Brunauer, Emmett And Teller Surface Area Research Articles

Co‐generation and GHG emission from agricultural waste based on pyrolysis/gasification: Experimental and LCA approaches

AbstractIn this study, co‐generation from rice straw based on pyrolysis and gasification was studied by experimental and modeling approaches. Pyrolysis experiment results show that improving pyrolysis temperature will benefit the yield of gas and bio‐oil, while reducing the yield of bio‐char. The BET (Brunauer, Emmett, and Teller) surface area of bio‐char reached a maximum of 143.26 m2/g when the temperature was increased to 550°C. For co‐generation in this study, an optimized pyrolysis temperature of 500°C was selected. With respect to gasification, air equivalence ratio (ER) largely influenced the syngas yield and composition. At ER = 0.25, the concentration of H2 and CO reached a maximum of 17.8 wt% and 16.2 wt%. Based on the experimental results, an Aspen Plus model was built to evaluate the mass and energy balance during co‐generation. Furthermore, a life cycle assessment method was used to evaluate the greenhouse gas emission during co‐generation process initialed from rice straw planting. Results show that the greenhouse gas emission intensities of the two co‐generation systems were 2.92 and 3.51 g CO2/MJ respectively, which were much lower than traditional fossil fuels.

Adsorption behavior of trace elements of 90Sr on MnO2–ZrO2 loaded with polyacrylonitrile polymer from aqueous solutions

A MnO2–ZrO2-polyacrylonitrile (MnO2–ZrO2-PAN) composite ion exchanger was produced and its properties were examined by Fourier-transformed infrared spectroscopy, scanning electron microscopy, The BET (Brunauer, Emmett and Teller) surface area, X-Ray diffraction analysis and thermogravimetric analysis. The adsorption of Strontium (Sr) from solutions by MnO2–ZrO2-PAN composite was studied thru batch experiments. The distribution Coefficient of Sr (II) on the composite sorbent was investigated against pH, interaction time, and primary concentration ion. To study the kinetics of adsorption, Pseudo-first-order and Pseudo second-order adsorption kinetics were studied and the results revealed that adsorption kinetics better fit to the pseudo-second-order model. Three iso-temperature models, Langmuir, Freundlich, and Temkin were applied to fit the experimental results. Among those models, Langmuir revealed the most suitable one with minimum deviation. The created composite exhibited strong compatibility to the elimination of Y (III), Ni (II), Pb (II), and Co (II) from radioactive waste streams. On the other, it is evident from the data that the quantifiable extraction of Sr (II) ions from Zr (IV), Mo (VI), and La (III) is feasible. MnO2–ZrO2 Loaded with (PAN) Polymer was figured out to have high ion exchange capacity and thermal stability and selectivity for strontium.

Influence of nanopores volumes in hydrogen absorption properties of B4C and WC carbide-derived carbon nanomaterials

Sustainable energy development is needed to meet rising energy demands and reduce fossil fuel risks. Hydrogen generation is a crucial study area for sustainable energy. This study examines hydrogen adsorption on carbide-derived carbon nano-porous (CDC nP) nanomaterials. B4C CDC nP and WC-CDC nP Nanomaterials were produced by reacting chlorine gas with boron carbide (B4C) and tungsten carbide (WC) at 1200 °C and 980 °C in a high-pressure quartz stationary bed reactor. A CDC nP Nanomaterials was activated by heating it to 900 °C for 1 h in hydrogen to produce A-B4C-CDC nP Nanomaterials, which were characterized using Small-angle X-ray scattering (SAXS), nonlocal density functional theory (NLDFT), X-ray diffractometers (XRD), transmission electron microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), energy dispersive spectroscopy (EDS), and Scanning Electron Microscopy. Before treatment, the BET (Brunauer, Emmett, and Teller) surface area of activated B4C CDC nP material was 2240 m2/g, non-activated WC-CDC nP was 1240 m2/g, and A-B4C-CDC Nanomaterials was 1580 m2/g. This novel study examines CDC pore size and absorption on CDCs. Nitrogen adsorption isotherms showed better pore volume and distribution than raw material. High linearity allows an incompressible adsorbed hydrogen phase at ambient temperature. The isotherms match IUPAC (International Union of Pure and Applied Chemistry) Type I isotherms and confirm nano-porous materials. The equal temperature matches IUPAC Type I isotherms, indicating nano-porous material. H2 adsorption of Sample A peaked at 6.75 wt% at pressures above 125 MPa. Since all three carbide-derived carbons had the same maximum adsorbate density, overall pore volume is a major determinant.

