Ni Adsorption Research Articles

Exploiting the performance of hyper-cross-linked polystyrene for removal of multi-component heavy metal ions from wastewaters

In this research, Hyper-cross-linked polystyrene was used for simultaneous removal of nickel and lead ions. The necessary number of experiments and optimum values of each factor were determined using response surface methodology (RSM). The optimum value of temperature, nickel, and lead concentrations, and pH was obtained 60 ℃, 50.715 mg/L, 80 mg/L, and 7 respectively, for Ni(II) adsorption in which the nickel uptake and selectivity were calculated 146.66 mg/g and 0.511, respectively. The optimum value of temperature, nickel, and lead concentrations, and pH was obtained 65 ℃, 80 mg/L, 40 mg/L, and 7 for Pb(II) adsorption in which the lead uptake and selectivity were calculated 137.272 mg/g and 3.951, respectively. The different isotherm models have been applied for both single and multi-component systems. It was concluded that both single and multi-component systems obeyed Freundlich isotherm model, which demonstrated the heterogeneous and multi-layer of the adsorbent. Besides, thermodynamic parameters such as ΔH°, ΔS°, and ΔG° expressed the exothermic and spontaneous nature of the adsorption of nickel and lead ions. Finally, the value of ΔH° for nickel and lead ions was lower than 40 kJ/mol, which implied the process was physical.

Efficient adsorption of Cu(II), Pb(II) and Ni(II) from waste water by PANI@APTS-magnetic attapulgite composites

In the article, Polyaniline (PANI) was introduced into the iron oxide/attapulgite (Fe3O4/ATP) system through aminopropyltriethoxysilane (APTS) for the first time, prepare a PANI@APTS-Fe3O4/ATP adsorption material, and use it for Cu(II), Pb(II) and Ni(II) adsorption. Firstly, Fe3O4/ATP was prepared by co-precipitation method, then aniline was assembled by APTS, and finally PANI@APTS-Fe3O4/ATP was generated by oxidative polymerization. Meanwhile, the dispersibility of the magnetic carrier enhances the dispersion of the ATP modified material in the aqueous phase, and improves the inclusion adsorption performance and the adsorption process. The maximum adsorption capacity of PANI@APTS-Fe3O4/ATP for Cu(II), Pb(II) and Ni(II) are 189.03, 270.27 and 142.86 mg g−1, respectively. The adsorbent is a homogeneous monolayer adsorption, which is in line with Langmuir model. Compared with other reported ATP modified materials, PANI@APTS-Fe3O4/ATP can quickly reach equilibrium, which only takes 15 min. Besides, it has magnetism and good stability, so it is very likely to be used in practice.

Chemically modified palm kernel shell biochar for the removal of heavy metals from aqueous solution

Heavy metals eradication from water is a complicated subject, therefore a viable, resilient, and green technology is imperative. Heavy metal removal can be accomplished through easy access, economical, and efficient sorbents derived from agricultural waste. In the current study, palm kernel shell (PKS) waste was converted into biochar (PKSC) via pyrolysis. Chemical modification was performed on PKSC via acid-base treatment to refine its adsorption properties. Batch experiments were conducted to study the efficiency of PKSC and acid-base treated PKSC (MPKSC) for removal of Cr(IV), Ni(II) and Cu(II). The surface area was increased from 112.934 m 2/g to 149.670 m 2/g by acid-based treatment. Batch adsorption study showed that the MPKSC afforded high removal efficiency for Cu (99.29%), Ni (96.77%) and Cr (42.97%). The Cr(IV) and Ni(II) adsorption by PKSC, as well as Cr(IV), Ni(II) and Cu(II) adsorption by MPKSC were best represented by Freundlich isotherm. However, Cu(II) adsorption by PKSC can explained by using Langmuir isotherm. All studied heavy metals fitted the pseudo-second-order kinetic.

Response Surface Modeling and Optimization of Ni(II) and Cu(II) Ions Competitive Adsorption Capacity by Sewage Sludge Activated Carbon

In this study, response surface methodology (RSM) was used to evaluate the experimental parameter’s effect in the competitive adsorption capacity of Ni(II) and Cu(II) ions using activated carbon prepared from sewage sludge. The metal removal efficiency was optimized toward various parameters using central composite design (CCD) under RSM. The model’s predictions are in good agreement with experimental results (R2 = 0.986, 0.974 and Adj-R2 = 0.960, 0.950 for Ni(II) and Cu(II) ions, respectively). ANOVA results showed that the process was mainly influenced by the Ni(II) concentration and adsorbent dose, whereas the other factors showed lower effects. The optimum Ni(II) concentration, Cu(II) concentration, adsorbent dose, contact time and temperature were found to be 40 mg/L, 40 mg/L, 4 g/L, 100 min and 30 °C. Under optimal conditions, maximum adsorption capacity of both metals (7.48 and 4.04 mg/g, respectively for Ni(II) and Cu(II) ions) was obtained.

