Adsorption of Pb(II) from aqueous solution to Ni-doped bamboo charcoal

Towards sorptive eradication of pharmaceutical micro-pollutant ciprofloxacin from aquatic environment: A comprehensive review

Antibiotics are widely prioritized pharmaceuticals frequently adopted in medication for addressing numerous ailments of humans and animals. However, the non-judicious disposal of ciprofloxacin (CIP) with concentration levels exceeding threshold limit in an aqueous environment has been the matter of growing concern nowadays. CIP is found in various waterways with appreciable mobility due to its limited decay in solidified form. Hence, the effective eradication strategy of this non-steroidal anti-inflammatory antibiotic from aqueous media is pivotal for preventing the users and the biosphere from their hazardous impacts. Reportedly several customary techniques like reverse osmosis, precipitation, cross-filtration, nano-filtration, ion exchange, microbial remediation, and adsorption have been employed to eliminate CIP from water. Out of them, adsorption is ascertained to be a potential method because of lesser preliminary investment costs, ease of operation, greater efficiency, less energy usage, reduced chemical and biological slurry production, and ready availability of precursor materials. Towards remediation of ciprofloxacin-laden water, plenty of researchers have used different adsorbents. However, the present-day challenge is opting the promising sorbent and its application towards industrial scale-up which is vital to get reviewed. In this article, adsorbents of diverse origins are reviewed in terms of their performances in CIP removal. The review stresses the impact of various factors on sorptive assimilation of CIP, adsorption kinetics, isotherms, mechanism of ionic interaction, contrivances for CIP detection, cost estimation and reusability assessments of adsorbents also that may endorse the next-generation investigators to decide the efficacious, environmental appealing and cost-competitive adsorbents for effective riddance of CIP from wastewater.

Pb (II) Recovery by Modified Tuffite: Adsorption, Desorption, and Kinetic Study

In this study, Pb (II) removal from wastewater was investigated using a modified vitric crystal tuffite with a BET surface area of 11.7 m2/g. For this purpose, tuffite was used in its natural and modified form with ethylenediaminetetraacetic acid (EDTA). Batch adsorption experiment was performed. The effects of contact time (0–90 min), adsorbent dosage (1–10 g/L), initial concentration (10–200 mg/L), and pH (2–12) on the removal of Pb (II) were investigated. The isotherm data were fitted to Langmuir, Freundlich, Temkin, and Redlich-Peterson isotherm models. Kinetic models such as pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were used. In order to optimize the adsorption system and investigate the kinetic behaviour of adsorption, nonlinear isotherm and kinetic models were used as well as linearized models. Error analyses were made in order to express the obtained results more accurately. pH 5 was the optimum value for adsorption. According to nonlinear isotherm model calculations, Bayburt stone (BS) and its modified form (MBS) had $q_{\max }$ values of 335 and 584 mg/g, respectively. The Freundlich model, with its high correlation coefficients of about 1.00, was found to be more suitable for the adsorption of Pb (II) to MBS. The pseudo-second-order kinetic model with mean $R^2$ and $k_2$ values of 0.997 and 0.0116 1/min, respectively, was found to be more appropriate. According to the regeneration studies, the maximum desorption efficiency was 97.8%. The thermodynamic equilibrium coefficients obtained at different temperatures and $\Delta G^{\text{o}}$ , $\Delta H^{\text{o}}$ , and $\Delta S^{\text{o}}$ values were observed as -21.4, 46.4, and 163 kJ/mol, respectively. These values indicate that the adsorption of Pb (II) on to MBS was endothermic and spontaneous process. BS and MBS were characterized by different instrumental analyses such as SEM, EDS, FTIR, and zeta potential measurements.

Aluminum dispersed bamboo activated carbon production for effective removal of Ciprofloxacin hydrochloride antibiotics: Optimization and mechanism study

The central composite rotatable design (CCD) of response surface methodology (RSM) was used to optimize aluminum dispersed bamboo activated carbon preparation. The independent variables selected for optimization are activating agent (AlCl₃) concentration (mol/L), activation temperature (°C), and activation time (min.). The independent variable's response change was observed through the percentage adsorption efficiency of Ciprofloxacin hydrochloride (CIP) antibiotics. The maximum CIP adsorption efficiency was found to be 93.6 ± 0.36% (13.36 mg/g) for the adsorbent prepared at AlCl₃ concentration 2.0 mol/L, activation temperature 900 °C, and activation time 120 min. The adsorption efficiency was recorded at the natural pH (7.9) of the adsorbent (3 g/L)-adsorbate (50 mL solution of 50 ppm) mixture. The Al-dispersed bamboo activated carbon was characterized for its surface morphology, surface elemental compositions, molecular crystallinity, surface area, pore morphology, and surface functional groups. The mechanism of adsorbent surface formation and CIP adsorption sites were explored. The characterization data and mechanism study will help in deciding possible future applications in other fields of study.

