Low-cost Sorbent Research Articles

Characterization of natural Yemeni zeolites as powder sorbents for ammonium valorization from domestic waste water streams using high rate activated sludge processes

AbstractBACKGROUNDIn this study three natural Yemeni zeolites (NZ1, NZ2 and NZ3) having major minerals such as clinoptilolite and mordenite, were evaluated as low cost sorbents for the removal and recovery of ammonium ions.RESULTSThe zeolite samples, with pHPZC = 9.1 ± 0.2, 7.9 ± 0.2 and 7.4 ± 0.2 for NZ1, NZ2 and NZ3, respectively, showed high ammonium sorption capacities. At pH 8, for treated waste waters: (i) with low NH4+ levels (from 25 to 100 mgNH4/L); and (ii) for concentrated NH4+ side streams generated from the anaerobic digestion of sewage sludge (from 400 up to 1500 mg L‐1), maximum loading capacities of 27 to 51 mgNH4 g‐1 were measured for the studied zeolites. Measured sorption isotherms, in the concentration range 0.05 to 5 g L‐1, were well described by the Langmuir isotherm. The ammonium sorption kinetics was controlled by particle diffusion and was well described by both the homogeneous diffusion (HPDM) and shell progressive (SPM) models.CONCLUSIONComparison of the equilibrium data with results for natural and synthetic zeolites demonstrate the higher performance of the studied zeolites providing low residual ammonium values <1 mgNH4 g‐1 and <10 mgNH4 g‐1 when treating both diluted and concentrated‐NH4+ streams, respectively. © 2017 Society of Chemical Industry

Algae-based sorbents for removal of gallium from semiconductor manufacturing wastewater

Removal of various soluble metallic impurities from wastewater in semiconductor fabrication plants is a critical issue facing the microelectronics industry. Considering the large volume of wastewater and a highly variable concentration of these contaminants, finding a robust adsorption process using a low-cost sorbent is of great value and interest to this industry. Of particular interest is the development of a flow-through abatement method for treating the process-tool effluent before it is mixed with other wastewaters. In this work, a strain of freshwater green algae (Chlorella sorokiniana), representing an algae-based sorbent, and a simulated wastewater, containing soluble gallium as the metallic impurity, are used as model compounds. The choice of gallium is based on its increased use, and the lack of related adsorption data compared to the information available for other metals such as copper and arsenic. Both batch and continuous-flow operations were used in this study. Comprehensive process models were developed and validated for both batch and flow systems. These models were found to be valuable for understanding the process steps as well as for obtaining the fundamental parameters that are needed for process design and scale-up. The sorbent was found to have high adsorption capacity even at low pH values (14.1 mg/g at pH of 2.3, and 38.5 mg/g at pH of 2.8). Based on the comparison of adsorption rate and capacity with data on previously studied and conventional sorbents, such as activated carbon and ion-exchange resins, the use of this algae-based sorbent is potentially an attractive option for the removal of gallium from the process-tool wastewater.

Removal of methylene blue from aqueous solutions using alum Sludge: Sorption optimization by response surface methodology

A sorption process on low cost sorbents is one the promising methods for removing of these pollutants from aqueous solutions. This report describes use of drinking water treatment sludge which is abundantly available from drinking water treatment plants, to remove methylene blue (MB) dye from aqueous solutions. The main objective of this work is to determine the optimum conditions for removal of MB dye, a common compound that is used as a model for organic chemicals. Response surface methodology (RSM) is used in the optimization of the sorption process. Six independent important factors which are temperature of treatment, pH of solution, dosage of sorbent, initial dye concentration, contact period and temperature of sorption were investigated using batch sorption technique with a 26 half factorial faced centered central composite design

Green synthesis, characterization of biomaterial-supported zero-valent iron nanoparticles for contaminated water treatment

BackgroundIn this present work, we synthesized zero-valent iron nanoparticles (ZVIN) using reproducible Calotropis gigantea (CG) flower extract served as both reducing and stabilizing agent by completely green approach. ZVIN are widely used in contaminated water treatment and can be prepared by several different methods.MethodIron nanoparticles formed in this method are mainly ZVIN and were characterized by the various physicochemical techniques, viz, ultraviolet-visible absorption spectroscopy (UV-vis), Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX).ResultsFT-IR and UV-vis absorption spectra reveal that the polyphenols present in the CG flower extract may be responsible for the reduction and stabilization of the ZVIN. SEM images show some agglomeration among the particles and the average size of the particles in the range of 50–90 nm. ZVIN tend to agglomerate, resulting in a significant loss of reactivity. To overcome this problem, we have synthesized ZVIN that are immobilized on biomaterial with the help of chitosan. This low-cost sorbent was used to remove organic pollutants from waste water.ConclusionsHerein, we report the percentage of removal of methylene blue (MB) and aniline by synthesized sorbent from contaminated water. The adsorption isotherms of Langmuir and Freundlich models have been used to explain experimental equilibrium adsorption data. The adsorption of MB and aniline on sorbent follows pseudo-second order kinetics.