Role of support in tuning the properties of single atom catalysts: Cu, Ag, Au, Ni, Pd, and Pt adsorption on SiO2/Ru, SiO2/Pt, and SiO2/Si ultrathin films.

The role of the support in tuning the properties of transition metal (TM) atoms is studied by means of density functional theory calculations. We have considered the adsorption of Cu, Ag, Au, Ni, Pd, and Pt atoms on crystalline silica bilayers, either free-standing or supported on Ru(0001) and Pt(111) metal surfaces. These systems have been compared with an hydroxylated SiO2/Si(100) film simulating the native oxide formed on a silicon wafer. The properties of the TM atoms change significantly on the various supports. While the unsupported silica bilayer weakly binds some of the TM atoms studied, the SiO2/Ru(0001) or SiO2/Pt(111) supports exhibit enhanced reactivity, sometimes resulting in a net electron transfer with the formation of charged species. Differences in the behavior of SiO2/Ru(0001) and SiO2/Pt(111) are rationalized in terms of different work functions and metal/oxide interfacial distances. No electron transfer is observed on the SiO2/Si(100) films. Here, the presence of hydroxyl groups on the surface provides relatively strong binding sites for the TM atoms that can be stabilized by the interaction with one or two OH groups. The final aspect that has been investigated is the porosity of the silica bilayer, at variance with the dense SiO2/Si(100) film. Depending on the atomic size, some TM atoms can penetrate spontaneously through the six-membered silica rings and become stabilized in the pores of the bilayer or at the SiO2/metal interface. This study shows how very different chemical properties can be obtained by depositing the same TM atom on different silica supports.

Adsorption of Ni2+ in aqueous solution by KMnO4 modified biomass: investigation on adsorption kinetics and modification mechanism

ABSTRACT In this study, KMnO4 modification was proved to effectively increase the Ni2+ adsorption capacity of biomass. In order to clarify the KMnO4 modification mechanism, the Ni2+ adsorption characteristics of KMnO4 modified corncob (PPCB) under adsorption time, pH and Ni2+ concentration were studied. The results showed that the adsorption was the pseudo second-order kinetic process, indicating that chemisorption was the dominated process, which followed the Langmuir isotherm model and the highest Ni2+ adsorption capacity of PPCB reached 35.6 mg/g. By KMnO4 modification, the corncob was oxidized to generate carboxylates, and the MnO2 (reduction product) was loaded on the modified corncob, both carboxylates and MnO2 increased the Ni2+ adsorption capacity of PPCB. The molecular dynamic results indicated the carboxylate structures had the strongest adsorption capacity. Moreover, the Ni2+ removal efficiency of KMnO4 modified biomass decreased linearly with the increase of lignin content in biomass, while KMnO4 modified lignin showed a good adsorption performance, indicating that the cross-linked structures between lignin and other components in the biomass could inhibit the adsorption capacity of PPCB.

Kinetics of Cd, Co and Ni Adsorption from Wastewater using Red and Black Tea Leaf Blend as a Bio-adsorbent

Every year there is deterioration in water quality. This is due to human activity. The current environmental strategies of many countries motivate the scientific community to develop reliable, economically viable and environmentally friendly technologies that are able to remove pollutants from the environment, including water. The study purpose is to determine of influence regularity of the bio-adsorbent composition and amount, which consists of red and black tea leaves mixture, on the Cd, Co and Ni adsorption process based on experimental data. As well as determine the most rational bio-adsorbent dose and the necessary red and black tea dose in bio-adsorbent to achieve MPC of heavy metals, with which process duration will be minimal. Initially, to study the adsorption process kinetics, the nature of the curve that describes the obtained experimental values was visually analyzed. To determine the adsorption process kinetic regularity, which most adequately and reliably describes the experimental data and to determine the values of the coefficients in the exponential regularity, the least squares method was used. It was observed that for Cd and Co, an increase in the black and red tea amount leads to a drastic reduction of the adsorption process time (up to 10 times); while for Ni the black tea addition slows down the adsorption process. Ni adsorption is the most complex and for certain bio-adsorbent composition values, complete Ni removal cannot be achieved in a technologically reasonable adsorption time. The technological process of Cd, Co and Ni adsorption can be expedient, if it is carried out in several stages with optimal red and black tea amounts for each of the metals. Adsorption process kinetic regularity, which was determined, can be used to calculate of adsorption process technological parameters in values wide range.

