Submit to Water Review for Water Propose a Special Issue

Journal Menu

Journal Browser

Coagulants/Flocculants Derived from Natural Materials for Water and Wastewater Treatment

Special Issue Editors
Special Issue Information
Keywords
Published Papers

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

Deadline for manuscript submissions: closed (20 October 2023) | Viewed by 39276

Share This Special Issue

Special Issue Editors

Dr. Sílvia Santos

E-Mail Website
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: adsorption; wastewater treatment; natural adsorbents; toxic metalloids; metal recovery
Special Issues, Collections and Topics in MDPI journals

Dr. Xufei Yang

E-Mail Website
Guest Editor

Department of Agricultural and Biosystems Engineering, South Dakota State University, Brookings, SD 57007, USA
Interests: air quality; livestock environment; environmental engineering; waste management
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Coagulation–flocculation is an operation widely used in water and effluent treatment plants. Although it has been practiced since antiquity, it remains an important method today for removing particles, inorganic and metallic ions, organic matter, and infectious agents. Aluminum and iron salts and organic synthetic polymers are the most commonly used coagulants. Despite their proven efficiency, there is a multitude of reasons that supports the search for alternative coagulants/flocculants. One is the interest for greener water treatment technologies and for bio-based products, minimizing primary mining. Other motivations include the strong influence of pH when using metal-based coagulants, health and toxicity issues due to the residual concentrations of coagulants, and problems related to sludge properties and handling. Coagulants/flocculants derived from renewable resources, such as plant- and animal-derived materials, including industrial and forestry agri-food residues, have attracted scientific attention, and there are already some formulations on the market.

This Special Issue aims to bring together contributions on the current progress in coagulants and flocculants derived from natural products, including, but not limited to, topics, such as preparation and characterization of biocoagulants (extraction, purification, and chemical modification approaches), testing and optimization in different types of water and industrial effluents (dairy, livestock, textile, landfill leachate, etc.), case studies (pilot scale trials and industrial applications), hybrid processes, sludge properties, handling, and recovery. Original research and review articles are welcomed.

Dr. Sílvia Santos
Dr. Xufei Yang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Water is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

coagulation–flocculation
biocoagulants
vegetable extracts
water
wastewater
remediation
sludge

Published Papers (9 papers)

Download All Papers

Order results

Result details

Show export options Show export options

Select all

Export citation of selected articles as:

Research

Jump to: Review

20 pages, 10255 KiB

Open AccessArticle

Application of Chitosan and Its Derivatives as Bioflocculants for Iron and Turbidity Removal from Filter Backwash Water

by Piotr Maćczak, Halina Kaczmarek and Marta Ziegler-Borowska

Water 2023, 15(16), 2913; https://doi.org/10.3390/w15162913 - 12 Aug 2023

Viewed by 1187

Abstract

The present study aimed to investigate the potential application of chitosan (CS) and its two derivatives, dialdehyde chitosan (DCT) and carboxymethyl chitosan (CMC), as new flocculants in the purification of filter backwash water. The main objective of the work was to remove the disadvantages and inconveniences associated with using synthetic flocculants, mainly based on polyacrylamide, by using biodegradable and non-toxic biopolymer flocculants. The chitosan derivatives were obtained in the process of the chemical modification of this polysaccharide. CS was oxidated with periodate in acetic acid solution to obtain DCT with a degree of substitution (DS) of 44.29%. For the CMC synthesis, after the alkaline activation of chitosan, the solution was treated with monochloroacetic acid (MCA) at 60 °C for 3 h, leading to carboxymethylated chitosan formation with a DS of 49.55%. Characterizations of the flocculants using Fourier transform infrared (FT-IR) spectroscopy, ¹³C nuclear magnetic resonance (¹³C NMR) spectroscopy, and an elementary analysis confirmed the successful modification of the chitosan. The morphology and thermal stability of the samples were investigated using scanning electron microscopy (SEM) and a thermogravimetric analysis (TGA), respectively. Moreover, the biopolymer materials were studied in a series of flocculation jar tests for filter backwash water samples collected at a water treatment plant (WTP) in Kutno, Poland. CMC turned out to be a particularly effective agent in an optimal amount of 0.2 mg/L, achieving nearly 99% iron removal and 98.26% turbidity removal efficiency rates, which indicates that chitosan–based materials can be ecological alternatives for polyacrylamide flocculants, effectively removing the impurities of iron ions. Full article

(This article belongs to the Special Issue Coagulants/Flocculants Derived from Natural Materials for Water and Wastewater Treatment)

