Biosorption Kinetics Research Articles

Lead removal from synthetic wastewater by biosorbents prepared from seeds of Artocarpus Heterophyllus and Syzygium Cumini

The present investigation deals with removal of lead (Pb+2) ions from waste water using biosorbent prepared from seeds of Artocarpus heterophyllus (SBAh) and Syzygium cumini (SBSc). Biosorbents surface has been characterized through FT-IR spectroscopy to probe the presence of functional groups. Response surface methodology enabled optimized conditions (Pb+2 concentration 2 μg/mL, pH 5.8 and bioadsorbent dose 60 mg) resulted in Pb+2 removal ~96% for SBAh and ~93% for SBSc at agitation speed 300 rpm. The adsorption capacity has been found to be 4.93 mg/g for SBAh and 3.95 mg/g for SBSc after 70 min. At optimal experimental conditions, kinetics of biosorption was explained well by inter-particle diffusion model for SBAh (R2 = 0.99) whereas Elovich model best fitted for SBSc (R2 = 0.98). Further, both the biosorbents followed Temkin adsorption isotherm model.

Kinetic modeling of biosorption for hydrocarbons removal from wastewater using modified logistic equation

Application of raw and modified biomass to remove hydrocarbons from wastewater by adsorption is a common practice. A mathematical modeling of biosorption kinetics is a crucial step to optimize the remediation process. In the present study, kinetic studies were carried out to describe the sorption process of crude oil and water on waste sunflower pith. To increase sorption capacity the pith surface was modified with polydimethylsiloxane (PDMS) and hydrophobic SiO2 nanoparticles. The maximum sorption capacity of raw and modified material was 17.76 and 19.62 g/g for crude oil, respectively. The system reached the equilibrium stage after 24 hours. The uptake profiles have been described by the pseudo-first order rate equation and the pseudo-second order rate equation. The calculated results were compared with experimental data and their fit was poor. To predict biosorption kinetics a new mathematically efficient procedure based on modified logistic equation was developed. The results indicate that the sunflower pith has a great potential for the removal of crude oil from water phase as an eco-friendly process.

Biosorption potential of brown algae, Sargassum polycystum, for the removal of toxic metals, cadmium and zinc.

In this research work, the biosorption potential of brown algae, Sargassum polycystum, was investigated for the removal of toxic metals, cadmium (Cd) and zinc (Zn), under controlled environmental conditions. The biosorbent prepared from the S. polycystum was characterized by Brunauer-Emmett-Teller (BET), scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) techniques. The optimal conditions identified using Box-Behnken design (BBD) for Cd removal were pH: 4.65, biosorbent mass: 1.8 g/L and shaking speed: 76 rpm. For zinc, the optimum values were pH: 5.7, biosorbent mass: 1.2 g/L and shaking speed: 125 rpm, respectively. The equilibrium uptake of the metals, Cd and Zn, was evaluated by isotherm models. The Langmuir isotherm proved to be an excellent fit confirming single layer of sorption. The maximum Cd and Zn uptakes achieved were 105.26 mg/g and 116.2 mg/g respectively. The kinetics of Cd and Zn biosorption onto brown algae Sargassum polycystum, follows pseudo-second order. The thermodynamic parameters were determined, and the sorption process was found to be feasible. Desorption studies of Cd and Zn were performed, and the bio sorbent reproduced appreciable efficiency for five successive cycles of sorption-desorption process using HCl.

Simultaneous removal of heavy metals from drinking water by banana, orange and potato peel beads: a study of biosorption kinetics

Banana, orange and potato peels (BP, OP and PP, respectively) were immobilised to produce biosorbent beads that were employed for the biosorption of heavy metals from a cocktail solution containing As(V), Cd(II), Cr(VI), Cu(II), Hg(II) and Ni(II) ions. Drinking water conditions were maintained with neutral initial pH and low concentration of the ions. Batch experiments were performed for evaluating the effect of pH in the drinking water range (6.5–8.5). Results showed a significant increase in the biosorption capacity of the beads with respective to the uptake of As and Pb, whereas it decreased significantly for Cd, Cu, Hg and Ni ions at basic pH values. Approximate equilibrium biosorption of Cd, Cu, Hg and Ni was 89–92%, 79–87%, 84% and 71–80% by BP, OP and PP beads. The physisorption-based PFO model was the most suitable for the ions with biosorption capacities closer to the experimental values. BP and OP beads had better biosorption efficiencies relative to PP bead due to the higher surface heterogeneity observed by scanning electron microscopy coupled with energy-dispersive spectroscopy. An increase in the biosorbent concentration from one to ten BP beads significantly increased the biosorption percentage of the ions. The biosorption capacities of Cd, Hg and Ni uptake by one BP bead from a 1 mgL−1 cocktail solution were 3.4 ± 0.0, 5.3 ± 0.1 and 3.0 ± 0.0 mgg−1, respectively. Thus, BP beads were the most effective than for the simultaneous removal of heavy metals from drinking water.