Conversion of crop, weed and tree biomass into biochar for heavy metal removal and wastewater treatment

It was quantified the influence of four different biomasses viz. tree, weed and crop on twenty compositional characteristics of produced biochar for their wide range of environmental application. The removal of most widespread heavy metal ions (cadmium (Cd), lead (Pb), nickel (Ni), zinc (Zn), copper (Cu) and arsenic (As)) by adsorption on four biochars has been investigated. Initial evaluation revealed that all the biochar was efficient in removing a mixture of six heavy metals from aqueous phase having maximum removal for arsenic and minimum nickel. Utilizing four different biochars, the average removal rate of heavy metal from aqueous solution was 49.5–66.1% (Cd), 47.3–60.0% (Pb), 45.5–60.6% (Ni), 46.6–60.8% (Zn), 49.3–63.2% (Cu) and 52.7–64.2% (As) compared with no biochar treatment. The percent decrease of Pb heavy metal adsorption with increase in maximum contaminant level (MCL) from 1- to 5-fold was 54.7 (black gram biochar), 53.5 (pine needle biochar), 52.02 (Lantana camara biochar) and 50.0 (maize stalk biochar). The effect of dose study showed that As adsorption on all the four types of biochar was most favourable and Ni adsorption was the most awful. At the bio-filtration stage, the wastewater was treated with four different biochars and the physico-chemical character changes were recorded before and after treatment with biochar. The wastewater total chemical oxygen demand, total soluble solid, ammonia, total potassium and nitrogen and total potassium values demonstrated an 88.3–90.6%, 84.8–81.1%, 90.9–86.6%, 58.8–69.3% and 88.1–77.96% decrease, respectively. Additionally, the wastewater As, Cd, Cr, Pb, Zn and Cu values resulted a 78.5–86.5%, 52.6–94.7%, 83.1–88.1%, 94.6–77.8%, 90.1–94.5% and 93.3–95.5% decrease, respectively, after being passed via biochar bio-filter. Therefore, the four developed biochar explored huge potential for removal of heavy metal along with wastewater treatment to meet guidelines for wastewater effluent disposal.

Heavy Metal Ion Adsorption Properties and Stability of Amine-sulfur Modified Biochar in Aqueous Solution

A novel biochar was prepared by modification with corn straw, ethylene triamine, and carbon disulfide, and its adsorption properties and stability with respect to heavy metal ions in single and mixed systems (Pb2+, Ni2+, and Cd2+) were investigated. Characterization analysis confirmed the successful modification of an amine-sulfur double group on the surface of the biochar, which had abundant functional groups with a large specific surface area. Adsorption experiments under the single system indicated that the adsorption equilibrium time was 4 h and the optimum dosages were 1, 0.8, and 1.2 g·L-1. The adsorption met the conditions of the quasi-second-order kinetic equation. Under the ternary system, the adsorption equilibrium time was reduced to 1.5 h, the optimum dosages were 0.4, 1.6, and 0.8 g·L-1, and the adsorption sequence was Pb2+ > Cd2+ > Ni2+. The total amount of adsorption was 0.67 mmol·g-1, which was higher than that of single heavy metal ions, indicating that amine-sulfur modified straw biochar (BC-SN) has an improved treatment effect on polluted water under the coexistence of three heavy metal ions. The Pb2+ and Cd2+ adsorbed by the biochar was stably bound in the form of heavy metal sulfide and a chelated amino group. In contrast, the adsorption of Ni2+ was via the mixed adsorption of various functional groups. When Pb2+ and Cd2+ compete for adsorption, the binding energy is higher and adsorption stability is more reliable.

