Adsorbents for Water and Wastewater Treatment and Resource Recovery - Volume II

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Wastewater Treatment and Reuse".

Deadline for manuscript submissions: closed (15 December 2023) | Viewed by 24813

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Laboratory of Separation and Reaction Engineering—Laboratory of Catalysis and Materials (LSRE-LCM), Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
Interests: adsorption; wastewater treatment; natural adsorbents; toxic metalloids; metal recovery
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CNR Nanotec Institute of Nanotechnology, Via Monteroni, 73100 Lecce, Italy
Interests: composites; carbon nanomaterials; environmental remediation; electrochemistry; sensors; biomedicine
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Laboratory of Separation and Reaction Engineering—Laboratory of Catalysis and Materials (LSRE-LCM), Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
Interests: water and wastewater treatment; adsorption; low-cost materials; removal of heavy metals; nutrient recovery
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Adsorption is a well-established operation commonly used for water decontamination. Owing to its simplicity, ease of operation, effectiveness and selectivity, it is usually applied for the removal of odor, taste, toxic metals, radionuclides, nutrients, pharmaceuticals, pesticides, and other emerging contaminants from water. Adsorption has been ever more considered on the separation and recovery of substances of economical importance, or at risk of scarcity, such as phosphate and technology metals.

The global demand of safe water makes it imperative to treat effluents efficiently and to reuse water. The development and usage of alternative adsorbents for these purposes have captured scientific interest, motivated by the transition to a sustainable circular economy and the need of greener adsorbents.

With the success of the first volume of the Special Issue "Adsorbents for Water and Wastewater Treatment and Resource Recovery", the second volume of this special issue invites the submission of original research and review papers, covering current research and applications on adsorbents for water treatment and resource recovery. Contributions may focus on (but are not limited to) the use, synthesis/preparation and characterization of adsorbents such as biochar, biosorbents, clays, metal-organic frameworks, nanomaterials, composite and functional materials. Studies covering different organic or inorganic adsorbates, in view of decontamination of drinking-water and the treatment of irrigation water, industrial effluents, mining and landfill leachates are welcome. After a first special issue, “Adsorbents for water treatment and resource recovery II” will be especially receptive to contributions reporting case studies, continuous adsorption processes, regeneration and recovery assessments, process design, modeling and simulation, economic analysis and life-cycle assessments applied at the different developing stages of adsorbent synthesis and usage.

Dr. Sílvia Santos
Dr. Antonio Turco
Dr. Ariana Pintor
Guest Editors

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Keywords

  • adsorption
  • pollutants
  • metals
  • nutrients
  • emerging contaminants

Published Papers (12 papers)

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Research

14 pages, 4598 KiB  
Article
Sorption of Selenium(IV) and Selenium(VI) onto Iron Oxide/Hydroxide-Based Carbon Materials: Activated Carbon and Carbon Foam
by Lucia López-Toyos, Elena Rodríguez, Roberto García, Maria Rosa Martínez-Tarazona and Maria Antonia López-Antón
Water 2023, 15(19), 3499; https://doi.org/10.3390/w15193499 - 07 Oct 2023
Viewed by 876
Abstract
Selenium pollution in water is a worldwide issue. Se(IV) and Se(VI) are mainly found in contaminated water due to their high solubility and mobility; their presence poses a serious risk as they can severely harm human health. Although iron oxide and hydroxide nanoparticles [...] Read more.