Cu transport and distribution in different cellular fractions of Klebsiella oxytoca strain CAV 1374

This study elucidated copper (Cu) transport and trafficking mechanisms at the cellular interface using the Cu-resistant strain Klebsiella oxytoca CAV 1374. The optimum conditions for biosorption were determined by investigating uptake rates due to initial pH, initial Cu concentrations, and maximum tolerated concentrations (MTC) of Cu. Cellular fraction analysis and depth-profiling XPS were used to comprehensively evaluate the spatial-temporal distribution of Cu on cellular interfaces during biosorption. Potential uptake mechanisms were then further examined by biosorption kinetics analyses, ion exchange experiments, FTIR analysis, and K+ channel blocking experiments. The results indicated that Cu was primarily absorbed by extracellular polymeric substances through chemical interactions and little Cu penetrated inside cells under low Cu stress conditions (≤20 mg/L). In contrast, an intracellular rate-controlling physical interaction was predominant under high Cu stress conditions (≥30 mg/L). Further, Cu2+ could be bound by functional groups, followed first by replacement of Ca2+ at the cell surface. Subsequently, some of the Cu2+ in cell walls was reduced to Cu+, and only Cu+ could then penetrate into cell membranes. These results indicate that strain Klebsiella oxytoca CAV 1374 is a suitable biosorbent agent for Cu removal and can provide critical insights into Cu-uptake mechanisms of microorganisms.

Attached culture of Gibberella fujikuroi for biocomposite sorbent production and ciprofloxacin sequestration applications

AbstractBACKGROUNDThe fluoroquinolone antibiotics in water sources are significant threats to public health, as well as the water ecosystem and water reuse. In this study, the feasibility of the biosorption of ciprofloxacin (CIP) using pine needles biomass‐Gibberella fujikuroi immobilized biocomposite (PNGFB) was promoted. It was prepared by passive cell immobilization onto the lignocellulosic matrix. The suggested biosorbent was characterized by Fourier Transform Infrared (FTIR) analysis, Scanning Electron Microscope (SEM), and zeta potential analysis. Series of batch and continuous mode experiments were conducted.RESULTSThe results of both systems showed that the PNGFB was effectively used for the treatment of CIP contamination. The maximum uptake occurred at pH 6.0, 40 min contact time, 1.0 mL min−1 flow rate, and 0.10 g (batch) and 0.20 g (column) PNGFB dosages. Redlich–Peterson isotherm model was the best suited to equilibrium data and the pseudo‐second‐order model predicted the biosorption kinetics. The maximum monolayer biosorption capability was 39.17 mg g−1. The suggested biocomposite also reached CIP removal yields of 64.14% and 53.74% in synthetic hospital effluent and synthetic urine samples containing 100 mg L−1 antibiotic, respectively. The regeneration study indicates that PNGFB retained its high biosorption and desorption yields during five cycles of the biosorption‐desorption.CONCLUSIONThe findings clearly showed that the PNGFB seems to be an eco‐friendly, effective, economic, and potentially viable biocomposite sorbent for the sustainable removal of CIP contamination. © 2021 Society of Chemical Industry (SCI).

Chitosan immobilization and Fe3O4 functionalization of olive pomace: An eco–friendly and recyclable Pb2+ biosorbent

An effective and sustainable biosorbent (MagOPIC) was prepared from chitosan and olive pomace by the combined action of immobilization and magnetic modification to remediate Pb2+-contaminated waters. Pb2+ sorption yield at the end of the equilibrium (45 min) period was estimated to be 98.56 ± 0.28% at pH 5.5. Agitation speed, ionic strength, and temperature did not significantly affect the Pb2+ biosorption. Biosorption kinetics are successfully fitted by the pseudo-second-order equation while the equilibrium biosorption data are properly modeled using the Freundlich and D–R isotherms. MagOPIC has also exhibited a high biosorption yield in the column tests (≥99%) and showed remarkable stability up to twenty consecutive regeneration cycles. Furthermore, it was successfully used for the treatment of Pb2+ containing real wastewater. The findings of this work highlighted the potential use of MagOPIC as a novel, cost-effective and eco-friendly biosorbent for the Pb2+ removal from the contaminated aquatic phase.