Thermodynamic and kinetic studies of heavy metal adsorption by modified nano-zeolite

ABSTRACT In this study, for the first time, nano-sized clinoptilolite zeolite produced by a dry planetary ball mill in the presence of sodium hexametaphosphate was employed to remove heavy metals. Results represented that the concentration of adsorbed ions on nano-zeolite increases with increasing pH, initial concentration of metals, and temperature. The maximum adsorption efficiency for Ni2+, Cd2+, and Cu2+ was found to be 74.20%, 97.60%, and 99.50% at a pH of 7.5 and 60°C, respectively. The adsorption of Ni2+, Cd2+ and Cu2+ on nano-zeolite increased from 44.40% to 74.20 %, 76.4% to 97.60%, and 94.30% to 99.50% by enhancing temperature from 20 to 60 °C. Furthermore, Gibbs’s free energy obtained from thermodynamic evaluations depicted that adsorptions had spontaneous behavior. According to Langmuir models, the maximum capacity (qm) of Ni2+, Cu2+, and Cd2+using nano-zeolite was found to be 17.79, 17.92, and 18.32 mg/g. Adsorption isotherms showed that results fitted better on the Langmuir model for Ni2+and Cu2+ and the Freundlich model for Cd+2 because the correlation coefficients (R2) were 0.99 for them. Finally, the pseudo-second-order kinetic model was selected to interpret the experimental data.

Sequential separation of Cu(II)/Ni(II)/Fe(II) from strong-acidic pickling wastewater with a two-stage process based on a bi-pyridine chelating resin

A self-synthesized bi-pyridine chelating resin (PAPY) could separate Cu(II)/Ni(II)/Fe(II) sequentially from strong-acidic pickling wastewater by a two-stage pH-adjusted process, in which Cu(II), Ni(II), and Fe(II) were successively preferred by PAPY. In the first stage (pH 1.0), the separation factor of Cu(II) over Ni(II) reached 61.43 in Cu(II)-Ni(II)-Fe(II) systems. In the second stage (pH 2.0), the separation factor of Ni(II) over Fe(II) reached 92.82 in Ni(II)-Fe(II) systems. Emphasis was placed on the selective separation of Cu(II) and Ni(II) in the first-stage. The adsorption amounts of Cu(II) onto PAPY were 1.2 mmol/g in the first stage, while those of Ni(II) and Fe(II) were lower than 0.3 mmol/g. Cu(II) adsorption was hardly affected by Ni(II) with the presence of dense Fe(II), but Cu(II) inhibited Ni(II) adsorption strongly. Part of preloaded Ni(II) could be replaced by Cu(II) based on the replacement effect. Compared with the absence of Fe(II), dense Fe(II) could obviously enhance the separation of Cu(II)-Ni(II). More than 95.0% of Cu(II) could be removed in the former 240 BV (BV for bed volume of the adsorbent) in the fixed-bed adsorption column process with the flow rate of 2.5 BV/h. As proved by X-ray photoelectron spectrometry (XPS) and density functional theory (DFT) analyses, Cu(II) exerted a much stronger deprotonation and chelation ability toward PAPY than Ni(II) and Fe(II). Thus, the work shows a great potential in the separation and purification of heavy metal resources from strong-acidic pickling wastewaters.

Application of zeolite intercalated calcium carbonate from pokea shell (Batissa violacea celebensis) waste as adsorbent Ni2+ ion

The purpose of this study was to obtain adsorbent zeolite modified by CaCO3 from pokea shell (PS) waste to adsorb Ni2+ ions. Adsorbents are made through the intercalation method, where the PS powder is mixed to zeolites in 0.1 M HCl with 3 ratios of 3:1, 2:2 and 1:3 (g/g), respectively. The optimization of adsorption power was carried out by using parameters such as pH, contact time and concentration variation of Ni2+ ion solution. The analysis of the adsorption capacity and type of bond using the Freundlich and Langmuir isotherm equations. The characterization of the active site composition of the adsorbent was used FTIR instrument. FTIR spectra showed that CaCO3 modified zeolite adsorbent include Si-OH, O-H, Al-O, Si-O, C-H, Ca-C and C-O from CaCO3 and C-O from CO3 2-functional groups. The results showed that the best adsorbent was it with the zeolite-PS powder ratio of 3:1, the optimum conditions were obtained at pH 5, contact time at 60 minutes and 45 mg l−1 concentration. Adsorption of Ni2+ ions meets the Freundlich isothermal with adsorption capacity and energy of 1.33 mg g−1 and 5.78 kJ mol−1.