► Show Figures

Figure 1

14 pages, 2785 KiB

Open AccessArticle

Continuous-Flow Grafting of LENFLOC^™ Coagulant for Water Treatment toward Circular Economy

by Ibrahim Muntaqa Tijjani Usman, Yeek-Chia Ho, Man-Kee Lam, Pau-Loke Show and Wawan Sujarwo

Water 2023, 15(13), 2484; https://doi.org/10.3390/w15132484 - 06 Jul 2023

Cited by 1 | Viewed by 1336

Abstract

This study investigated the efficiency of LENFLOC^™ production using a microwave-assisted continuous-flow grafting process. The study discussed the contribution of plant-based coagulants for water and wastewater treatment toward the circular economy in water treatment. Lentil waste extract was used to produce LENFLOC^™ using (2-methacryloyloxyethyl) trimethyl ammonium chloride with 75 wt.% on H₂O as a chain monomer and cerium ammonium nitrate (≥98%) as an initiator. The continuous flow grafting process was conducted at a constant flowrate of 60 mL/min and reaction time of 30 s. The process was optimised using RSM to obtain optimum conditions of process factors. Characterisation studies were conducted using Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray. A comparison study was performed using a Jar test with LENFLOC^™, lentil waste extract, and a polymer as coagulants. The results obtained show that the continuous-flow grafting process was efficient with an optimum grafting percentage of 330%. The characterisation studies confirmed the grafting process. A 99% turbidity removal rate was achieved with LENFLOC^™ as a coagulant with a lower dosage compared to the lentil waste extract. Furthermore, microscope imaging showed improved floc compaction when using LENFLOC^™ as a coagulant. The continuous-flow grafting process has been shown to be effective; therefore, its potential for upscaling the process is possible. Full article

(This article belongs to the Special Issue Coagulants/Flocculants Derived from Natural Materials for Water and Wastewater Treatment)

► Show Figures

Figure 1

13 pages, 3481 KiB

Open AccessArticle

Preparation of Cationic Cellulose as a Natural Flocculant/Sorbent and Its Application in Three Water Treatment Scenarios

by Noor Haleem, Cheng Zhang, Yousuf Jamal, Karlee Albert, Dongdong Fan, Bin Yao, Fida Hussain and Xufei Yang

Water 2023, 15(11), 2021; https://doi.org/10.3390/w15112021 - 26 May 2023

Cited by 2 | Viewed by 1628

Abstract

In this study, cationic cellulose (CC) was prepared by etherifying commercial cellulose with (3-chloro-2 hydroxypropyl) trimethylammonium chloride (CHPTAC) in an alkaline medium. The prepared CC was characterized using Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and nuclear magnetic resonance (NMR). The characterization results affirmed the successful cationization of cellulose. Upon optimization of reaction conditions, a CC sample with a degree of substitution (DS) of 0.857 was achieved. The CC sample was then tested as a flocculant or sorbent in three environmental applications: algal harvesting, solid removal from dairy wastewater, and capture of methyl orange (MO) in dye wastewater. The effects of dose level and pH on flocculation/sorption performance were studied. Under the optimal dose level and pH conditions, up to 90.4% of dry algal biomass and 53.3% of suspended solids in the dairy wastewater were removed, as measured by standard jar testing. Around 64.2% of MO in the synthetic wastewater was sorbed on the prepared CC and removed, as determined by absorbance at 463 nm. The new CC preparation method exempts the pre-dissolution of cellulose in a solvent and is expected to promote the application of CC in water treatment and the alike scenarios. Full article

(This article belongs to the Special Issue Coagulants/Flocculants Derived from Natural Materials for Water and Wastewater Treatment)

► Show Figures

Figure 1

14 pages, 1858 KiB

Open AccessArticle

Use of Extracted Proteins from Oak Leaves as Bio-Coagulant for Water and Wastewater Treatment: Optimization by a Fractional Factorial Design

by Abderrezzaq Benalia, Walid Chaibraa, Sara Djeghar, Kerroum Derbal, Amel Khalfaoui, Asma Mahfouf, Raouf Bouchareb, Antonio Panico and Antonio Pizzi