Selenium pollution in water is a worldwide issue. Se(IV) and Se(VI) are mainly found in contaminated water due to their high solubility and mobility; their presence poses a serious risk as they can severely harm human health. Although iron oxide and hydroxide nanoparticles can be efficient candidates for the removal of selenium oxyanions due to their high adsorption capacity, the role of each iron species has not been fully elucidated. Furthermore, iron species are often found to be less effective for Se(VI) than Se(IV). The challenge and novelty of this study was to develop a carbon material impregnated with different iron phases, including oxides (magnetite/hematite) and hydroxides (goethite/lepidocrocite) capable of removing both Se(IV) and Se(VI). Since the phase and morphology of the iron nanoparticles play a significant role in Se adsorption, the study evaluated both characteristics by modifying the impregnation method, which is based on an oxidative hydrolysis with FeSO4 7H2O and CH3COONa, and the type of carbonaceous support (activated carbon or sucrose-based carbon foam). Impregnated activated carbons provide better removal efficiencies (70–80%) than carbon foams (<40%), due to their high surface areas and point zero charges. These results show that the adsorption of Se(VI) is more favorable on magnetic oxides (78%) and hydroxides (71%) than in hematite (<40%). In addition, the activated carbon decorated with magnetite showed a high adsorption capacity for both selenium species, even in alkaline conditions, when the sorbent surface is negatively charged. A mechanism based on the adsorption of inner-sphere complexes was suggested for Se(IV) immobilization, whereas Se(VI) removal occurred through the formation of outer-sphere complexes and redox processes. Full article
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17 pages, 4721 KiB  
Article
Preparation of ZnMgAl-Layered Double Hydroxide and Rice Husk Biochar Composites for Cu(II) and Pb(II) Ions Removal from Synthetic Wastewater
by Muhammad Shafiq, Abdulrahman Ali Alazba and Muhammad Tahir Amin
Water 2023, 15(12), 2207; https://doi.org/10.3390/w15122207 - 12 Jun 2023
Cited by 2 | Viewed by 1585
Abstract
The efficiency of a new composite material of the layered double hydroxide (LDH) of ZnMgAl and rice husk biochar (RHB) for the removal of Cu(II) and Pb(II) ions from synthetic wastewater was investigated in this study. The images of the scanning electron microscope [...] Read more.
The efficiency of a new composite material of the layered double hydroxide (LDH) of ZnMgAl and rice husk biochar (RHB) for the removal of Cu(II) and Pb(II) ions from synthetic wastewater was investigated in this study. The images of the scanning electron microscope showed extremely fine crystalline LDH particles decorated on the rough surface of the RHB, while the successful formation of the composite adsorbent (LDH/RHB) was confirmed by the corresponding energy dispersive X-ray and the Fourier-transform infrared spectroscopy. An equilibrium contact time of 30 and 15 min for Cu2+ and Pb2+, respectively, was proposed for the optimum performance of the batch adsorption process. The dose of the LDH/RHB adsorbent was optimized at 0.4 g L−1 yielding maximum adsorption capacities of 117 and 124 mg g−1 for Cu2+ and Pb2+, respectively, with corresponding maximum removal efficiencies of nearly 94% and 99%. A solution pH of 6.0 yielded optimum results with an increasing trend in adsorption capacities and percentage removal by changing the solution pH from 2.0 to 7.0. Based on the best fit of the pseudo-second-order kinetic model to the experimental data, chemisorption was suggested to be the controlling mechanism of adsorption. The fitting of the Langmuir model suggested a monolayer sorption of Cu2+ and Pb2+, and the application of the Dubinin–Radushkevich isotherm proposed physical adsorption. Full article
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17 pages, 2773 KiB  
Article
Competitive Adsorption of Drugs from a Multi-Component Mixture on Sugarcane Bagasse
by Maria E. Peñafiel and Damián Flores
Water 2023, 15(11), 2127; https://doi.org/10.3390/w15112127 - 03 Jun 2023
Cited by 2 | Viewed by 1607
Abstract
This work examines the adsorption in single- and multi-solute adsorption experiments of antibiotic and non-steroidal anti-inflammatory drugs, i.e., ciprofloxacin (CPX), sulfamethoxazole (SMX), ibuprofen (IBU), and diclofenac (DCF), onto sugarcane bagasse. The maximum experimental adsorption capacities of single components CPX, DCF, IBU, and SMX, [...] Read more.