A novel activated carbon from human hair waste: Synthesis, characterization and utilization thereof as an efficient, reusable Ni (II) adsorbent

In this study, the novel hair based activated carbon (HAC) was synthesized from human scalp hair using calcium chloride as an activating agent and characterized using FTIR, Raman, CHNS, BET, SEM, and XRD analysis methods. The Ni (II) adsorption investigations were performed in batch mode experiments by determination of its initial and momentary concentrations in the solution. The effect of pH, adsorbent dose, Ni (II) initial concentration, and adsorption time on HAC adsorptivity, were evaluated using Taguchi experimental design method. Kinetics, isotherms, and regeneration studies were also performed. The optimum values of the four parameters, mentioned above, were found as 5, 1 ​g/L, 27.70 ​mg/L, and 60 ​min, respectively. The Ni (II) adsorption kinetic and isotherm were best described by pseudo-second order and BET models, respectively. After five adsorption-desorption cycles, a very small decrease (6.85%) in adsorbent capacity was observed. According to the BET isotherm model, the maximum multilayer adsorptivity was 63.44 ​mg/g. Due to the simple preparation, ease to scale-up, high adsorptivity, as well as regeneration results, the obtained bio-based activated carbon can be introduced as a strong, stable, and reusable adsorbent of Ni (II).

Adsorption of Ni2+ and Cu2+ Ions from Wastewater by a Silanized Zeolite Produced with a 3-Mercaptopropyl Trimethoxysilane Modification.

Adsorption characteristics of a silanized zeolite for Ni2+ and Cu2+ ions in water solutions were analyzed by SEM, FTIR and XRD techniques. For ion removal, an optimum ratio of 1 g/L silanized zeolite was obtained for adsorbing a Ni2+ and Cu2+ solution. Equilibrium states at 220 and 108 min were reached for the adsorption of Ni2+ and Cu2+, respectively. In a pH range of 2-6, the modified zeolite demonstrated an excellent resistance to acids by exhibiting a high adsorption capacity, which increased with a larger pH.

Nickel isotopes and rare earth elements systematics in marine hydrogenetic and hydrothermal ferromanganese deposits

Attention is now being given to Ni isotope systematics in hydrogenetic marine ferromanganese (Fe-Mn) crusts as paleoceanographic proxies. Previous work focused on identifying both mineralogy (post-depositional) and source effects (Gall et al. 2013; Gueguen et al. 2016), in particular regarding hydrothermal inputs in the oceans and the response of Ni isotope biogeochemical cycling through time. The most important sink for Ni in the oceans is the Fe-Mn oxides sink, but estimation of its Ni isotope composition is only based on hydrogenetic Fe-Mn crusts. In this study, we investigated a range of Fe-Mn deposits including Fe-Mn deposits variably affected by hydrothermal inputs, including hydrothermal deposits from the Lau back-arc basin (South West Pacific) and Lo'ihi seamount (Hawaii), hydrogenetic crust and nodules from the Bauer Basin (Pacific Ocean). Nickel isotope ratios were measured by multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) using a double-spike (61Ni and 62Ni) correction method. The combination of Ni isotopes and rare earth element (REE) geochemistry show that Ni isotope fractionation in Fe-Mn deposits is essentially controlled by formation processes of the deposits (such as the rate of formation, the initial Mn-phase and sorption processes) which are also related to the depositional environment. Consistent with previous studies, pure hydrogenetic crusts are characterized by isotopically heavy Ni isotope signatures (δ60/58Ni values range from ‰ 0.9 and 2.5‰) and well-developed positive Ce anomalies. In contrast, mixed hydrothermal‑hydrogenetic crust and nodules from the Bauer Basin (East Pacific) display negative Ce anomaly and lighter δ60/58Ni values (0.3‰ to 0.4‰), which are interpreted as the result of far-field hydrothermal inputs of Fe-Mn precipitates from the East Pacific Rise.Nickel in hydrothermal deposits from the Lau Basin (0.5 and 1.1‰) and Lo'ihi seamount (−0.8 to −1.5‰) is isotopically lighter than in hydrogenetic Fe-Mn crusts. Light δ60/58Ni values in Lo'ihi deposits is due to the removal of Ni during Ni adsorption from seawater and from the hydrothermal fluid (between 0 and 1.4‰) on Fe-oxides followed by isotope fractionation between the fluid and the mineral phase. Results suggest that Ni isotopes in hydrothermal Fe-rich deposits are strongly fractionated relative to the seawater/fluid source due to partial removal of Ni on Fe-phases. Hydrothermal Mn-oxides deposits from the Lau Basin acquired their Ni isotope signature through Ni adsorption and continuous exchange of Ni with seawater. We propose that the systematic difference in Ni isotope signatures between hydrogeneous and hydrothermal Fe-Mn deposits is related to the mechanisms of Ni uptake into oxide minerals (e.g., birnessite vs. todorokite; Fe-oxides vs. Mn-oxides) which depend on the rate of formation and the source of Mn and Fe to marine ferromanganese deposits (i.e., depositional environment) rather than Ni sources.