Adsorption Phenomenon of Arundinaria alpina Stem-Based Activated Carbon for the Removal of Lead from Aqueous Solution

In this study, activated carbon was prepared from locally available bamboo (Arundinaria alpina) in Ethiopia to remove Pb (II) from wastewater. Various effects such as solution pH, initial Pb (II) ion concentration, and adsorbent dose were investigated and accordingly discussed, and the process was carried out on a batch adsorption base. Dried Arundinaria alpina stem was activated with potassium hydroxide (KOH) at a ratio of 1 : 1 (w/v) and carbonized in a furnace at three temperature ranges (500oC, 600oC, and 700oC) for 3 h. The physicochemical of Arundinaria alpina stem activated carbon (AASAC) was investigated and the resultant of 500oC treatment setup is found as ideal in terms of yield (40.6 g), ash (3.5%), porosity (0.704%), moisture (7.7%), and iodine number (814.69 mg/g). The further characterization of ideal AASAC was carried out by scanning electron microscopy (SEM), X-ray diffraction (XRD) spectroscopy, and Fourier transform infra-red (FTIR). The optimum Pb (II) removal efficiency of AASAC was 99.8% at pH 5 in a synthetic solution, but the efficiency declined to 60.42% on real industrial wastewater due to the presence of its mixed pollutant nature. Freundlich isotherm model is more favorable than Langmuir with a high correlation coefficient (R2-0.9496) for Pb (II) adsorption. The study revealed that AASAC has a potential adsorption efficiency to remove the Pb (II) ion from the aqueous solution which is also recommended as an adsorbent for real industry wastewater treatment.

Critical review of magnetic biosorbents: Their preparation, application, and regeneration for wastewater treatment

The utilisation of magnetic biosorbents (metal or metal nanoparticles impregnated onto biosorbents) has attracted increasing research attention due to their manipulable active sites, specific surface area, pore volume, pore size distribution, easy separation, and reusability that are suitable for remediation of heavy metal(loid)s and organic contaminants. The properties of magnetic biosorbents (MB) depend on the raw biomass, properties of metal nanoparticles, modification/synthesis methods, and process parameters which influence the performance of removal efficiency of organic and inorganic contaminants. There is a lack of information regarding the development of tailored materials for particular contaminants and the influence of specific characteristics. This review focuses on the synthesis/modification methods, application, and recycling of magnetic biosorbents. In particular, the mechanisms and the effect of sorbents properties on the adsorption capacity. Ion exchanges, electrostatic interaction, precipitation, and complexation are the dominant sorption mechanisms for ionic contaminants whereas hydrophobic interaction, interparticle diffusion, partition, and hydrogen bonding are the dominant adsorption mechanisms for removal of organic contaminants by magnetic biosorbents. In generally, low pyrolysis temperatures are suitable for ionic contaminants separation, whereas high pyrolysis temperatures are suitable for organic contaminants removal. Additionally, magnetic properties of the biosorbents are positively correlated with the pyrolysis temperatures. Metal-based functional groups of MB can contribute to an ion exchange reaction which influences the adsorption capacity of ionic contaminants and catalytic degradation of non-persistent organic contaminants. Metal modified biosorbents can enhance adsorption capacity of anionic contaminants significantly as metal nanoparticles are not occupying positively charged active sites of the biosorbents. Magnetic biosorbents are promising adsorbents in comparison with other adsorbents including commercially available activated carbon, and thermally and chemically modified biochar in terms of their removal capacity, rapid and easy magnetic separation which allow multiple reuse to minimize remediation cost of organic and inorganic contaminants from wastewater.