Solvothermal synthesis of organoclay/Cu-MOF composite and its application in film modified GCE for simultaneous electrochemical detection of deoxyepinephrine, acetaminophen and tyrosine.

An organoclay/copper-based metal-organic framework (MOF) composite was synthesized using a solvothermal method by growing a Cu-BTC (copper(ii) benzene-1,3,5-tricarboxylate) MOF from a mixture of the MOF precursor solution in which various amounts of organoclay had been dispersed. The organoclay was obtained by intercalating a cationic dye, namely thionin, into a natural Cameroonian clay sampled in Sagba deposit (North West of Cameroon). The organoclay and the as-synthesized composites were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and Brunauer, Emmett and Teller (BET) techniques. From Scherrer's equation, the crystallite size of the composite was found to be between 55 and 58 nm, twice as large as the pristine MOF's crystallite size. The organoclay/Cu-MOF composite (Sa-TN50/Cu3(BTC)2) exhibiting a BET surface area of 192 m2 g-1, about twice that of pristine clay and about one seventh that of pristine MOF, was then utilized to form a stable thin film onto glassy carbon electrodes (GCE) by drop coating (Sa-TN50/Cu3(BTC)2/GCE). These electrodes demonstrated electrocatalytic behavior toward deoxyepinephrine (DXEP) and thus enabled selective and simultaneous sensitive detection of three analytes: DXEP, acetaminophen (AC) and tyrosine (TYR) compared with bare GCE and clay modified electrode. Under optimum conditions, Sa-TN50/Cu3(BTC)2/GCE exhibited good performance including large calibration curves ranging from 5.0 μM to 138.0 μM for DXEP, 4.0 μM to 153.0 μM for AC and 1.0 μM to 29.4 μM for TYR. The detection limits were found to be, 0.4 μM, 0.7 μM and 0.2 μM for DXEP, AC and TYR, respectively. The developed sensors have been applied successfully in the quantification of AC in a commercial tablet of AC, and DXEP, AC and TYR in tap water.

Multiple structure graphite stabilized stearic acid as composite phase change materials for thermal energy storage

This paper used 3 types of graphite with different physical structures as the porous matrix to prepare composite phase change materials (PCMs), and investigated their photo-thermal conversion performance and application in battery thermal management. Multiple structure graphite minerals, including microcrystalline graphite (MG), scale graphite (SG), and expanded graphite (EG) were used as porous matrix, while stearic acid (SA) acts as the phase change material. The vacuum impregnation method was applied to prepare SA/MG, SA/SG, SA/EG, and SA/MG1, and SA/EG1was/were prepared by the ethyl alcohol method. Results show that the thermal conductivities of all composite phase change materials were 10.82 to 22.06 times higher than that of the pure SA. Thermogravimetric (TG) analysis showed that the loadages of SA were 43.61%, 18.74%, and 92.66% for SA/MG, SA/SG, and SA/EG respectively. The load rates of SA were 18.98% and 18.88% for SA/MG1 and SA/EG1, respectively. For the 3 types of graphite materials of different dimensions, the BET (Brunauer, Emmett, and Teller) surface area determines the maximum load of SA. The Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) results indicated that there was good compatibility between the SA and the supports. The SA/EG1 has better thermophysical properties in heat energy storage and release process. The thermal infrared images show that SA/EG1 has higher sensitivity to the temperature changes. SA/EG1 has better photo-heat conversion performance than SA/SG and SA/MG1 attributed to the multilayer structure of EG. SA/EG has better thermal management performance in the Li-ion batteries discharge process.