This work examines the adsorption in single- and multi-solute adsorption experiments of antibiotic and non-steroidal anti-inflammatory drugs, i.e., ciprofloxacin (CPX), sulfamethoxazole (SMX), ibuprofen (IBU), and diclofenac (DCF), onto sugarcane bagasse. The maximum experimental adsorption capacities of single components CPX, DCF, IBU, and SMX, were 0.98, 0.77, 0.61, and 0.51 mg/g, respectively, with decreases between 5 and 28% in multi-solute mixtures, assuming competitive adsorption. The experimental data of a single drug fitted a pseudo-second-order model, while the experimental isotherms fit the Freundlich model. The presence of CPX did not interfere with the adsorption of other solutes. The adsorption of SMX was lower in the presence of adsorption competitors than SMX single solution. The adsorption of binary systems adequately fitted the Sheindorf–Rebhun–Sheintuch model. The results showed that the competition process depends on each adsorbate and that sugarcane bagasse can adsorb drugs in multi-component systems. Full article
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15 pages, 2034 KiB  
Article
Praseodymium(III) Removal from Aqueous Solutions Using Living and Non-Living Arthrospira platensis Biomass
by Nikita Yushin, Inga Zinicovscaia, Liliana Cepoi, Tatiana Chiriac, Ludmila Rudi and Dmitrii Grozdov
Water 2023, 15(11), 2064; https://doi.org/10.3390/w15112064 - 29 May 2023
Cited by 1 | Viewed by 1343
Abstract
Praseodymium, the sixth-most abundant rare-earth element, is widely used in the aircraft industry for the elaboration of refractory substances, coloring materials, lighting equipment, and fiber optical cables. Living and non-living Arthrospira platensis biomass was applied for Pr(III) removal from aqueous solutions. In bioaccumulation [...] Read more.
Praseodymium, the sixth-most abundant rare-earth element, is widely used in the aircraft industry for the elaboration of refractory substances, coloring materials, lighting equipment, and fiber optical cables. Living and non-living Arthrospira platensis biomass was applied for Pr(III) removal from aqueous solutions. In bioaccumulation experiments, the effect of Pr(III), introduced into the medium in a concentration range of 10–30 mg/L, on biomass productivity, biochemical composition, and antioxidant activity was assessed. The biomass showed high accumulation capacity (more than 99%) toward Pr(III). Supplementation of the cultivation medium with Pr(III) led to a decrease in carbohydrate and lipid content, but it did not significantly influence biomass productivity or the content of proteins and pigments. In experiments with non-living biomass, the effect of pH, Pr(III) concentration, temperature, and contact time on the efficiency of metal removal was investigated. The maximum uptake of Pr(III) was achieved at pH 3.0 after 3.0 min of interaction. The equilibrium data were explained using the Langmuir and Freundlich models, while the kinetics of the process was described by applying pseudo-first-order, pseudo-second-order, and Elovich models. The maximum sorption capacity of Arthrospira platensis biomass calculated from the Langmuir model was 99.3 mg/g. According to the thermodynamic calculations, the process of Pr(III) removal was spontaneous and exothermic in nature. The obtained data can be used for the development of environmentally-friendly technology for Pr(III) recovery from wastewater as well as to understand the effect of Pr(III) on aquatic organisms. Full article
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13 pages, 4554 KiB  
Article
Ciprofloxacin Removal Using Pillared Clays
by Lourdes Jara-Cobos, María Eulalia Peñafiel, Carolina Montero, Miguel Menendez and Veronica Pinos-Vélez
Water 2023, 15(11), 2056; https://doi.org/10.3390/w15112056 - 29 May 2023
Cited by 2 | Viewed by 1347
Abstract
In this work, Ti-pillared bentonites were evaluated to remove ciprofloxacin (CIP) from the aqueous solution. Pillared sodium bentonite (BSP) and pillared calcium bentonite (BCP) were prepared by means of the sol–gel method using titanium tetraisopropoxide with calcination for 3 h at 500 °C. [...] Read more.
