Insights into the equilibrium, kinetic and thermodynamics of nickel removal by environmental friendly Lansium domesticum peel biosorbent

Kinetic process of the biosorption of Cu(II), Ni(II) and Cr(VI) by waste Pichia pastoris cells

Waste biomass of Pichia pastoris (P.pastoris) cells from the fermentation industry is an environmentally friendly biosorption material. The present study aimed to explore the biosorption behaviour of waste P.pastoris cells for Cu(II), Ni(II) and Cr(VI) in aqueous solution conditions. The results showed that the adsorption kinetics of three kinds of metals were well-fitted with lineared Elovich, pseudo-second-order kinetics models, non-linear kinetics and adsorption isotherms. The effective biosorption rates for Cu(II), Ni(II) and Cr(VI) removal were 71.3%, 59.7% and 16.25% respectively. The maximum Cu(II) adsorption capacity of waste P.pastoris was 40 mg/g at pH = 4 and 225 mg/L of solute concentration for 0.4 g biomass, better than that of the living yeasts. The pattern of Fourier transform infrared (FTIR) indicated that functional groups such as -NH, -OH, Si-O, P-O-C were involved in Cu(II) adsorption process. The analysis of SEM-EDS, XRD and TEM-EDS can be concluded that Cu(II) occupied Ca(II) binding sites by ion exchange mechanism to remove flocculation, and Cu(II) adsorbed onto the diatomite containing in the industrial waste P.pastoris. Thus the adsorption mechanism of the industrial waste P.pastoris was proposed taking Cu(II) as the example. And consecutive biosorption/desorption cycles were used for the evaluation of the regeneration efficiency, suggesting the good regeneration and reusability of waste P.pastoris.

Removal of lead from aqueous solutions using three biosorbents of aquatic origin with the emphasis on the affective factors

The biosorptive potentials of three aquatics-based biosorbents, including shells of a bivalve mollusk and scales of two fish species for Pb removal from aqueous solutions were evaluated, for the first time. A Box-Behnken design with the response surface methodology was used to investigate the effects of the seven important variables (contact time, temperature, initial concentration, dosage, size, salinity and pH) on the sorption capacity of the sorbents. Among the seven studied factors, the effects of biosorbent dosage, initial concentration and pH were significant for all the response variables, while biosorbent size was not significant for any of the responses. The initial concentration was the most influential factor. The presence of Pb ions on the surfaces of the biosorbents after the adsorption was clearly confirmed by the SEM-EDX and XRF analyses. The maximum sorption capacities of the biosorbents were comparable to the literature and the descending order was as follows: scales of Rutilus kutum and Oncorhynchus mykiss and the shells of Cerastoderma glaucum. The isotherm studies revealed Langmuir model applicability for the Pb adsorption by R. kutum and O. mykiss scales, while Freundlich model was fitted to the adsorption C. glaucum shells.

A TIE Approach to Identify Substances Causing Sediment Pore Water Toxicity After a Major Fire at Fuel Storage Tanks in the Port of Santos (SE, Brazil)

The major fire at the fuel storage tanks of a Chemical Terminal in April 2015 at the Port of Santos (SP), SE Brazil, potentially caused significant environmental impacts to the Santos Estuarine System (SES). The aim of the study was to identify the classes of substances causing pore water toxicity in the SES sediments in the vicinity of the port terminal before and after the incident using the TIE approach. Our results suggest that nonpolar compounds (e.g. PAHs, BTX, oil and grease) from the storage tanks that burned, and surfactants present in the formulation of foam fire extinguishing agents were the responsible for the sediment toxicity observed in the vicinity of the incident site. The contribution of metals to the toxicity related to the incident was ruled out. A long-term monitoring of the environmental effects of the incident is recommended since substances for which evidence of toxicity was found are toxic, persistent and can accumulate in the biota.