Comparative assessment of the biomass solar pyrolysis biochars combustion behavior and zinc Zn(II) adsorption

Biochars from solar pyrolysis of the waste straw, and dried sewage sludge, were assessed to recognize the possible application as unconventional adsorbents and fossils replacements for combustion purposes. The adsorption properties of the biochars were characterized by the BET (Brunauer, Emmett, and Teller) surface area, pore volumes, and the degree of Zn(II) adsorption from aqueous solutions. A higher removal degree of zinc ions of 26% was noted for biochars from dried sewage sludge with a BET area of 40.84 m2/g, compared to the waste straw biochars with a BET area of 1.67 m2/g and a corresponding removal degree of 16%. Both biochars presented more uniform combustion behavior compared to raw biomass, with the ignition and burnout temperatures similar to coal. Solar pyrolysis caused a reduction of the combustion kinetic steps, from multi-step combustion of the raw biomass to a single-step and two-step kinetic mechanisms for the sewage sludge and waste straw biochars respectively. It was found that the waste straw biochars are possible alternative fuels with a higher heating value of 22.6 MJ/kg, while sewage sludge chars presented better zinc adsorption of 2.09 mg/g and a total removal degree of 26%.

Electrospun Composite Nanofiltration Membranes for Arsenic Removal

In recent years, significant attention has been paid towards the study and application of mixed matrix nanofibrous membranes for water treatment. The focus of this study is to develop and characterize functional polysulfone (PSf)-based composite nanofiltration (NF) membranes comprising two different oxides, such as graphene oxide (GO) and zinc oxide (ZnO) for arsenic removal from water. PSf/GO- and PSf/ZnO-mixed matrix NF membranes were fabricated using the electrospinning technique, and subsequently examined for their physicochemical properties and evaluated for their performance for arsenite–As(III) and arsenate–As(V) rejection. The effect of GO and ZnO on the morphology, hierarchical structure, and hydrophilicity of fabricated membranes was studied using a scanning electron microscope (SEM), small and ultra-small angle neutron scattering (USANS and SANS), contact angle, zeta potential, and BET (Brunauer, Emmett and Teller) surface area analysis. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to study the elemental compositions and polymer-oxide interaction in the membranes. The incorporation of GO and ZnO in PSf matrix reduced the fiber diameter but increased the porosity, hydrophilicity, and surface negative charge of the membranes. Among five membrane systems, PSf with 1% ZnO has the highest water permeability of 13, 13 and 11 L h−1 m−2 bar−1 for pure water, As(III), and As(V)-contaminated water, respectively. The composite NF membranes of PSf and ZnO exhibited enhanced (more than twice) arsenite removal (at 5 bar pressure) of 71% as compared to pristine PSf membranes, at 43%, whereas both membranes showed only a 27% removal for arsenate.

Influence of Pyrolysis Temperature on the Heavy Metal Sorption Capacity of Biochar from Poultry Manure.

Sorption properties of various biochars have been extensively investigated by many researchers. One of the parameters that have a significant impact on sorption properties is pyrolysis temperature. This paper presents a study on the effect of pyrolysis temperature (425, 575, 725 °C) on the sorption properties of poultry-manure-derived biochar (BPM). The produced biochars, i.e., BPM425, BPM575 and BPM725, demonstrated specific properties at 425, 525 and 752 °C such as high pH (10.40, 10.65 and 12.45), high ash contents (52.07, 61.74 and 78.38%) and relatively low BET (Brunauer, Emmett and Teller) surface area (11, 17 and 19 m2·g−1). The analysis of the mineral phases of the BPMs confirmed the buffering capacity. The investigated biochars were tested for sorption of Zn, Cd and Pb in mono-, double- and triple-metal batch sorption tests. According to the obtained results, biochar produced at a temperature of 575 °C (BPM575) can function as a sufficient sorbent for the removal of Zn, Cd and Pb from a water solution. The presented results do not confirm the effect of competing metal ions on the sorption efficiency of the selected metals by the investigated biochars. Based on that, the studied biochar sorbents can be used in environments contaminated with many metals.

Sonocatalytic degradation of amoxicillin from aquaculture effluent by zinc oxide nanoparticles

In this study, zinc oxide nanoparticles (nano-ZnO) was effectively synthesised by precipitation method to catalyse the ultrasound degradation of amoxicillin aquaculture effluent. The nanoparticles at different calcination temperatures were characterised by scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, x-ray diffraction, and Brunauer, Emmett and Teller (BET) surface area determination. Characterisation results indicated that Zn existed as different compounds at different temperature, besides, pure zincite (ZnO) was obtained at 500 °C having a BET surface area of 8.39 m2/g. The degradation experiments indicated that the ultrasound/H2O2 system with nano-ZnO was more effective for amoxicillin degradation than they were independently. The ultrasound/H2O2 system with nano-ZnO could be described by the Langmuir-Hinshelwood kinetic model. The addition of H2O2 and nano-ZnO to the ultrasound reactor enhanced the degradation of amoxicillin from 46.87% up to 98.9%. The recyclability and stability of nano-ZnO also showed that the catalytic activity of nano-ZnO during ultrasound degradation of amoxicillin was not lost up to five cycles. Thus, the application of ultrasound in the presence of H2O2 and nano-ZnO is favorable and effective for the remediation of aquaculture effluent.