Removal of arsenic from aqueous solution by novel iron and iron–zirconium modified activated carbon derived from chemical carbonization of Tectona grandis sawdust: Isotherm, kinetic, thermodynamic and breakthrough curve modelling

The aim of the present study was: development of activated carbon modified with iron (Fe@AC) and modified with iron and zirconium (Fe–Zr@AC) from the Tectona grandis sawdust (TGS) waste biomass and its potential applicability for the removal of As (III) from contaminated water by batch and column mode. The biomass waste was pre-treated with ferric chloride (FeCl3) and the mixture of FeCl3 and zirconium oxide (ZrO2) and then pyrolyzed at 500 °C for 2 h. The properties of both bioadsorbents were comprehensively characterized by using Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX), Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), Particle Size analysis (PSA), point of zero charge (pHZPC), Brunauer–Emmett–Teller (BET) to prove successful impregnation of the Fe and Zr on the surface of AC of TGS. FTIR analysis clearly indicates the Fe and Fe–Zr complexation on biosorbents surface and biosorption of As (III). The results revealed that maximum As (III) removal was achieved 86.35% by Fe–Zr@AC (3 g/L dose, pH-7.0, temperature-25 °C and concentration 0.5 mg/L). However, maximum removal of As (III) was attained ~75% by Fe@AC (with dose-4g/L, pH-7.0, temperature-25 °C and concentration 0.5 mg/L) at the initial concentration of 0.5 mg/L of As (III). Fe–Zr@AC exhibits higher efficiency with qmax value 1.206 mg/g than Fe@AC with the qmax value 0.679 mg/g for the removal of As(III). While in the column study, Fe–Zr@AC exhibited 98.8% removal at flow rate of 5 mL/min and bed height of 5 cm. Biosorption Isotherm and Kinetics were fitted good with Langmuir isotherm (R2 ≥ 0.99) and followed pseudo-second-order (R2 ≥ 0.99). The regeneration study indicates that the prepared biosorbents efficiently recycled up to five cycles. Therefore, Fe@AC and Fe–Zr@AC derived from TGS has been showed to be novel, effective, and economical biosorbent. The collective benefits of easy development, good affinity towards As (III), good separability, reusability, and inexpensive of magnetized Fe@AC and Fe–Zr@AC make it a novel biosorbent. The application of Fe–Zr@AC for the removal of As (III) from the water was very efficient its concentration in the solution after treatment was found below the 10 μg/L as per the guideline WHO.

Comparative biosorption kinetics study of Ni and Zn metal ions from the aqueous phase in sulfate medium by the wooden biomass of Dalbergia sissoo

Comparative biosorption kinetics study of Ni and Zn metal ions from the aqueous phase in sulfate medium by the wooden biomass of <i>Dalbergia sissoo</i>

Lanthanum biosorption using sericin/alginate particles crosslinked by poly(vinyl alcohol): Kinetic, cation exchange, and desorption studies

Nowadays, lanthanum removal from wastewater has received attention due to its importance in various industrial applications. Biosorption has been considered a promising process for lanthanum removal from secondary sources. This study aimed to evaluate the use of sericin/alginate/poly(vinyl alcohol) (SAPVA) particles for lanthanum biosorption in batch system. The effect of pH on the biosorption of lanthanum showed that both lanthanum‐uptake (0.103 mol/kg) and calcium‐release (0.155 mol/kg) reach a maximum at equilibrium pH 5.22. Biosorption kinetics was carried in three lanthanum initial concentrations (0.0005, 0.0011, and 0.0017 mol/dm3). The results revealed that the equilibration time was reached between 210 and 450 min and biosorption capacity at equilibrium between 0.050 and 0.152 mol/kg. The kinetic followed the pseudo-second order model and the external diffusion was the main limiting step. Evaluation of cation exchange mechanism showed that the lanthanum biosorption is related to a stoichiometric reaction (2:3 ratio) between calcium and lanthanum. Calcium nitrate under acidic conditions was able to retrieve lanthanum biosorbed in the particles with high efficiency (96.07 ± 2.02%). Regeneration kinetics showed a longer equilibration time (630 min) and lower biosorption capacity at equilibrium (0.138 mol/kg) for the lanthanum initial concentration of 0.0015 mol/dm3. In this case, the experimental kinetic profile of calcium released throughout the lanthanum biosorption was not stoichiometric. Characterization analyzes suggest that the main mechanism involved in lanthanum capture and calcium release was cation exchange between functional groups on the biosorbent particles and lanthanum. Thus, SAPVA particles are a promising biosorbent for lanthanum removal from aqueous solutions.