In this work, Ti-pillared bentonites were evaluated to remove ciprofloxacin (CIP) from the aqueous solution. Pillared sodium bentonite (BSP) and pillared calcium bentonite (BCP) were prepared by means of the sol–gel method using titanium tetraisopropoxide with calcination for 3 h at 500 °C. They were characterized using the BET method for N2 adsorption, and subjected to X-ray diffraction and Fourier transform infrared spectroscopy. The results show that the surface area of the pillared bentonites increased after the process, more than the natural ones. Pillared sodium bentonite has a more porous structure, larger surface areas, and higher adsorption capacity than pillared calcium bentonite. The kinetic adsorption of ciprofloxacin (CIP) onto pillared bentonites is well described by the pseudo second-order kinetic model. The BSP isotherm well fitted the Freundlich model, while the BCP isotherm fits the BET model better, suggesting multilayer adsorption. DR model shows mostly physical adsorption for CIP on the two adsorbents. The pH influence study indicated that CIP is adsorbed at pH between 6 and 8, which facilitates the use of BCP and BSP in wastewater treatment, whose pH generally oscillates between these ranges. Full article
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19 pages, 10895 KiB  
Article
Adsorptive Removal of Reactive Yellow 145 Dye from Textile Industry Effluent Using Teff Straw Activated Carbon: Optimization Using Central Composite Design
by Melkamu Kifetew, Esayas Alemayehu, Jemal Fito, Zemene Worku, Sundramurthy Venkatesa Prabhu and Bernd Lennartz
Water 2023, 15(7), 1281; https://doi.org/10.3390/w15071281 - 24 Mar 2023
Cited by 7 | Viewed by 1750
Abstract
This study aimed to optimize the preparation condition of activated carbon using Teff straw as a precursor material via evaluating its potential in terms of maximizing the adsorptive removal of Reactive Yellow 145 dye (RY 145) from aqueous solutions. Selective factors, such as [...] Read more.
This study aimed to optimize the preparation condition of activated carbon using Teff straw as a precursor material via evaluating its potential in terms of maximizing the adsorptive removal of Reactive Yellow 145 dye (RY 145) from aqueous solutions. Selective factors, such as activation time, activation temperature, and impregnation ratio on the preparation of Teff Straw-based Activated Carbon (TSAC) were optimized using response surface methodology (RSM). A quadratic regression model with estimated coefficients was developed by RSM and it was observed that model predictions were matched with experimental value with an acceptable R2 value (0.98). Further, the TSAC prepared at optimal condition was characterized using Fourier-transform infrared (FTIR), Scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. The TSAC prepared at optimal condition showed anionic nature with a BET surface area of 627.7 m2/g. In addition, important adsorptive parameters (contact time, solution pH, adsorbent dose, and dye concentration) were evaluated through batch experiments. In such a way, it was determined that 2 h for activation time, 539 °C for activation temperature, and impregnation ratio of 5 g of phosphoric acid per 1 g of TSAC were optimal for efficient adsorption with maximum removal of 98.53% for RY 145 dye. In addition, the TSAC was subjected to test in order to determine its adsorptive performance by treating real textile industry effluent for examining its Chemical Oxygen Demand (COD) removal potential. The results showed that 76% COD was removed from the real textile effluent, which met Ethiopian Environmental Protection Authority (EPA) standard. The finding of this paper asserts that this material is a good and low-cost bio-sorbent that can be used for the removal of pollutants from textile wastewater. Nevertheless, additional investigations of the adsorbents including regeneration options are advisable to draw explicit conclusions. Full article
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15 pages, 3025 KiB  
Article
Adsorption of Atrazine from Synthetic Contaminated Water Using a Packed-Bed Column with a Low-Cost Adsorbent (Moringa oleifera Lam.)
by Rosângela Bergamasco, Daniel Mantovani, Alexandre Diório, Charleston de Oliveira Bezerra, Heloise Beatriz Quesada, Gessica Wernke, Márcia Regina Fagundes-Klen and Luís Fernando Cusioli
Water 2023, 15(7), 1260; https://doi.org/10.3390/w15071260 - 23 Mar 2023
Cited by 2 | Viewed by 1606
Abstract
Atrazine (ATZ) is an herbicide used for increased food production due to its weed and pesticide control capacity in different crops. However, ATZ is a chemical compound that is harmful to the environment and human health, and, unfortunately, it has been detected in [...] Read more.