Experimental investigations on red ochre for application in welding consumable development

This paper investigates the thermophysical, physicochemical, and surface properties of mineral waste red ochre, assessing suitability for application in welding consumable development. Red ochre is an anhydrous iron oxide derived from tailings of iron ore haematite. High iron and silica concentration makes it suitable for various engineering applications. Iron in the electrode coatings is known to increase arc stability, bead smoothness, and also it enhances slag detachability along with smoothening bead profile. The red ochre has been characterized for the properties of weight loss, density, specific heat, enthalpy, thermal conductivity, and diffusivity. Structural analysis of red ochre powder has been done using Fourier transformed infrared spectroscopy and X-ray diffraction. BET (Brunauer, Emmett, and Teller) surface area analysis has been done to estimate the surface properties, which include pore radius and specific surface area. The shielded metal arc welding electrodes have been developed by adding red ochre in a fixed proportion, and produced welds have been examined for visual defects, microstructure, and microhardness.

Removal of anionic and cationic dyes from wastewater by adsorption using multiwall carbon nanotubes

This paper evaluated the efficiency and reusability of multiwall carbon nanotubes (MWNTs) on removal of cationic and anionic dyes under effect of pH, dose of MWNTs and concentration of dyes. The characterization of MWNTs is characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), Raman spectra and BET (Brunauer, Emmett and Teller) surface area. SEM and TEM analyses showed that MWNTs had size within nano scale range of 10–50 nm. The experimental results indicated that the efficiency of removal of MWNTs increase under condition of normal pH, at contact time 60 min with agitation speed 240 rpm and initial concentration of dyes 10 mg/l. Under these optimal conditions, the removal reached 98.7% and 97.2% for anionic dyes and cationic dyes, respectively. For economic use, MWNTs can be used more than one time where the same experiments with the already used MWNTs was repeated and it was found that the percent removal is almost the same.

Incorporation of UiO-66 into Graphene Foam for Hydrogen Storage Applications

The fabrication of application-specific metal-organic framework (MOF) composites has the potential to shift more towards hydrogen storage system integration. The in-situ growth of nano particles on a graphene surface is a common technique for synthesizing graphene-inorganic nanocomposites and in this study, a graphene foam (GF) / zirconium-based MOF (UiO-66) composite was prepared using a two-step solvothermal method. Brunauer, Emmett and Teller (BET) surface area as well as hydrogen uptake capacity were measured under cryogenic conditions and compared to the values for pristine UiO-66. The GF/UiO-66 composite had a BET surface area of 1073 m2.g-1 and a hydrogen uptake capacity of 1.1 wt% at 77 K and 1.2 bar pressure, compared to 1367 m2.g-1 and 1.5 wt%, respectively for pristine UiO-66 under the same conditions. Besides the values being compromised relative to pristine UiO-66, the two-step in-situ synthesis approach yielded a composite with enhanced BET surface area and H2 uptake relative to a composite obtained from a single step synthesis approach. The composites further exhibited better thermal stability than the pristine UiO-66 and show promise for the development of powdered MOF materials towards hydrogen storage system integration.

Use of Wheat Straw Combustion Residues for Removal of Chlorinated Herbicide (2,4-Dichlorophenoxyacetic Acid)