Preparation of amidoxime-functionalized mesoporous silica nanospheres (ami-MSN) from coal fly ash for the removal of U(VI)

It is usually difficult to control the microstructure of mesoporous silica materials using coal fly ash as raw materials. In this study, amidoxime-functionalized mesoporous silica nanospheres (ami-MSN) were prepared from coal fly ash using a novel interfacial cohydrolysis-condensation method in an alkane-aqueous system. Characterizations suggested a regular microstructure, high specific surface area (676 m2/g) as well as stable and uniformly distributed amidoxime groups in the ami-MSN framework. Furthermore, ami-MSN displays a high U(VI) removal capacity in sorption experiments (98.9% removal efficiency of 50 ppm U(VI) at a dosage of 600 mg/L). The sorption showed significant pH dependence. Introducing various cations and anions showed differing effects on sorption, which can be attributed to differing complexation abilities of ions/ami-MSN/U(VI). The sorption mechanism was also studied. In pursuit of the strategy of “treating wastewater with materials derived from waste,” this work suggests that ami-MSN can be an effective and low-cost sorbent for U(VI) removal.

Removal of hexavalent chromium in aqueous solutions using biochar: Chemical and spectroscopic investigations

Biochar is an emerging low-cost sorbent used for removing trace metals from water. In this study, we evaluated the removal potential of aqueous hexavalent chromium (Cr(VI)) by biochars produced from soybean (Glycinemax L.) and burcucumber (Sicyos angulatus L.) residues. The highest Cr(VI) removal from solution occurred at low pH values (pH2–5), and adsorption decreased approximately tenfold when the pH increased from 2 to 10. Synchrotron-based X-ray absorption spectroscopy (XAS) investigations showed that Cr(VI) species were reduced to trivalent chromium (Cr(III)) at the biochar surface following Cr(VI) adsorption. Linear combination fitting (LCF) of X-ray absorption near edge structure (XANES) data indicated that approximately 90% of the total Cr(VI) (962μM) was reduced to Cr(III). Extended X-ray absorption fine structure (EXAFS) fitting results yielded interatomic chromium (CrCr) distances consistent with the formation of Cr(III) precipitates as Cr(OH)3. Trivalent chromium is far less soluble than Cr(VI) and typically precipitates as amorphous Cr(III) solids. Thus, biochars produced by soybean and burcucumber residues are a promising technique for both adsorbing and reductively immobilizing Cr(VI) from aqueous solutions.

Use of metallurgical dust for removal chromium ions from aqueous solutions

The aim of the study was to determine the potential for the application of dust from steel plant as an effective sorbent for removing Cr(III) and Cr(VI) in the form of simple and complex ions – Acid Blue 193 dye from aqueous solutions. Three isotherms models were used to interpret the experimental results namely: Langmuir, Freundlich, and Dubinin–Radushkevich. Estimated equations parameters allowed to determine the binding mechanism. Based on laboratory studies it was found that the dust was characterized by high sorption capacities for Cr ions and dye from the aqueous solution. The sorption capacity of the dust for Cr(III) and Cr(VI) ions depended on the degree of oxidation, pH of solution and kind of anion and changed in series: Cr(III)-Cl pH=5.0> Cr(III)-SO4 pH=5.0> Cr(III)-Cl pH=3.0> Cr(III)-SO4 pH=3.0> Cr(VI) pH=5.0> Cr(VI) pH=3.0. Dust was also characterized by a high maximum sorption capacity of dye at a range of 38.2 – 91.7 mg/g, depending on the dose of dust. Based on the study it was found that dust from a steel plant, containing iron oxides, can be used as low-cost and effective sorbent to remove pollutions containing chromium ions, especially from acidic wastewater.

Fixed Bed Column Study for Removal of Textile Effluent Acid Orange 7 by NaOH Treated Eggshells and Amberlite FPA-98 as Efficient Adsorbents Using Response Surface Methodology.