Graphene oxide wrapped melamine sponge as an efficient and recoverable adsorbent for Pb(II) removal from fly ash leachate

Lead is one of the most toxic elements, which has been well recognized for its negative effect on the environment and human beings. But, preliminary methods such as chemical precipitation, membrane separation etc. and commonly used adsorbents based on adsorption technology were found to be expensive and inefficient. In this study, we modify the surface of melamine sponge (MS) with polydopamine (PDA) and then coat with glutathione/graphene oxide (GG) as the adsorbent (MS@GG) to removal Pb(II) from aqueous solutions and fly ash leachate. The maximum adsorption capacity of MS@GG was calculated to be 349.7 mg Pb/g GG, and the reaction reached equilibrium in 30 min which were both higher than raw GG material and most previously reported adsorbents due to active sites on the surface of GG, as well as the unique macroporous and hydrophilic structure of MS. Meanwhile, based on its easy separation, by using HCl as the regeneration agent, the materials revealed good reproducibility. In addition, when MS@GG was applied for the removal of Pb(II) in fly ash leachate, the removal efficiency reached up to 99.24%, indicating that the novel MS@GG was the promising candidate adsorbent material for Pb(II) removal.

Adsorptive Removal of Methylene Blue Using Magnetic Biochar Derived from Agricultural Waste Biomass: Equilibrium, Isotherm, Kinetic Study

Wastewater discharge from textile industries contribute much to water pollution and threaten the aqua ecosystem balance. Synthesis of agriculture waste based adsorbent is a smart move toward overcoming the critical environmental issues as well as a good waste management process implied. This research work describes the adsorption of methylene blue dye from aqueous solution on nickel oxide attached magnetic biochar derived from mangosteen peel. A series of characterization methods was employed such as FTIR, FESEM analysis and BET surface area analyzer to understand the adsorbent behavior produced at a heating temperature of 800[Formula: see text]C for 20[Formula: see text]min duration. The adsorbate pH value was varied to investigate the adsorption kinetic trend and the isotherm models were developed by determining the equilibrium adsorption capacity at varied adsorbate initial concentration. Equilibrium adsorption isotherm models were measured for single component system and the calculated data were analyzed by using Langmuir, Freundlich, Tempkin and Dubinin–Radushkevich isotherm equations. The Langmuir, Freundlich and Tempkin isotherm model exhibit a promising R2-correlation value of more than 0.95 for all three isotherm models. The Langmuir isotherm model reflectsan equilibrium adsorption capacity of 22.883[Formula: see text]mg[Formula: see text]g[Formula: see text].

Adsorption of Pb(II) by a polyvinylidene fluoride membrane bearing chelating poly(amino phosphonic acid) and poly(amino carboxylic acid) groups

Pb(II) can cause a hazardous effect on ecosystem and public health due to its high biotoxicity. A polyvinylidene fluoride-type membrane bearing both poly(amino phosphonic acid) and poly(amino carboxylic acid) functional groups was fabricated for the purpose of Pb(II) removal from the aqueous solutions. The adsorption behaviors of the fabricated chelating membrane toward Pb(II) were studied by the series of static and continuous adsorption experiments. When the pH, adsorption equilibrium time, initial Pb(II) concentration, and temperature were 5.1, 300 min, 1.0 mmol g−1, and 298 K, respectively, Pb(II) uptake of the membrane was 1.1 mmol g−1. The presence of coexisting metal ions and complexing reagents decreased the Pb(II) uptake. The adsorption kinetic and isotherm adsorption followed pseudo-second-order equation and Langmuir model, respectively; this adsorption process showed a spontaneous and exothermic feature. The bed depth service time and Thomas models were suitable for describing obtained breakthrough curves.

Degradation of Orange G by Fenton-like reaction with Fe-impregnated biochar catalyst

This study was conducted to evaluate the catalytic activity of Fe-impregnated sugarcane biochar (FSB) for removing azo dye Orange G (OG) from solution under various Fenton-like oxidation conditions. The optimum molar Fe concentration for impregnation to achieve maximum catalytic activity of FSB in Fenton-like reaction with acceptable effluent Fe release was 0.25 M (163.4 Fe mg/g in FSB). High removal efficiency of 99.7% was achieved within 2 h of reaction at optimum conditions of 0.075 g/L H₂O₂, 0.5 g/L FSB for 0.1 g/L OG at initial pH 5.5 under 25 °C. For every 10 °C increase, the time for maximum OG degradation efficiency decreased by 0.5 h. The OG removal by FSB exhibited a slow induction reaction followed by fast OG decomposition. FSB can be used successively for at least 4 runs with >89.3% OG removal. The FSB was more economical, efficient, and recyclable than other conventional Fenton oxidation catalysts.