The work highlights preparation of adsorbents using a common agricultural waste, wheat straw (WS) its characterization and adsorption efficacy. After separation of wheat seeds, whole stem and leaves remain as a waste. WS is used for the preparation of two adsorbents by distinct methods [ash by combustion wheat straw ash (WSA), biochar by pyrolysis i.e. wheat straw char (WSC)]. The synthesized adsorbents (WSA and WSC) are characterized by scanning electron microscopy, X-ray fluorescence, CHNS (ultimate analysis), Brunauer, Emmett and Teller (BET) surface area technique and Fourier transform infrared technique. XRF analysis confirmed presence of SiO2 (58%), K2O (6.85%), CaO (4.16%) and P2O5 (1.65%) in WPA all of which act as micronutrients to plants, whereas CPC contains carbon along with SiO2 (15%) as major constituent. A progressive increase in BET surface area was noted by change in preparation methods: WSA (37 m2/g) and WSC (96 m2/g). In this manuscript, adsorbents prepared using WS were characterized in detail and their adsorptive abilities were investigated using a commonly used herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), as a representative. Batch experiments were conducted to study the effect of different operational parameters such as adsorbent dose, initial 2,4-D concentration, contact time and pH. Experimental data were analyzed with Freundlich, Langmuir, and Temkin isotherm models, among which the Langmuir isotherm model showed the best fit. Pseudo-first-order kinetics and pseudo-second-order kinetics were applied to experimental data and pseudo-second-order kinetics showed the best fit. The adsorption capacity of WSA and WSC was found to be 1.89 and 3.02 mg/g, respectively, whereas equilibrium time was found to be 120, and 240 min, respectively. On the basis of adsorption capacity per hectare dose of WSA is recommended for removal of 2,4-D.

Treatment of Refinery Waste Water Using Environmental Friendly Adsorbent

This research evaluates the effectiveness of activated carbon prepared from walnut shell in the removal of pollutants from refinery waste water by adsorption technique. A series of batch experiments were carried out by varying the effluent solution pH, stirring time, stirring speed and adsorbent dosage in the reduction of pollutants from refinery effluent. Characterization of the adsorbent was performed using Scanning Electron Microscopy (SEM), Brunauer Emmett and Teller (BET) isotherm and Fourier Transform Infrared (FTIR) Spectroscopy. The best quality activated carbon was obtained with a particle size of 0.75 µm, activation temperature of 800 °C and activation time 24 h. The maximum BET surface area obtained was 165.2653 m2/g. The experimental results demonstrates that the highest percentage reduction in COD was 79%, using 0.6 g walnut shell powder at an optimum stirring speed of 100 rpm, at pH 6 and 120 min of contact time. The outcome of the result shows that walnut shell carbon is a potentially useful adsorbent for the removal of pollutants from refinery waste water.

Preparation and TG/DTG, FT-IR, SEM, BET Surface Area, Iodine Number and Methylene Blue Number Analysis of Activated Carbon from Pistachio Shells by Chemical Activation

AbstractIn this study, low cost activated carbon was prepared from the pistachio shell by chemical activation with zinc chloride (ZnCl2). The prepared activated carbon was characterized by thermogravimetry (TG) and differential thermal gravimetry (DTG), infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and Brunauer, Emmett and Teller (BET) surface area analyses. Results showed that the activation temperature and impregnation ratio have significant effect on the iodine number of the prepared activated carbon. The optimum conditions for preparing the activated carbon having the highest surface area were found to be an activation temperature of 700 °C, soaking time of 24 h and ZnCl2/ pistachio shell ratio of 50 %. The results showed that the BET surface area, total pore volume, iodine number and methylene blue (MB) number of activated carbon prepared under the optimum conditions were 1108 m2/g, 0.39 cm3/g, 1051 mg/g, 98.48 mg/g, respectively.

Adsorption of Cu(II) Ions in Aqueous Solutions by HCl Activated Carbon of Oil Palm

Activated carbon was prepared from oil palm empty fruit bunch (OPEFB) by pyrolysis at 873.15 K in a furnace and chemical activation using 0.01 M HCl. Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy and BET (Brunauer, Emmett and Teller) surface area analyses were taken into account to investigate the chemical functional group, to characterise the surface morphology and to determine total surface area the OPEFB AC, respectively. Experiments in batch mode were conducted to investigate Cu(II) adsorption capacity by the OPEFB AC whereas the system consisted of 1 g the OPEFB AC in 100 mL Cu(II) aqueous solution with initial concentration in the range of 10-70 mg/L, magnetic stirring at 75 rpm, room temperature of 300.15 K (± 2 K), at 1 atm and neutral pH over contact time in the range of 0-150 min. As the result, Cu(II) adsorption capacity increased exponentially over contact time and initial concentration. The Cu(II) adsorption kinetics followed the pseudo second order kinetics with the correlation coefficients (R2), kinetics rate constant and equilibrium adsorption capacity being 0.98, 4.81 mg/g and 0.15/min, respectively for initial Cu(II) concentration being 58.71 mg/L. In addition, Cu(II) adsorption isotherm followed the Langmuir equation with the R2 value, the mono-layer and over-all adsorption capacity being 0.99, 5.92 mg/g and 0.17 L/mg, respectively.