In this study, we investigated the adsorption of Methylene blue (MB) dye on prepared activated carbons from eggshells treated with NaOH (TES) and eggshells Without Treatment (NTES) as a new and potential biosorbent. Biosorption capacities and rates of different kinds of treated bioadsorbent for Removal of MB dye from aqueous solutions were compared under laboratory conditions as a function of initial dye concentration, temperature and pH . The extent of dye removal increased with increasing in the initial concentration of the dye ,increased with increase in contact time and the initial pH of the solution and also decreased with increasing in temperature of the adsorbent. Adsorption data were modeled using the Freundlich and Langmuir to fit experimental equilibrium data at different solution temperatures and the isotherm parameters were calculated in order to describe the biosorption process; Langmuir model was found suitable for describing the biosorption of the dye by all the bioadsorbent. Among the two adsorbents , TES exhibited the highest dye uptake capacity (Q 0 =200 mg/g) at 20°C. A Comparison of different kinetic models parameters was evaluated for the pseudo-first-order and the pseudo-second-order model on the removal of MB. The results indicated that the dye uptake process followed the pseudo-second-order kinetics for each dye–adsorbent system. The thermodynamic parameters were evaluated; The negative values of ΔH° and ΔG° indicated respectively that the adsorption of MB onto TES and NTES was exothermic and spontaneous process, concerning ΔS° which is also negative, it have showed that disorder in the interface system decreases during the adsorption process. In summary, the results have established good potentiality for the TES and NTES particles to be employed as a low cost sorbent for the removal of colour and dyes from wastewater.

Adsorption of phosphorus by calcium-flour biochar: Isotherm, kinetic and transformation studies

Discharging phosphorus (P)-contaminated water directly into the aquatic environment leads to resource loss and eutrophication. Thus, removing P from waste streams is imperative. In this study, calcium-decorated biochar (Ca-BC) in different mass ratios of Ca to BC was designed to effectively adsorb P from solution. Ca-BC was characterized through X-ray diffraction (XRD) analysis, followed by isotherm and kinetic adsorption experiments. The decorated Ca on the BC surface was found to have preferred P adsorption ability. A design of calcium hydroxide (Ca(OH)2) to flour in a mass ratio of 2:1 was found to have a maximum adsorption capacity of 314.22 mg g−1 for P. The Langmuir and pseudo-second-order models fit the sorption process adequately. XRD analysis indicated that the preferable adsorption ability to P was due to the reaction of Ca(OH)2 and PO43−, forming the hydroxylapatite (Ca5(PO4)3(OH)) crystal. The P in solution was transformed to the crystal. Thus, Ca-BC is an environmental friendly and low-cost sorbent for P removal.

High-pressure CO2-CH4 selective adsorption on covalent organic polymer

Most of the newly discovered gas reservoir has high CO2 content (up to 70%), thus pose critical challenges to gas separation process due to the limitation of current acceptable technology. Recent report on COP-1 showed its potential as sorbent for CO2 capture due to its high adsorption capacity, low cost sorbent with good water resistance. However, scarce data on the potential of COP-1 and its selectivity for CO2/CH4 adsorbent for high pressure operation were reported. In this study, the adsorption isotherms were gravimetrically measured using magnetic suspension balance (MSB) within the range of 50–100 bar, at isothermal temperatures of 298, 318, 328 and 338 K. Langmuir and Sips isotherm models were correlated to the adsorption equilibrium data at critical and supercritical conditions. The ideal adsorption selectivities for CO2/CH4 separation were also predicted using Ideal Adsorbed Solution Theory (IAST). The ideal selectivity obtained (∼22) shows good separation performance for CO2 from CH4 onto COP-1. Furthermore, isosteric heats of adsorption calculated from Clausius-Clapeyron equation reveals that physisorption is the dominant factor for the interaction between adsorbates and surface of COP-1. Results also showed that the isostearic heat of COP-1 is a strong function of temperature and adsorbed amount. Nevertheless, the adsorption behaviour of COP-1 found in this work gives a good indication on the utilization of COP in CO2/CH4 separation for unexploited natural gas reservoir with high CO2 content.

Novel synthesis of cyano-functionalized mesoporous silica nanospheres (MSN) from coal fly ash for removal of toxic metals from wastewater

Trace amounts of toxic metals are usually difficult to be purified by conventional chemical precipitation or physical adsorption in wastewater. In this study, in order to realize high-value utilization of coal fly ash for wastewater purification, a novel method was applied to prepare high-performance mesoporous silica materials from coal fly ash. In comparison with a commonly used method, characterizations revealed that the new method obtained mesoporous silica nanospheres with uniformly distributed cyano groups (denoted by MSN), while the common method only obtained irregular sponge-like microstructure (denoted by ISM). Besides, MSN showed better hydrothermal stability, higher specific surface area (693m2/g) and more ordered mesopores from the comparison. Moreover, the sorption experiments of simulated wastewater suggested that MSN was better in removing toxic metals (Ni2+ and Cd2+) than ISM. For the practical wastewater from a battery plant, 2g/L dosage of MSN showed excellent performance for purification of trace amounts of various toxic metals (Ni, Cd, Mn, Zn, Hg and Pb), the concentration of which reduced to ppb level after MSN treated. The results suggested that MSN can be an effective and low-cost sorbent for removing various toxic metals from wastewater.