Application of Raw and Modified Pomegranate Peel for Wastewater Treatment: A Literature Overview and Analysis

The use of renewable substrates as biosorbents has a great attention in wastewater treatment. The pomegranate peel (PGP) constitutes one of these substrates. A review is carried out to investigate the potential of pomegranate peel (PGP) for wastewater treatment. Physical and chemical PGP properties are presented and compared to those of Tunisian pomegranate peel (El Gabsi). Raw and modified PGP performance and sorption capacity for metals, dyes, and organic pollutants are evaluated. Different experimental sorption conditions such as concentration, contact time, pH, temperature, and adsorbent dose used in the literature are illustrated. Studied and best-fitted kinetics and isotherm models to experimental data and thermodynamic parameters are compared. The effects of activating physical and/or chemical conditions on the activated PGP properties are presented. This paper reveals noteworthiness properties of raw PGP for wastewater treatment compared to this activated form. The comparison between activated and raw PGP morphology exhibits that the activation does not necessarily improve the PGP adsorption capacity. Despite a limited research carried out on the raw PGP biosorbent, it appears from this study that it has very good adsorption properties, making it a serious and low-cost renewable substrate toward practical applications in wastewater treatment compared to various other waste agricultural biomass.

Fruit and Vegetable Peels: Utilization of High Value Horticultural Waste in Novel Industrial Applications

Fruits and vegetables are the highly used food products amongst the horticultural crops. These items are consumed uncooked, nominally cooked or fully cooked, according to their nature and cooking process. With the change in diet habits and rising population, the production, as well as the processing of horticultural crops, has exponentially improved to meet its increasing demand. A large amount of peel waste is generated from fruit and vegetable-based industries and household kitchen and has led to a big nutritional and economic loss and environmental problems. Processing of fruits and vegetables alone generates a significant waste, which amounts to 25-30% of the total product. Most common wastes include pomace, peels, rind and seeds, which are highly rich in valuable bioactive compounds such as carotenoids, enzymes, polyphenols, oils, vitamins and many other compounds. These bioactive compounds show their application in various industries such as food to develop edible films, food industries for probiotics and other industries for valuable products. The utilization of these low-cost waste horticultural wastes for producing the value-added product is a novel step in its sustainable utilization. The present review intends to summarize the different types of waste originating from fruits as well as vegetables peels and highlight their potential in developing edible films, probiotics, nanoparticles, carbon dots, microbial media, biochar and biosorbents.

Adsorptive of Nickel in Wastewater by Olive Stone Waste: Optimization through Multi-Response Surface Methodology Using Desirability Functions

Pollution from industrial wastewater has the greatest impact on the environment due to the wide variety of wastes and materials that water can contain. These include heavy metals. Some of the technologies that are used to remove heavy metals from industrial effluents are inadequate, because they cannot reduce their concentration of the former to below the discharge limits. Biosorption technology has demonstrated its potential in recent years as an alternative for this type of application. This paper examines the biosorption process for the removal of nickel ions that are present in wastewater using olive stone waste as the biosorbent. Kinetic studies were conducted to investigate the biosorbent dosage, pH of the solution, and stirring speed. These are input variables that are frequently used to determine the efficiency of the adsorption process. This paper describes an effort to identify regression models, in which the biosorption process variables are related to the process output (i.e., the removal efficiency). It uses the Response Surface Method (RSM) and it is based on Box Benken Design experiments (BBD), in which olive stones serves as the biosorbent. Several scenarios of biosorption were proposed and demonstrated by use of the Multi-Response Surface (MRS) and desirability functions. The optimum conditions that were necessary to remove nickel when the dosage of biosorbent was the minimum (0.553 g/L) were determined to be a stirring speed of 199.234 rpm and a pH of 6.369. The maximum removal of nickel under optimized conditions was 61.73%. Therefore, the olive stone waste that was investigated has the potential to provide an inexpensive biosorbent material for use in recovering the water that the nickel has contaminated. The experimental results agree closely with what the regression models have provided. This confirms the use of MRS since this technique and enables satisfactory predictions with use of the least possible amount of experimental data.

The effect of biochar mild air oxidation on the optimization of lead(II) adsorption from wastewater

In the present study, the effects of mild air oxidation of a biochar produced by the Pyrovac Inc. pyrolysis process, on the adsorption of lead(II) from synthetic wastewater under batch experimental conditions have been investigated. The adsorption experiments were performed under several conditions suggested by the response surface methodology, which allowed finding the optimal conditions, in order to maximize the adsorption capacity (Q(mgg^-1)), as well as the extraction efficiency (E (%)). The optimal conditions of lead ions adsorption were as follows: pH = 5, agitation time = 300 min, adsorbent mass = 0.5 g (per 50 cm³ of solution), and lead initial concentration = 100gm^-3, resulted in an adsorption capacity of 7.9 mg g^-1. Equilibrium adsorption was then obtained by keeping pH and adsorbent mass at the optimal values and changing the lead initial concentration for a sufficient agitation time. Results showed that mild air oxidation increased the equilibrium adsorption capacity of biochar from 2.5 to 44 mg g^-1. Oxidized biochar after equilibrium adsorption was submitted to SEM/EDX and XPS analysis. From SEM it was found that lead particles were distributed heterogeneously after adsorption. From XPS analysis, it was revealed that the external surface of oxidized biochar particles becomes saturated for the initial point of equilibrium diagram, obtained at lead initial concentration of 100gm^-3, suggesting that for a higher concentration, the internal surfaces of particles participate in the cations adsorption. The participation of surface functional groups in the adsorption process showed that carbonyl, carboxylic, and aromatic rings of oxidized biochar were involved in the adsorption. This work suggests that the very simple process of mild air oxidation can be used instead of the usual costly chemical activation, in order to improve biochar cation exchange capacity.