Amine-functionalized magnetic bamboo-based activated carbon adsorptive removal of ciprofloxacin and norfloxacin: A batch and fixed-bed column study

Amine-functionalized magnetic bamboo-based activated carbon (AFM-BAC) derived from bamboo products wastes were employed for effective adsorption of fluoroquinolone antibiotics ciprofloxacin (CIP) and norfloxacin (NOR) through batch processing. The effects of factors on the adsorption of both antibiotics were studied. The studies of various factors influencing the adsorption behavior indicated that the maximum adsorption capacities for two antibiotics adsorption were observed in weakly acidic condition and the adsorption amounts of two antibiotics increased with the increase of zwitterionic form, implying the importance of zwitterionic form, and the adsorption process is spontaneous and endothermic. The result of date indicated that adsorption of both two antibiotics onto the AFM-BAC better fits Langmuir isotherm model. The saturated magnetization of AFM-BAC reached 8.55 emu g^-1. A fixed-bed column adsorption with a bench-scale was carried out. Desorption and regeneration experiments showed that the AFM-BAC for both antibiotics could remain above 80% after five consecutive recycling cycles.

Multistage optimizations of slow pyrolysis synthesis of biochar from palm oil sludge for adsorption of lead

This research investigated the removal of lead (Pb²⁺) by a novel biochar derived from palm oil sludge (POS-char) by slow pyrolysis. Multistage optimizations with central composite design were carried out to firstly optimize pyrolysis parameters to produce the best POS-char for Pb²⁺ removal and secondly to optimize adsorption conditions for the highest removal of Pb²⁺. The optimum pyrolysis parameters were nitrogen flowrateof30mLmin^-1, heating rateof10°Cmin^-1, temperatureof500°C and timeof30min. The optimum Pb²⁺ adsorption conditions were concentrationof200mgL^-1, timeof60min, dosageof0.3g and pH of 3.02. The various functional groups within POS-char played a vital role in Pb²⁺ uptake. Regeneration was demonstrated to be feasible using hydrochloric acid. Adsorption equilibrium was best described by Freundlich model. At low concentration range, adsorption kinetic obeyed pseudo-first-order model, but at high concentration range, it followed pseudo-second-order model. Overall, the results highlighted that POS-char is an effective adsorbent for Pb²⁺ removal.

Synthesis and Characterization of Reduced Graphene Oxide-Supported Nanoscale Zero-Valent Iron (nZVI/rGO) Composites Used for Pb(II) Removal

Reduced graphene oxide-supported nanoscale zero-valent iron (nZVI/rGO) composites were prepared by chemical deposition method and were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, N₂-sorption and X-ray photoelectron spectroscopy (XPS). Operating parameters for the removal process of Pb(II) ions, such as temperature (20–40 °C), pH (3–5), initial concentration (400–600 mg/L) and contact time (20–60 min), were optimized using a quadratic model. The coefficient of determination (R² > 0.99) obtained for the mathematical model indicates a high correlation between the experimental and predicted values. The optimal temperature, pH, initial concentration and contact time for Pb(II) ions removal in the present experiment were 21.30 °C, 5.00, 400.00 mg/L and 60.00 min, respectively. In addition, the Pb(II) removal by nZVI/rGO composites was quantitatively evaluated by using adsorption isotherms, such as Langmuir and Freundlich isotherm models, of which Langmuir isotherm gave a better correlation, and the calculated maximum adsorption capacity was 910 mg/g. The removal process of Pb(II) ions could be completed within 50 min, which was well described by the pseudo-second order kinetic model. Therefore, the nZVI/rGO composites are suitable as efficient materials for the advanced treatment of Pb(II)-containing wastewater.

