectively. Further, the hybrid grey relational analysis along with principal component analysis (GRA-PCA) has been carried out to find the optimum condition. The less thrust force (Ft) and low surface roughness (Ra) has been found at 1% clay and 910 rpm. The confirmation of optimal process parameters has been made with overall evaluation criteria (OEC) and found the same optimum condition. The X-ray diffraction despises homogeneous mixture of clay in ferrous clay composite. The SEM analysis exposed the presence of clay particles and plastically deformed area during drilling of ferrous clay composite. Thus, this analysis show that the 1% of Nano-particles of bentonite clay is helpful as porosity fillers or machinability enhancer at low speed and within acceptable mechanical properties.

Simultaneous adsorption and degradation of bisphenol A on magnetic illite clay composite: Eco-friendly preparation, characterizations, and catalytic mechanism

Excess bisphenol A (BPA) is a pollutant of concern in different water sources. In this work, magnetic illite clay-composite material (Fe3O4@illite) was synthesized via the coprecipitation method by loading Fe3O4 nanoparticles (nano-Fe3O4) onto the surfaces of illite clay. Results from different characterizations showed that nano-Fe3O4 was embedded into illite clay nanosheets and existed on the surfaces of illite clay, thereby reducing the degree of agglomeration and improving dispersibility. The catalytic BPA degradation of Fe3O4@illite and nano-Fe3O4 confirmed the superior performance of Fe3O4@illite compared with that of nano-Fe3O4. The optimum operating parameters for degradation were 0.3 mL of H2O2 at pH of 3 in the presence of Fe3O4@illite, which provided a maximum degradation capacity up to 816, 364, 113, and 68 mg/g for epoxy BPA concentration of resin wastewater (266 mg/L), synthetic wastewater (80 mg/L), Hefei City swan lake (25 mg/L), and Hefei University lake wastewater (14.94 mg/L), respectively, in 180 min reaction time. The degradation data conformed to the pseudo-first-order kinetic model. The degradation pathways and mineralization study revealed that the adsorption-Fenton-like reaction was the principal mechanism that demonstrated 100% degradation efficiency of Fe3O4@illite even after nine successive runs. The regeneration and reusability tendency analysis ensured that Fe3O4@illite can be easily separated by using magnets. Therefore, Fe3O4@illite composite with H2O2 Fenton-like technology was a promising method for BPA degradation.

Synthesis of zinc oxide nanoparticles reinforced clay and their applications for removal of Pb (II) ions from aqueous media

The aim of the study was to synthesize zinc oxide nanoparticles (ZnONPs) composite with clay by a novel route and then to explore the capability of composite of ZnONPs and silty clay (SC) as adsorbents for Pb (II) eradication from aqueous media by batch adsorption method. The effect of different operating factors like temperature, pH, dose and time of contact on the adsorption process were studied to optimize the conditions. Langmuir, Freundlich, Dubinin–Radushkevich (D-R) and Temkin isotherms were applied for the interpretation of the process. The R2 and q values obtained from Langmuir model suggested that the process is best interpreted by this model. The values of adsorption capacity (qm) noted were 12.43 mg·g−1 and 14.54 mg·g−1 on SC and ZnONPs-SC respectively. The kinetic studies exposed that pseudo second order (PSO) kinetics is followed by the processes suggesting that more than one steps are involved to control the rate of reactions. Various thermodynamic variables such as change in free energy (ΔGϴ), change in enthalpy (ΔHϴ) and change in entropy (ΔSϴ) were calculated. Thermodynamic data suggested that Pb (II) adsorption on SC and ZnONPs-SC are spontaneous, endothermic and feasible processes.