Utilization of different parts of Moringa oleifera Lam. seeds as biosorbents to remove Acid Blue 9 synthetic dye

In this work, Moringa oleifera seed husk (MOSH) and Moringa oleifera seed pulp (MOSP) were converted via a green route into efficient biosorbents for biosorption of Acid Blue 9 (AB9) synthetic dye from the wastewater. The textural properties, morphologies, and structures of both biosorbents were analyzed using Fourier infrared spectroscopy (FTIR), N2 adsorption/desorption isotherms, pH of point-zero-charge (pHPZC), and scanning electron microscope (SEM). The characterization results showed that the biosorbents have heterogeneous surfaces with a diversity of functional groups. The experimental data of biosorption kinetics were best described by the nonlinear Avrami fractional. The isothermal empirical data were supported by the nonlinear Liu equation, and the maximum biosorption capacities of MOSH and MOSP at 55 °C for AB9 synthetic dye are 329.5 mg g–1 and 694.2 mg g–1, respectively. The evaluation of thermodynamic parameters showed that the biosorption processes of both biosorbents were spontaneous, endothermic, and occurred by physisorption. The availability, low-cost, high adsorption capacity, and fast adsorption kinetics of MOSH and MOSP make them alternative, promising, and attractive green biosorbents for removal AB9 synthetic dye from aqueous solutions.

Efficacy of green waste-derived biochar for lead removal from aqueous systems: Characterization, equilibrium, kinetic and application

The removal of toxic metals from the aquatic ecosystem is one of the most pressing environmental and public health concerns today. A strong potential has recently emerged for the removal of such metals using biochar sorbents. Biosorption technology could make a significant difference in the future. It is a viable and cost-effective alternative to the remediation of toxic pollutants utilizing various biomaterials. In the current study, batch and fixed−bed studies were performed to evaluate the performance of Capsicum annuum L. seeds biochar (CASB) as an alternative material in removing toxic Pb(II) from aqueous solutions. Removal characteristics were investigated by considering the equilibrium and kinetic aspects. Biosorption equilibrium was established within 40 min. The optimum dosage of CASB for Pb(II) removal was determined as 2.0 g L−1. Biosorption data were well predicted by a non−linear Langmuir isotherm model. Monolayer biosorption occurred for CASB with a maximum capacity of 36.43 mg g−1. Biosorption kinetics fitted well with a pseudo−first−order kinetic model. The external mass transfer may control Pb(II) transport mechanism. Dynamic flow mode biosorption and regeneration potential of CASB were also examined. The application of CASB exhibited a 100% removal yield in real apple juice samples spiked with low concentrations of Pb(II). Exhausted points for the CASB packed columns were recorded as 195 and 320 min for simulated wastewater (SW) and synthetic Pb(II) solution, respectively. FTIR, BET, SEM−EDX analysis, and zeta potential measurements were used for the characterization of biochar and assessment of the metal ion−biosorbent interaction mechanism. Finally, our study provides a practical approach for the uptake of Pb(II) ions from contaminated solutions.

Biosorption of oxybenzene using biosorbent prepared by raw wastes of Zea mays and comparative study by using commercially available activated carbon.