Adsorption behavior and mechanisms of ciprofloxacin from aqueous solution by ordered mesoporous carbon and bamboo-based carbon

The performances of ordered mesoporous carbon CMK-3 (OMC), bamboo-based carbon (BC), and these two kinds of adsorbents modified by thermal treatment in the ammonia atmosphere at high temperatures were evaluated for the removal fluoroquinolone antibiotic (ciprofloxacin) from aqueous solution. The adsorption behavior of ciprofloxacin (CIP) onto OMC and BC including adsorption isotherms and kinetics were investigated. The effect of various factors (pH, ionic strength and temperature) on the adsorption process was also investigated. The results demonstrated that the modified OMC and BC can further enhance the adsorption capacity due to introduce of alkaline nitrogen functionalities on the carbon surface. And their maximum adsorption capacity reached as high as 233.37mgg(-1) and 362.94mgg(-1) under the same experimental conditions, respectively. This is primarily ascribed to the positive effect of the surface basicity. The highest sorption was observed at the lowest solubility, which indicated that hydrophobic interaction was the dominant sorption mechanism for CIP uptake onto the four adsorbents. The adsorption data of antibiotics was analyzed by Langmuir and Freundlich model, and the better correlation was achieved by the Langmuir isotherm. The kinetic data showed that the adsorption of CIP onto OMC and BC follow closely the pseudo-second order model. The removal efficiency and adsorption capacity increased with increasing temperature. The results of thermodynamic study indicated that the adsorption process was a spontaneous and endothermic.

Bioframe synthesis of NF–TiO2/straw charcoal composites for enhanced adsorption-visible light photocatalytic degradation of RhB

N–F codoped TiO₂/straw charcoal composites (NF–TiO₂/SC) were synthesized using a simple, bioframe-assisted sol–gel method and confirmed by XRD, SEM, EDX, TEM, N₂ adsorption–desorption, Raman, FT-IR, XPS, and UV-vis DRS measurements.

Adsorption optimization of lead (II) using Saccharum bengalense as a non-conventional low cost biosorbent: isotherm and thermodynamics modeling

In the present study a novel biomass, derived from the pulp of Saccharum bengalense, was used as an adsorbent material for the removal of Pb (II) ions from aqueous solution. After 50 minutes contact time, almost 92% lead removal was possible at pH 6.0 under batch test conditions. The experimental data was analyzed using Langmuir, Freundlich, Timken and Dubinin-Radushkevich two parameters isotherm model, three parameters Redlich-Peterson, Sip and Toth models and four parameters Fritz Schlunder isotherm models. Langmuir, Redlich-Peterson and Fritz-Schlunder models were found to be the best fit models. Kinetic studies revealed that the sorption process was well explained with pseudo second-order kinetic model Thermodynamic parameters including free energy change (AG degrees), enthalpy change (AH degrees) and entropy change (AS degrees) have been calculated and reveal the spontaneous, endothermic and feasible nature of the adsorption process. The thermodynamic parameters of activation (deltaG(#), deltaH(#) and deltaS(#)) were calculated from the pseudo-second order rate constant by using the Eyring equation. Results showed that Pb (II) adsorption onto SB is an associated mechanism and the reorientation step is entropy controlled.

Adsorption-photodegradation of humic acid in water by using ZnO coupled TiO2/bamboo charcoal under visible light irradiation

ZnO coupled TiO2/bamboo charcoal (ZnO-TiO2/BC) was prepared using the sol-gel method combined with microwave irradiation. The ZnO-TiO2/BC and TiO2/BC were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), N2 adsorption (BET), and UV-vis diffuse reflectance spectroscopy (UV-vis-DRS). The ZnO dopant promoted the transformation of anatase TiO2 to rutile phase, and a significant red shift of absorption edge was brought out due to the interfacial coupling effect between ZnO and TiO2 particles. The BET specific surface area and total pore volume decreased with ZnO doping, indicating that some micropores were blocked. SEM studies indicated that ZnO was almost uniformly deposited on the surface of the ZnO-TiO2/BC. The adsorption and photocatalytic degradation experiments showed that the photo-degrade efficiency for Zno-TiO2/BC was higher than that of TiO2/BC, and for both composites, the removal efficiency of HA increased as pH decreased from 10.0 to 2.0. The degradation of HA by ZnO-TiO2/BC and TiO2/BC fitted well with the Langmuir-Hinshelwood kinetics model, and HA degradation was achieved through a synergistic mechanism of adsorption and photocatalysis. ZnO-TiO2/BC could be used as an effective and alternative photocatalyst for the treatment of water contaminated by organic pollutants.