Atrazine (ATZ) is an herbicide used for increased food production due to its weed and pesticide control capacity in different crops. However, ATZ is a chemical compound that is harmful to the environment and human health, and, unfortunately, it has been detected in surface and groundwater. Therefore, the aim of this paper was to perform the adsorption of Atrazine from a synthetically contaminated water sample using a packed-bed column with a low-cost adsorbent prepared from Moringa oleifera Lam. seeds. The synthesized adsorbent presented an increase in the surface specific area (SBET) of 37% in comparison with the in natura material. The effects of the peristaltic pump flow rate (Q), concentration of the ATZ inlet ([ATZ]inlet) solution, and bed height (H) were studied, with the highest percentage of ATZ removed through the adsorption column (50, 0%) obtained with a packed-bed column with H = 13 cm bed height, Q = 1 mL/min, [ATZ]inlet = 2.0 mg/L, pH = 5.0, a breakthrough time of 25 min, and a saturation time of 420 min. The logistic model was used to best fit the experimental data with an R2 > 0.99, and the Bohart–Adams, Thomas, and Yoon–Nelson models were used to explain and analyze the obtained effects in the continuous adsorption of ATZ. Therefore, the Moringa oleifera Lam. seeds provided a low-cost adsorbent for the continuous adsorption of the herbicide Atrazine in a packed-bed column. Full article
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21 pages, 6126 KiB  
Article
Decolourisation of Real Industrial and Synthetic Textile Dye Wastewater Using Activated Dolomite
by Afnan Ahmadi Zahuri, Muhamad Fazly Abdul Patah, Yusniza Kamarulzaman, Nor Hazlina Hashim, Thinaranjeney Thirumoorthi, Wan Hanna Melini Wan Mohtar, Zarimah Mohd Hanafiah, Zulhelmi Amir and Wan Abd Al Qadr Imad Wan-Mohtar
Water 2023, 15(6), 1172; https://doi.org/10.3390/w15061172 - 17 Mar 2023
Cited by 3 | Viewed by 2263
Abstract
Textile effluent accounts for 22% of the total industrial wastewater produced in Malaysia. Due to their ubiquitous use in organic dyes, inefficiently treated textile wastewaters pose environmental and health hazards. Colour, chemical oxygen demand, biochemical oxygen demand, toxic metals and microbes are the [...] Read more.