Organic pollutants present in waste water have undesirable effect on the environment. Industry activities are the key sources of organic pollutants. Prime pollutants released from various sources react instantly with the environment and become derived (secondary) pollutants, which stay for an elongated time. The present research work has been carried out using biosorbent prepared from various Zea mays wastes for elimination of oxybenzene. Different parameters viz contact time, initial concentration; adsorbent dose, temperature and pH were optimized for the biosorption of oxybenzene on to the biosorbent samples. BCS (Baby corn silk) showed higher percentage of biosorption at optimum contact time of 3 h, pH between 5 and 6 and temperature at 25 °C. Analysis of equilibrium biosorption data in terms of several isotherm models revealed that Langmuir isotherm and Freundlich isotherm indicates better agreement with the experimental data. The kinetics of oxybenzene biosorption on to the biosorbents was described with the pseudo-first-order model. Thermodynamic parameters indicated that biosorption onto biosorbent was feasible in nature, spontaneous, and endothermic for some biosorbents, but on contrary not feasible, exothermic and non spontaneous for other biosorbents. The result of this study showed that the biosorbent derived from Zea mays can be used as a prospective biosorbent for oxybenzene in wastewater and also can be an alternative for the commercially activated carbon.

Characterization of cadmium biosorption by inactive biomass of two cadmium-tolerant endophytic bacteria Microbacterium sp. D2-2 and Bacillus sp. C9-3.

In this study, two cadmium-tolerant endophytic bacteria (Microbacterium sp. D2-2 and Bacillus sp. C9-3) were employed as biosorbents to remove Cd(II) from aqueous solutions. The influence of initial pH, initial Cd(II) concentration, adsorbent biomass, temperature and contact time on Cd(II) removal were investigated. Results showed that the Langmuir isotherms were found to best fit the equilibrium data, and the maximum biosorption capacities were found to be 222.22 and 163.93 mg/g at a solution pH of 5.0 for Microbacterium sp. D2-2 and Bacillus sp. C9-3, respectively. The biosorption kinetics followed well pseudo-second-order kinetics. Fourier transform infrared spectroscopic analysis suggested that the hydroxyl, carboxyl, carbonyl and amino groups on Microbacterium sp. D2-2 and Bacillus sp. C9-3 biomass were the main binding sites for Cd(II). The results presented in this study showed that Microbacterium sp. D2-2 and Bacillus sp. C9-3 are potential and promising adsorbents for the effective removal of Cd(II) from aqueous solutions.

Bioremoval of Safranin O dye by the identified lichen species called Evernia prunastri biomass; biosorption optimization, isotherms, kinetics, and thermodynamics

Evernia prunastri (lichen), a novel, eco-friendly, cost-effective, wide availability, safe, renewable and easy collection biosorbent, has been utilized for the removal of Safranin O (SO) dye from an aqueous solution. The biosorption behavior of SO onto the lichen biomass was investigated concerning parameters such as initial SO concentration (10–2000 mg L−1), solution pH (2.0–12.0), lichen biomass dosage (1–20 g L−1), contact time (2–1440 min), temperature (5 °C, 25 °C, and 40 °C), and recovery were investigated. The zeta potential analyses showed that electrostatic attraction existed during the biosorption process between the SO and lichen biomass. The maximum SO biosorption capacity of the lichen biomass was 0.257 mol kg−1 at pH 6.0 and 25 °C. The biosorption energy for SO onto the lichen biomass was found to be EDR:8.9 kJ mol−1 reveals the biosorption proceeds chemically. The biosorption process follows the pseudo-second order and intra particle diffusion rate kinetics. Thermodynamic studies showed that SO biosorption, by this the lichen biomass is possible, spontaneous, and endothermic.

Pb (II) biosorption from the aqueous solutions by raw and modified tea factory waste (TFW)

The study is aimed to determine Pb (II) biosorption from synthetic wastewaters using natural and modified tea factory waste as biosorbent material. This process is carried out with this waste matter, which is found in large quantities, so cheap and has high metal adsorption ability. The sorption kinetic studies were determined as variations of initial pH value, particle size, initial Pb (II) and tea factory waste concentrations, stirring speed and temperature. Biosorption reached the equilibrium in 15 min. Zeta potential values of the biosorbent were defined in the range of pH 2 to 4. The adsorption isotherm models give the experimental values, and the thermodynamic characteristics of the patterns generally give insight about the sorption mechanism depending on the surface characteristics and affinity of the biosorbent. The biosorption mechanism was searched considering to Freundlich, Langmuir, BET and Temkin isotherm model, and the experimental adsorption values were conformed to Freundlich adsorption model. The optimum experimental conditions were investigated as pH 3.5, particle size of 0.125–0.25 mm, stirring speed of 200 rpm, biosorbent concentration of 7 g L−1 and 25 °C. In these conditions, the highest efficiency of biosorption was obtained as 94.07% and after the activating process the efficiency was reached to 97.73% at 70 mg L−1. The maximum Pb (II) removal capacity of raw tea factory waste was found to be 22.111 mg g−1 at 200 mg L−1. The biosorption kinetics has complied with the pseudo-second-order model. Thermodynamic studies stated that this biosorption phenomenon was an endothermic process.