Modulation of electronic structure properties in bilayer phosphorene nanoribbons by transition metal atoms

To explore the novel properties and applications of two-dimensional black phosphorene, we perform a first-principles study on the modulation of the structure and electronic properties of bilayer phosphorene nanoribbons (BPNRs) by using transition metal (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) atoms. For one-dimensional zigzag-edge AA-stacked bilayer phosphorene nanoribbons with hydrogen passivation, we find that the atomic stacking of the BPNRs reorders from the AA to the AE stacking. The AE-stacked structure is the most stable structure for one-dimensional zigzag BPNRs. All the BPNRs with widths N = 4–10 exhibit semiconductor character with indirect band gaps (1.17, 1.01, 0.92, 0.84, 0.75, 0.74, and 0.72 eV), which gradually decrease with increasing nanoribbon width. The adsorption energies show that all the TM atom-adsorbed 4-BPNR compound systems [PTMP] can form stable structures, however, the most stable structures have different adsorption energies (−9.38, −10.73, −13.19, −8.26, −13.68, −9.73, −10.41, −10.33, and −5.98 eV) for different TM (Sc, Ti, V, Cr, Mn, Fe, Co, Ni and Cu) atoms. The calculated bond lengths, charge transfer, and difference charge density of [PMnP] systems indicate that there are strong chemical interactions between the TM atoms and their adjacent P atoms in the BPNRs, resulting in the formation of TM-P ionic bonds. The adsorption of TM atoms induces various electronic structures in 4-BPNR. The [PTMP]1 systems exhibit metallic properties with the adsorption of Sc, Co, and Cu atoms, and semiconductor properties with the adsorption of Ti, V, Cr, Mn, Fe, and Ni atoms with band gaps of 0.30, 0.18, 0.19, 0.20, 0.61, and 0.08 eV, respectively. The Ni and Cu adsorption systems show magnetic quenching with no magnetic moments in all the compound systems [PTMP]. The [PCrP]1 has the maximum magnetic moment of approximately 3.62 μB amongst all the [PTMP]1 systems, while the [PVP]1 and [PMnP]1 systems have magnetic moments of 1.66 μB and 1.84 μB, respectively. Our results show that TM atom-adsorbed bilayer phosphorene nanoribbons exhibit tunable electronic structures and magnetic properties for potential applications in nanoelectronics.

Kinetics of Cd, Co and Ni Adsorption from Wastewater using Red and Black Tea Leaf Blend as a Bio-adsorbent

Every year there is deterioration in water quality. This is due to human activity. The current environmental strategies of many countries motivate the scientific community to develop reliable, economically viable and environmentally friendly technologies that are able to remove pollutants from the environment, including water. The study purpose is to determine of influence regularity of the bio-adsorbent composition and amount, which consists of red and black tea leaves mixture, on the Cd, Co and Ni adsorption process based on experimental data. As well as determine the most rational bio-adsorbent dose and the necessary red and black tea dose in bio-adsorbent to achieve MPC of heavy metals, with which process duration will be minimal. Initially, to study the adsorption process kinetics, the nature of the curve that describes the obtained experimental values was visually analyzed. To determine the adsorption process kinetic regularity, which most adequately and reliably describes the experimental data and to determine the values of the coefficients in the exponential regularity, the least squares method was used. It was observed that for Cd and Co, an increase in the black and red tea amount leads to a drastic reduction of the adsorption process time (up to 10 times); while for Ni the black tea addition slows down the adsorption process. Ni adsorption is the most complex and for certain bio-adsorbent composition values, complete Ni removal cannot be achieved in a technologically reasonable adsorption time. The technological process of Cd, Co and Ni adsorption can be expedient, if it is carried out in several stages with optimal red and black tea amounts for each of the metals. Adsorption process kinetic regularity, which was determined, can be used to calculate of adsorption process technological parameters in values wide range.