Textile effluent accounts for 22% of the total industrial wastewater produced in Malaysia. Due to their ubiquitous use in organic dyes, inefficiently treated textile wastewaters pose environmental and health hazards. Colour, chemical oxygen demand, biochemical oxygen demand, toxic metals and microbes are the commonly targeted water quality parameters in untreated textile fluids. Furthermore, their non-biodegradability and high colour intensity may reduce aquatic diversity by blocking the sunlight. Recently, physical treatment, principally adsorption, has been conducted. Dolomite has additional features, such as performing as a heavy metal and microbe remover. This study employed dolomite for treating textile dye wastewater from a commercial textile manufacturer and synthetic effluent containing methyl orange. Different sizes of dolomite were activated at different temperatures and subsequently added to the water samples in varying amounts. After 2 h of agitation at 100 rpm and sedimentation for 24 h, their absorbance reading was taken. Their morphological, decolourisation percentage, chemical oxygen demand reduction percentage and bacterial growth post-treatment were examined. Despite variances in dolomite’s capacity to decolourise colours, the treatment proved effective in decolourising dyes, removing chemical oxygen demand and reducing bacterial growth. The most significant percentages of decolourisation observed were 98.7% for real textile dye wastewater (RTDW) and 78.0% for synthetic textile dye wastewater (STDW), while for chemical oxygen demand, reductions were 66.7% for RTDW and 73.9% for STDW, respectively. As for microbe growth inhibition, the highest growth reduction percentages were 99.7% and 98.6% for RTDW and STDW, respectively. Full article
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13 pages, 4073 KiB  
Article
Cost-Effective Preparation of Gold Tailing-Based Aerogels for Efficient Adsorption of Copper Ions from Wastewater
by Yingjie Wang, Kaibin Cui, Jiaxuan Bai, Baizeng Fang and Fei Wang
Water 2023, 15(4), 669; https://doi.org/10.3390/w15040669 - 08 Feb 2023
Cited by 5 | Viewed by 1393
Abstract
Water pollution caused by heavy metal ions has attracted worldwide attention. In this work, gold tailings were used as raw materials and the sol–gel method combined with the atmospheric pressure drying method were used to achieve the low-cost preparation of a silica aerogel. [...] Read more.
Water pollution caused by heavy metal ions has attracted worldwide attention. In this work, gold tailings were used as raw materials and the sol–gel method combined with the atmospheric pressure drying method were used to achieve the low-cost preparation of a silica aerogel. (3-Aminopropyl) triethoxysilane (APTES), ethylenediaminetetraacetic acid disodium salt (EDTA-2Na), and chitosan were used to modify the silica aerogel, which was then used as an adsorbent for the adsorption of copper ions in wastewater. The adsorbent type, adsorption time, copper ion concentration, and pH value were investigated as variables to explore the best adsorption conditions. The adsorption mechanism was also elaborated on. The crystal structure, surface morphology, surface functional groups, chemical composition, and specific surface area of the aerogels and the modified aerogels were characterized by various physiochemical characterizations such as XRD, SEM, FT-IR, XRF, and BET. The results showed that the prepared silica aerogel contained 91.1% SiO2, mainly amorphous SiO2, and amino and carboxyl groups. Other functional groups were successfully grafted onto the silica aerogels. The original silica aerogels and modified silica aerogels had a large specific surface area, total pore volume, and pore diameter. When copper ions were adsorbed by the chitosan-modified silica aerogels, the adsorption capacity of the copper ions was the highest (33.51 mg/g) under the conditions of a copper ion concentration of 100 mg/L, a pH value of 7, and an adsorption time of 2 h. The adsorption of Cu2+ was mainly due to the ion exchange and electrostatic gravity. Full article
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16 pages, 1715 KiB  
Article
Zeolite Adsorbents for Selective Removal of Co(II) and Li(I) from Aqueous Solutions
by Eduardo Díez, Cinthya Redondo, José María Gómez, Ruben Miranda and Araceli Rodríguez
Water 2023, 15(2), 270; https://doi.org/10.3390/w15020270 - 09 Jan 2023
Cited by 10 | Viewed by 5055
Abstract
Cobalt and lithium are critical metals because of its shortage, difficulty of extraction and huge economic impact due to their market value. The purpose of this work is to study their selective removal from aqueous solutions in different conditions using two commercial FAU [...] Read more.