Effect of Modified MIL-53 with Multi-Wall Carbon Nanotubes and Nanofibers on CO<sub>2</sub> Adsorption

There is a growing need of counter assessing the increase of releases greenhouse gases such as carbon dioxide by researching an alternative technology that can help to reduce carbon dioxide content in atmosphere. This research work investigates the potential of MIL-53 as CO2 capture and storage candidate by conducting an experiment with different pressure between the synthesised and modified MIL-53. To investigate the effect of the Multi-wall carbon nanotubes (MWCNTs) and carbon nanofibers (CNFs) in MIL-53 towards CO2 adsorption performance. The synthesised samples were characterized by Fourier Transform Spectroscopy (FTIR) and Brunauer, Emmett and Teller (BET) techniques. A significant change is observed in the region of the aromatic deformation vibrations due to the different substitution patterns of the aromatic ring. BET surface area for MWCNT@MIL-53 is higher than CNF@MIL-53 and MIL-53. MWCNTs showed the adsorption of CO2 uptake is 0.3mmole-1/g at 100Kpa.

Studies on the Sorption of Benzene over DX 09 Carbon

BET (Brunauer Emmett and Teller) surface area and pores distribution for the samples DX 09 Carbon were measured for of DX 09 carbon by N2 adsorption (195 °C) with Autosorb-1C (American Quantachrome Company).The adsorption of benzene over DX 09 Carbon was measured in the static vacuum adsorption equipment, which was self-constructed in laboratory. It was experimentally found that the BET surface area is about 1008 m2/g, and the structure coefficients for DX-09 carbon were W=0.365 and B=1.32*10-6 measured by benzene adsorption and calculated by D-R equation.

A comparison of methods used to characterize the soil specific surface area of clays

In the present study the dry end of the soil water characteristic curve (SWCC) was used to estimate the specific surface area (SSA) of 90 engineering soil samples, using the Tuller and Or (2005) model. The results of SSA obtained by measurements using a WP4-T dew point potentiometer were compared with those obtained by means of traditional BET (Brunauer, Emmett, and Teller) surface area and the methylene blue (MB) techniques. An analysis of the results discussed in terms of the representative literature data showed that the SWCC method could provide a reliable estimation of the specific surface area in the case of fine grained inorganic soils with a total specific surface area greater than 5m2/g. A Hamaker constant with a value of 6×10−20J was found to be a good approximation, in the case of SSA calculations. The study also shows that karstic clay — terra rossa exhibits specific behavior which was not investigated in detail in the study, but clearly shows that further research is needed in order to modify the Tuller and Or (2005) model to a wider range of engineering soils with more complex mineralogical composition and texture.

Investigation of ultrasonic effect on synthesis of nano zero valent iron particles and comparison with conventional method

ABSTRACTIn this work, a new method of the synthesis of nano zero valent iron (nZVI) is presented. Ultrasonic wave as a novel method is used to synthesize nanoparticles and the physico‐chemical properties of particles compared with conventional synthesis method. Among the various synthesis methods, chemical reduction is widely used because of its simplicity. The effect of ultrasonic power (500 W, 1000 W), FeSO4.7H2O concentration (0.02, 0.05 and 0.08 M), NaBH4 concentrations (0.1, 0.25 and 0.4 M) and delivery rate of reducing agent on nZVI characteristics were investigated. Particle size distribution, morphology and surface composition were characterized by transmission electron microscopy, field emission scanning electron microscopy, X‐ray diffraction (XRD), Brunauer, Emmett and Teller (BET) surface area and particle size analyzer. It was found that the morphology of nanoparticles changed from spherical type to plate and needle type under high ultrasonic power. The size of 50% of nanoparticles was decreased from 90.3 to 29.9 nm under high precursor/reductant concentration and high ultrasonic power. Also, BET surface area was increased from 10 to 42 m2/g while using ultrasonic waves. The XRD patterns showed that the crystallinity of the nZVI prepared using ultrasonic conditions was poor because of the inadequate time for nuclei growth and crystallization. Therefore, the ultrasonic power could impose dramatic effect on the characteristics of the nanoparticles. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.