Adsorptive behaviour of palm oil mill sludge biochar pyrolyzed at low temperature for copper and cadmium removal

In this work, the influence of pyrolysis temperature on the physicochemical properties of palm oil mill sludge biochar (POSB) and its adsorption properties towards cadmium (Cd) and copper (Cu) was investigated. Characterization experiments suggested that POSBs' surface functional groups play the major role in the adsorption process. POSB pyrolyzed at 400 °C showed the best characteristics for Cu and Cd removal. Adsorption study indicated that contact time and shaking speed enhances the adsorption capacity of POSB. It was affirmed that pH adjustment is not necessary for POSB to adsorb Cu and Cd. Mechanism studies fitted well with Langmuir and Pseudo-Second Order model. Thermodynamic parameters indicated that the adsorption was spontaneous, endothermic and correspond to chemical adsorption. The highest uptakes of Cu and Cd were recorded at 48.8 mg/g and 46.2 mg/g respectively. This work verifies that the temperature used for palm oil mill sludge (POS) pyrolysis and adsorption condition played the most prominent role in Cu and Cd removal from aqueous solutions.

Environmental application of three-dimensional graphene materials as adsorbents for dyes and heavy metals: Review on ice-templating method and adsorption mechanisms

The remediation of wastewater requires treatment technologies which are robust, efficient, simple to operate and affordable such as adsorption. Lately, three-dimensional (3D) graphene based materials have attracted significant attention as effective adsorbents for wastewater treatment. The intrinsic properties of 3D graphene structure such as large surface area and interconnected porous structure can facilitate the transport of pollutants into the 3D network and provide abundant active sites for trapping the pollutants. For the synthesis of 3D graphene structure, ice-templating is commonly practiced due to its facile steps, cost effectiveness and high scalability potential. This review covers the ice-templating fabrication technique for 3D graphene based materials and their application as adsorbents in eliminating dyes and heavy metals from aqueous media. The assembly mechanisms of the ice-templating fsynthesis are comprehensively discussed. Further discussion on the fundamental principles, critical process parameters and characteristics of ice-templated 3D graphene structures is also included. A thorough review on the mechanisms for batch adsorption of dyes and heavy metals is presented based on the structures and properties of the 3D graphene materials. The review further evaluates the dynamic adsorption in packed columns and the regeneration of 3D graphene based materials.

Potentiality of white-rot fungi in biosorption of nickel and cadmium: Modeling optimization and kinetics study

The present study aimed to analyze simultaneous biosorption of Cd⁺² and Ni⁺² by living Phanerochaete chrysosporium as low-cost and eco-friendly biosorbent following optimization by applying a central composite design. The effect of operating parameters such as solution pH (4.0-8.0), temperature (20-40 °C), contact time (3-15 h), initial Cd⁺² and Ni⁺² concentrations (15-35, 5-25 mg L^-1, respectively) was evaluated by response surface methodology (RSM) for optimizing biosorption process. The Cd⁺² and Ni⁺² ions at 25 and 16 mg L^-1 were accumulated in P. chrysosporium with the efficiency of 96.23% and 89.48%, respectively, at pH of 6 and 36 °C after around 9 h under well mixing. The equilibrium data were fitted well with Langmuir isotherm model with maximum biosorption capacity of 71.43 and 46.50 mg g^-1 for Cd⁺² and Ni⁺², respectively. In addition, the pseudo-second order kinetic model could describe the kinetic data adequately. Further, possible interaction pathway among metals and P. chrysosporium functional groups were studied by Fourier transform infrared (FT-IR) spectroscopy. Furthermore, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) techniques were applied for morphology investigation and semi elemental analysis.