Production of sorbent from paper industry solid waste for oil spill cleanup

The aim of the study is to select a cellulosic waste material from paper industry solid wastes and process it for sorbent production. Four different solid wastes were collected from a local paper production facility and rejects were selected due to its sorption capacity and processability. Oil sorption experiments were conducted according to the ASTM F 726-12 method. Effect of sorbent dosage, contact and dripping time, recovery of the oil, reusability of the sorbent and sorption from the water surface were also determined. Maximum oil sorption capacity was determined as 9.67, 12.92 and 12.84g/g for diesel oil, 0W30 and 10W30 motor oils respectively for the static test and 8.27, 10.45 and 11.69g/g for the dynamic test. An efficient and low-cost sorbent was produced from paper industry rejects that can be used on land and on water.

Preliminary study on zinc ion removal from synthetic aqueous solutions using hard almond peel as a low-cost sorbent material

In the present work, a preliminary study on the potential of hard almond peels for the removal of zinc ions from aqueous synthetic solutions has been investigated. Kinetic data and equilibrium sorption isotherm were measured in batch conditions. For an initial metal concentration of 100 mg/L tested here, the quantity of zinc sorbed was contact time dependent: it increased with an increase of this parameter. The necessary time to reach the sorption equilibrium was about 6 h and an increase of removal time to 24 h did not show notable effects. At equilibrium, about 24 % of initial zinc solution was removed by hard almond peels (q e = 23.86 mg/g) under these experimental conditions. Two simplified kinetic models including a first-order rate equation and a pseudo second-order rate equation were selected to describe the metal sorption kinetics. The process followed a pseudo second – order rate kinetics. Langmuir and Freundlich models were used to describe sorption equilibrium data at natural pH of solution. Results indicated that the Langmuir model gave a better fit to the experimental data than the Freundlich model. Maximum zinc uptake obtained was q m = 56 mg/g under the investigated experimental conditions.

BOF steel slag as a low-cost sorbent for vanadium (V) removal from soil washing effluent

Soil washing is an effective remediation method to remove heavy metals from contaminated soil. However, it produces wastewater that contains large amounts of heavy metals, which lead to serious pollution. This study investigated the removal of vanadium (V) from synthetic soil washing effluent using BOF steel slag. The effects of particle size, slag dosage, initial pH, and initial vanadium concentration on removal behavior were studied. Adsorption kinetics and isotherms were also analyzed. The results showed that the vanadium removal efficiency increased as the steel slag particle size decreased and as the amount of slag increased. The initial pH and vanadium concentration did not play key roles. At the optimum particle size (<0.15 mm) and dosage (50 g/L), the removal rate reached 97.1% when treating 100 mg/L of vanadium. The influence of the washing reagent residue was studied to simulate real conditions. Citric acid, tartaric acid, and Na2EDTA all decreased the removal rate. While oxalic acid did not have negative effects on vanadium removal at concentrations of 0.05–0.2 mol/L, which was proved by experiments using real washing effluents. Considering both soil washing effect and effluent treatment, oxalic acid of 0.2 mol/L is recommended as soil washing reagent.

Elemental mercury reaction chemistry on brominated petroleum cokes

Activated carbon injection is a proven technology to capture mercury from flue gases. Due to the high cost and environmental concerns related to its disposal, high efficiency and low-cost sorbents have been studied to replace activated carbon. In this study, the petroleum coke obtained from two Canadian petroleum refineries, with high inherent sulfur content and impregnated with bromine, was compared to investigate elemental mercury capture mechanisms. These carbon-based sorbents showed excellent mercury removal efficiency at 100 and 200 °C. Elemental analysis, Brunauer–Emmett–Teller surface area, pore volume and thermogravimetric analysis were used to characterize the sorbents. X-ray photoelectron spectroscopy was used to examine the significant changes in chemistry and oxidation states of Br, S and Hg on the sorbent surface. More active mercury binding sites were created on brominated petroleum cokes after the chemical-mechanical bromination process. The inherent thiophene and organic sulfide in petroleum coke played a dominant role in mercury capture.