Cobalt and lithium are critical metals because of its shortage, difficulty of extraction and huge economic impact due to their market value. The purpose of this work is to study their selective removal from aqueous solutions in different conditions using two commercial FAU zeolites as adsorbent materials. These solids were characterized by XRD, XRF and BET analysis, to follow up of their FAU structure integrity, their Si/Al ratio, and their specific surface area evolutions through their preparation process. The kinetic study indicates that using both zeolites with a dosage of 5 g/L a 100% cobalt removal from aqueous solutions is achievable, while lithium removal is kept around 30% (separation factor of 3.33). This selectivity is important as these two metals frequently appear together in leaching solutions form, for example, ion-Li batteries. In relation to the adsorption equilibrium, cobalt adsorption presents a finite adsorption capacity while this behavior is not observed in lithium adsorption. For this reason, Langmuir model is the most adequate to represent cobalt adsorption, while lithium adsorption is better represented by Freundlich model. Full article
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14 pages, 5338 KiB  
Article
Determination of Pore and Surface Diffusivities from Single Decay Curve in CSBR Based on Parallel Diffusion Model
by Yoshimi Seida, Noriyoshi Sonetaka, Kenneth E. Noll and Eiji Furuya
Water 2022, 14(22), 3629; https://doi.org/10.3390/w14223629 - 11 Nov 2022
Viewed by 1610
Abstract
A novel, simple numerical method to determine the pore and surface diffusivities in adsorbents from a single experimental concentration decay curve obtained using the batch adsorption technique was investigated in this study. The pore and surface diffusion coefficients were determined based on the [...] Read more.
A novel, simple numerical method to determine the pore and surface diffusivities in adsorbents from a single experimental concentration decay curve obtained using the batch adsorption technique was investigated in this study. The pore and surface diffusion coefficients were determined based on the conventional parallel diffusion model in its dimensionless form using a theoretical model correlation. The model assumed that the film mass transfer resistance was negligible, i.e., the condition with a large Biot number, from the single concentration decay curve. The procedure for determining the kinetic parameters was investigated, and the effectiveness of the proposed simple method was validated by comparing the parameters with those reported previously. The single decay curve of p-nitrophenol, obtained by the batch adsorption system using granular activated carbon as an adsorbent, was used for validation. The diffusivities determined by the simple method corresponded fairly well with the diffusivities reported previously. Full article
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25 pages, 5093 KiB  
Article
Sugarcane Bagasse and Orange Peels as Low-Cost Biosorbents for the Removal of Lead Ions from Contaminated Water Samples
by Ntsieni Romani Molaudzi and Abayneh Ataro Ambushe
Water 2022, 14(21), 3395; https://doi.org/10.3390/w14213395 - 26 Oct 2022
Cited by 4 | Viewed by 3057
Abstract
The pollution of water by lead (Pb(II)) constitutes a substantial threat to the environment and subsequently to animals and humans. In this study, the efficacy of sugarcane bagasse (SCB) and orange peels (OPS) have been investigated as potential low-cost biosorbents, individually and in [...] Read more.
The pollution of water by lead (Pb(II)) constitutes a substantial threat to the environment and subsequently to animals and humans. In this study, the efficacy of sugarcane bagasse (SCB) and orange peels (OPS) have been investigated as potential low-cost biosorbents, individually and in a homogeneous combination for the removal of Pb(II) from simulated and real water samples. Biosorbents were characterised using Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) coupled to energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), powder X-ray diffraction (pXRD), a zeta potential analyser, and the Brunauer–Emmett–Teller (BET) method. Batch adsorption studies were explored under several experimental conditions to optimise the removal efficiency of Pb(II) ions from artificially contaminated aqueous solutions. The pH study revealed optimum removal efficiencies of Pb(II) at pH 7, for SCB and OPS. The optimum contact time for SCB and OPS individually and a homogenous mixture was 60, 120, and 120 min, respectively. The study also revealed that the optimum biosorbent dosage was 0.2, 0.17, and 0.2 g for SCB, OPS, and the homogenous combination of SCB and OPS (1:1). Optimum experimental conditions could achieve up to 100% removal efficiencies for 10 and 20 mg/L of Pb(II) using SCB and OPS, respectively. The potential of the homogenised combination of biosorbents demonstrated 100% removal efficiencies for 10 mg/L of Pb(II). The removal of 10 mg/L of Pb(II) in real water samples remained at 100% for biosorbents individually and the homogenised combination. The reusability performance of SCB, OPS, and the homogenised combination of SCB and OPS presented Pb(II) removal efficiencies above 70% for three adsorption–desorption cycles. Full article
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