Freezing/thawing pretreatment of dormant Aspergillus niger spores to increase the Cr(vi) adsorption capacity: process and mechanism.

Hexavalent chromium is a widespread pollutant that threatens ecological and human health. However, its removal from the environment is limited by the high cost and energy consumption rate of current technologies. In this study, the Cr(vi) biosorption mechanism of Aspergillus niger spores pretreated by freezing/thawing was studied by batch experiments and surface chemistry analyses. The results indicated that pretreatment enhanced the spores' Cr(vi) removal efficiency. The cell surface, internal functional groups, and morphology of the freezing/thawing-pretreated spores (FTPS) before and after Cr(vi) loading were characterized by advanced spectroscopy techniques such as SEM-EDAX, XPS, FTIR, and FETEM analyses. The SEM and BET data showed that the surface of FTPS was rougher than that of untreated spores. The XPS data showed that FTPS bio-transformed Cr(vi) into Cr(iii). The intracellular localization of chromium was visualized by FETEM, and both surface and intracellular structures removed Cr(vi) following pseudo-second-order biosorption kinetics. The biosorption dynamics of Cr(vi) fit the Langmuir isotherm model describing a monolayer. These results suggest that freezing/thawing pretreatment of A. niger spores could lead to the development of a novel, efficient biomaterial for the removal of Cr(vi).

Tetracycline removal from model aqueous solutions by pretreated waste Streptomyces fradiae biomass

Pretreated waste Streptomyces fradiae biomass was used as biosorbent to remove tetracycline (TC) from model aqueous solutions. The biosorption study was conducted in a batch system to evaluate the impact of initial pH, biosorbent dosage, initial TC concentration and contact time. Langmuir, Freundlich and Dubinin–Radushkevich (D–R) models were applied to describe the biosorption isotherm equilibrium studies. Langmuir and Freundlich models fitted the equilibrium data better than the D–R model. The monolayer biosorption capacity of the pretreated biomass for TC was 38.61 mg g−1. The experimental data were also tested in terms of biosorption kinetics using pseudo-first-order and pseudo-second order kinetics models. The results showed that the TC biosorption process followed well pseudo-second-order kinetics.

Effect of ultrasound on biosorption kinetics of Acid blue 25 from aqueous media by using cycads palm bark as novel biosorbent

Effect of ultrasound on biosorption kinetics of Acid blue 25 from aqueous media by using cycads palm bark as novel biosorbent

Enhanced adsorptive removal of crystal violet dye from aqueous media using citric acid modified red-seaweed: experimental study combined with RSM process optimization

Herein, we report the preparation of a novel biosorbent; a citric acid modified red-seaweed for crystal violet (CV) removal from water. Surface characterization and basic biosorption characteristics of pristine red seaweed (RS) and its citric acid-modified form (RS@CA) were critically evaluated through scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transformed infrared (FTIR) spectroscopy, and BET surface analysis. Batch experiments were, then, performed to evaluate the biosorption performance of adsorbent under various operational parameters. The CV biosorption kinetics and equilibrium data were fitted well by pseudo second order and Langmuir model for both RS and RS@CA, respectively. Optimum monolayer uptakes of RS and RS@CA for CV dye were 142.86 and 217.38 mg g−1, respectively. Thermodynamically, the biosorption process was found to be endothermic (ΔH° > 0) and spontaneous (ΔG° ˂ 0). The CV binding mechanism toward RS@CA surface sites was mainly manifested by the electrostatic driving force pathway. Response surface methodology calculations showed a maximum CV biosorption efficiency of 93.40% at optimum biosorption conditions: pH 7, biosorbent dose of 1.5 g L−1, initial CV concentration of 20 mg L−1, and adsorption time of 90 minutes at 20 °C. The regeneration data further indicated that RS@CA could be effectively reused up to five cycles, losing only 6.7% of the original CV removal efficiency. Finally, it was concluded that RS@CA could be used as a cost-effective, eco-friendly and recyclable biosorbent to remove CV dye from water.