Statistical methodology for biosorption of nitrate (NO3 −) ions from aqueous solution by Pleurotus eryngii fungal biomass

In the present study, Central Composite Design (CCD) of Response Surface Methodology was employed to investigate the effects of different operating conditions on the removal of nitrate (NO3 −) ions from aqueous solution onto Pleurotus eryngii dried fungal biosorbent. A three level, three factors CCD was used to evaluate the effects and interactions of the process variables, i.e., solution pH, biosorbent dose and initial NO3 − concentration. The second order mathematical model was developed by regression analysis of the experimental data of 17 batch runs. Analysis of Variance, F test, Student’s t test and lack of fit test showed that NO3 − ions biosorption were slightly concentration dependent, but markedly increases with solution pH and biosorbent dose. The optimum pH (7.47), biosorbent dose (0.29 g) and initial concentration (772.02 mg L−1) were found by desirability function. Under these optimum combinations of process parameter conditions, maximum removal of 88.38% was obtained that assisting its use in larger scale. P. eryngii has been characterized by using different physicochemical methods. The characterization suggested a possible contribution of carboxyl and hydroxyl groups in the process of biosorption. Hence, it is suggested that P. eryngii has potential for biosorption as a low-cost and effective sorbent for NO3 − removal from aqueous solution.

Synthesis of sulfur nanoparticles-loaded alumina as a low-cost sorbent for the preconcentration of nickel from real samples

ABSTRACTThis study reports a simple method for the synthesis of α-sulfur-nanoparticles-loaded alumina as a reliable kind of sorbents in solid-phase extraction (SPE) methods for the preconcentration and determination of trace levels of Ni(II) from real samples. The most important advantage of this technique is not using the ligand as a complexing agent and hence the disadvantages of other SPE methods have been avoided. The calibration graph was linear over the range of 0.66–100 µg/L and the relative standard deviation (RSD) of 1.98% at 50 µg/L was obtained. The limit of detection (LOD) and preconcentration factor (PF) were obtained as 0.22 µg/L and 250, respectively. The maximum adsorption capacity of the adsorbent was found to be 18 mg/g for Ni(II).

Removal of Some Heavy Metals from Aqueous Solution by Low-cost Sorbents

Removal of Some Heavy Metals from Aqueous Solution by Low-cost Sorbents

Removal of Heavy Metals and Pharmaceuticals From Contaminated Water Using Waste Sludge – Kinetics and Mechanisms

The aim of this study was to investigate the adsorption of heavy metals (CrTOT, Ni2+, Cu2+, and Zn2+) in wastewater originated from galvanization process and pharmaceuticals (ciprofloxacin and dexamethasone) in aqueous solutions on waste sludge. To get the insight in the adsorption process, the adsorption kinetics and mechanisms are described. The physico‐chemical properties of the waste sludge were determined by scanning electron microscopy coupled with energy dispersive spectroscopy, X‐ray diffraction technique, energy dispersion X‐ray spectrometry, surface area and gas adsorption porosimetry, and laser diffraction. The adsorption on waste sludge was performed as batch tests and the concentration of heavy metals and pharmaceuticals was monitored by atomic absorption spectrometry and UV/Vis spectrophotometry, respectively. The rates of pharmaceuticals adsorption dependent on different initial concentration were explained. The kinetics of heavy metal ions and pharmaceuticals adsorption on the sludge was analyzed using four different models. The pseudo second‐order model assuming chemical adsorption as the rate limiting process showed the best agreement. Furthermore, the results revealed that the adsorption involves complex processes, including film diffusion and intraparticle diffusion. The investigated industrial waste sludge is a promising non‐hazardous and a low cost sorbent with relatively high surface area which can be used for removal of heavy metal ions (CrTOT, Ni2+, Cu2+, and Zn2+), and pharmaceuticals (ciprofloxacin and dexamethasone) from wastewater.

Adsorption of Copper and Zinc Ions from Aqueous Solutions Using Montmorillonite and Bauxite as Low-Cost Adsorbents

The objectives of this study were to investigate the adsorption of Cu-II and Zn-II on montmorillonite and bauxite and to discuss the usability of these adsorbents in environmental applications. The maximum adsorption was found for Cu (II) on bauxite with a Kf value of 4.179 L g−1; the maximum adsorbed capacity (Qo) calculated from the Langmuir model reached 9.115 mg g−1. Both raw materials have the potential to be effectively used to produce low-cost sorbents for copper and zinc removal from wastewater. They could be used as alternative adsorptive barriers and as amendments to soils at old mining areas, to prevent metal leaching into groundwater, or to isolate urban waste leachate.