Biosorption of chromium and nickel from aqueous solution using pine cones, eucalyptus bark, and moringa pods: a comparative study

AbstractLow-cost local plants (eucalyptus bark, moringa pods, pine cones) have been successfully used to remove heavy metals from simulated wastewater. Two types of heavy metals were chosen to study the removal capacity, nickel (Ni) and chrome (Cr), with a concentration of 400, 600, 900 ppm. The results show that moringa pods have the best removal capacity for heavy metals with percentages of 90–99% for both metals, Ni and Cr, for the eucalyptus bark the removal capacity percentages reach 50–98%, while for the pine cones revealed a lower removing capacity with percentages of 40–99%, indicating that this is the lowest removal capacity. The data has been best fitted to the Langmuir adsorption model for all plants, while the Freundlich adsorption model could not fit the obtained results at the experimental conditions. The kinetic study has revealed that the first-order kinetic model successfully describes the kinetics of Ni adsorption, while the second-order describes the kinetics of Cr adsorption. The removal of heavy metals (Ni, Cr) was obtained when moringa was used; its highest removal efficiency was reached within 20 minutes. On the other hand, other plants (eucalyptus bark, pine cone) removal efficiency was attained in more than two hours. The removal is remarkable even at a high concentration of heavy metals, especially with the moringa plant.

Porous nanocomposite based on metal-organic framework: Antibacterial activity and efficient removal of Ni(II) heavy metal ion

In present work, a novel ZIF-8@SnO2@CoFe2O4 nanostructure was fabricated by hydrothermal rote and its ability was assessed for sorption of Ni2+ and disinfection of microorganisms. FTIR, XRD, DLS, SEM, TEM, BET and VSM analyses were utilized to confirm the characterization of the synthesized MOF. Performance of ZIF-8@SnO2@CoFe2O4 for Ni(II) adsorption was investigated as a function of pH, dose, time, various Ni2+ concentrations and temperatures. The results exhibit that ZIF-8@SnO2@CoFe2O4 has a good performance for Ni2+ adsorption from an aqueous medium so that 60 min mixing of 40 mg of adsorbent with the 50 mg L−1 of pollutant at a pH = 6. Equilibrium tests detected that Sips isotherm had the best agreement to the experiment data with R2 of 0.9957. The maximum adsorption capacity was also obtained 21.43 mg g−1. The sorption kinetics followed the pseudo first order model. Thermodynamic study illustrated an endothermic and physisorption reaction for nickel sorption onto ZIF-8@SnO2@CoFe2O4. Results achieved from disc diffusion, MBC and MIC methods exhibited that ZIF-8@SnO2@CoFe2O4 led to excellent biocidal activities for selected strains of bacteria. Additionally, the highest radius of inhibition zone was measured for ZIF-8@SnO2@CoFe2O4 against Escherichia coli by disc diffusion test as 18 mm.

Ultrathin holey reduced graphene oxide/Ni(picolinic acid)2 papers for flexible battery-supercapacitor hybrid devices

Metal-organic frameworks have attracted great interest as a kind of promising electrode materials for electrochemical energy storage, due to their porous skeleton in favor of electrolyte ion diffusion for reversible redox reactions of metal ions, but usually suffer from poor conductivity and low packing density, to the disadvantage of boosting rate capability and volumetric capacitance. We report a novel flexible battery-supercapacitor hybrid (BSH) device based on the holey reduced graphene oxide (HRGO) anode and the HRGO/Ni(picolinic acid)2 (Ni(PA)2) cathode. The HRGO obtained by etching RGO with nitric acid through hydrothermal process, exhibits abundant micropores in favor of fast electrolyte ion diffusion. The ultrathin stratiform HRGO/Ni(PA)2 paper prepared through the adsorption of Ni2+ complex on HRGO and the hydrothermal process of HRGO/Ni2+ complex, can provide gravimetric and volumetric capacitances of 738 F g−1 at 1 A g−1 and 747 F cm−3 at 1 A cm−3. The assembled flexible BSH device can deliver the volumetric capacitance of 67.1 F cm−3 (at 0.79 A cm−3), rate capability of 80% (from 0.79 A cm−3 to 7.9 A cm−3), energy density of 23.7 Wh L-1 (at 632 W L-1), cycling stability of 83.3% (after 10,000 cycles), opening up new avenues for developing high-volumetric flexible energy storage devices.