Evaluation of Cd(II) Ion Removal from Aqueous Solution by a Low-Cost Adsorbent Prepared from White Yam (Dioscorea rotundata) Waste Using Batch Sorption

An agricultural residue, white yam (Dioscorea rotundata) tuber peel (YTBS), was used for the removal of Cd(II) ion from an aqueous solution using a batch method. The adsorbent was characterized using FTIR, TGA, SEM, EDX, N2 BET, XRD, and XRF. The optimization of sorption variables such as pH, contact time, adsorbent dose, and initial metal ion concentration at 25 °C were also carried out. The results indicated the dependence of sorption on the adsorbate pH and adsorbent dose, while the adsorption system reached equilibrium in 180 min. The sorption kinetics was fitted to three models (pseudo first order, pseudo second order, and Elovich) to validate the kinetics, and the pseudo first order was the best model for the description of Cd(II) uptake. Equilibrium isotherm modelling was also carried out using the Langmuir, Freundlich, and Temkin models, with the Langmuir isotherm giving the best fitting to the experimental results. The maximum loading capacity (qmax) of the adsorbent for Cd(II) obtained from the Langmuir isotherm model was 22.4 mg∙g−1 with an isotherm constant (KL) of 3.46 × 10−3 L·mg−1 and r2 value of 0.99. This result indicates that the YTBS residue was a good adsorbent for the removal of Cd(II) ion from aqueous system.

Heavy metals uptake on Malpighia emarginata D.C. seed fiber microparticles: Physicochemical characterization, modeling and application in landfill leachate

Environmental heavy-metals contamination is a worldwide concern and the treatment of their sources constitutes a sustainable and efficient alternative. This work investigated the performance of Malpighia emarginataD.C. seed fibers microparticles (Me-SFMp) as biosorption platform for heavy metal ions. Integrated physicochemical analyses (FAAS, FTIR, SEM/EDS and XRF) showed that such ability was associated with the high microstructural porosity, wide surface area and diversity of functional groups on Me-SFMp structures, which favored the high and fast uptake of the target-substances (Cd, Zn, Cr, Pb, Cu and Ni ions). In terms of reactional kinetics, the pseudo-second order model showed better data correlation (R² from 0.9992 to 0.9998) and suggested the chemisorption as limiting step of the reaction mechanisms. From the Langmuir isotherms (R² from 0.9993 to 0.9998), it was observed that these phenomena occurred non-linearly on a homogeneous biosorbent monolayer. Me-SFMp can also be reused after desorption processes conducted in acid medium and, under ideal conditions (0.8 g biosorbent dosage; 100 mL of 1.00 mg L^-1 multi-metal solution adjusted to pH = 8.0; 300 rpm stirring speed; and 60 min contact time), the following maximum removal percentages order was observed for the first cycle: Cd (100%) = Zn (100%) > Cr (95.1%) > Pb (86.8%) > Cu (84.2%) > Ni (81.0%). The procedure was successfully applied to remove the studied heavy metal ions from raw landfill leachate, even in the presence of several (in)organic interferers, reinforcing the strong biosorbent-adsorbate interaction and the viability of this proposal.

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.

Packed-bed column biosorption of chromium(VI) and nickel(II) onto Fenton modified Hydrilla verticillata dried biomass

The present study represents the first attempt to investigate the biosorption potential of Fenton modified Hydrilla verticillata dried biomass (FMB) in removing chromium(VI) and nickel(II) ions from wastewater using up-flow packed-bed column reactor. Effects of different packed-bed column parameters such as bed height, flow rate, influent metal ion concentration and particle size were examined. The outcome of the column experiments illustrated that highest bed height (25cm); lowest flow rate (10mLmin(-1)), lowest influent metal concentration (5mgL(-1)) and smallest particle size range (0.25-0.50mm) are favourable for biosorption. The maximum biosorption capacity of FMB for chromium(VI) and nickel(II) removal were estimated to be 89.32 and 87.18mgg(-1) respectively. The breakthrough curves were analyzed using Bed Depth Service Time (BDST) and Thomas models. The experimental results obtained agree to both the models. Column regeneration experiments were also carried out using 0.1M HNO3. Results revealed good reusability of FMB during ten cycles of sorption and desorption. Performance of FMB-packed column in treating secondary effluent was also tested under identical experimental conditions. Results demonstrated significant reduction in chromium(VI) and nickel(II) ions concentration after the biosorption process.