Water 2023, 15(11), 1984; https://doi.org/10.3390/w15111984 - 24 May 2023

Cited by 6 | Viewed by 1592

Abstract

The present work sheds light on the potentiality of proteins extracted from oak (Quercus robur) leaves to treat both drinking water and industrial oily wastewater. The work was structured in three steps: firstly, oak leaves in powder form were analyzed by FTIR, XRD and SEM, thus showing the presence of proteins acting as bio-coagulants; secondly, an experimental design was conducted. According to the design of experiences based on fractional design (2⁸⁻⁴), the highest protein concentration (4.895 mg/g) was obtained for the following operating parameters: no filtration, pH of 12, temperature of 20 °C, stirring speed of 300 rpm, stirring time of 60 min, maceration time of 4 h, centrifugation speed of 400 rpm, centrifugation time of 10 min. Finally, a jar test apparatus was used to study the effects of proteins from oak leaves on the characteristics of both drinking water and industrial oily wastewater. In drinking water, the turbidity was reduced from 15.7 to 4.82 NTU when 0.098 mg/L of oak leaves protein was added, thus satisfying the requirements of the national drinking water standards; whereas, in industrial oily wastewater turbidity, total suspended solids, chemical oxygen demand and organic matter were reduced by 96.87, 89.86, 96.39 and 46.28%, respectively, when 0.538 mg/L of oak leaves protein was added. This study opens new perspectives related to the research and development of organic coagulants applicable to industrial wastewater treatment. Full article

(This article belongs to the Special Issue Coagulants/Flocculants Derived from Natural Materials for Water and Wastewater Treatment)

► Show Figures

Figure 1

15 pages, 2830 KiB

Open AccessArticle

Magnetic Natural Coagulants for Plastic Recycling Industry Wastewater Treatability

by Thais Ribeiro, Fellipe Jhordã Ladeia Janz, Dandley Vizibelli, Julio Cesar Ângelo Borges, Joelmir André Borssoi, Amanda Alcaide Francisco Fukumoto, Rosângela Bergamasco, Natália Ueda Yamaguchi and Edilaine Regina Pereira

Water 2023, 15(7), 1276; https://doi.org/10.3390/w15071276 - 24 Mar 2023

Cited by 3 | Viewed by 1716

Abstract

The plastic recycling industry generates a high volume of wastewaters. In this study, an unprecedented use of Moringa oleifera and tannin (Acacia mearnsii bark) associated with magnetite was proposed for the treatment of these wastewaters. The response surface method (RSM) and central composite rotational design (CCRD) methodology was applied to optimize the influence of operational variables (pH, temperature, electrical conductivity, turbidity, apparent color, chemical oxygen demand (COD), and total solids) on the performance of the magnetic natural coagulants on coagulation, flocculation, and sedimentation process. The results indicated that temperature, pH, electrical conductivity, and total solids did not generate significant differences in treatments when magnetite was added to natural coagulants. Similarly, the parameters apparent color, turbidity, and COD also did not present significant differences in treatments with Moringa oleifera and magnetite association, although achieving high efficiencies. Finally, the addition of magnetite significantly improved tannin efficiency removal for turbidity, apparent color, and COD with the optimized treatment (21.55 mg L⁻¹ of tannin concentration and 28 min of sedimentation). Thus, natural coagulants associated with magnetite are potential alternatives for the treatment of plastic recycling wastewater and could be used as an environmentally friendly coagulant. Full article

(This article belongs to the Special Issue Coagulants/Flocculants Derived from Natural Materials for Water and Wastewater Treatment)

► Show Figures

Figure 1

14 pages, 984 KiB

Open AccessArticle

Microwave-Assisted Extraction of Polyphenols from Eucalyptus Bark—A First Step for a Green Production of Tannin-Based Coagulants

by Isabella T. Tomasi, Sílvia C. R. Santos, Rui A. R. Boaventura and Cidália M. S. Botelho

Water 2023, 15(2), 317; https://doi.org/10.3390/w15020317 - 12 Jan 2023

Cited by 6 | Viewed by 2055

Abstract

Tannins are natural polyphenolic compounds widely found in plants. The production of natural coagulants for water treatment is one of their new applications. Polyphenols extraction is the first step for synthesizing tannin-based coagulants. Eucalyptus globulus bark (EGB), an abundant by-product of the pulp and paper industry, usually applied as fuel for energy production, was used in this work as a tannin source. The extraction of polyphenols from EGB was studied using water as a solvent. Extraction assays employing different extraction techniques were conducted. Microwave-assisted extraction showed superior performance and was further optimized. The influence of irradiation time, water-to-bark ratio, and temperature were evaluated using Response Surface Methodology. The extraction yield and the total phenolic content of the extract were modeled as function of the extraction conditions. The overall best conditions that maximize both responses were obtained through multi-response optimization. Optimized values (15% of extraction yield and a phenolic content of 354 mg of gallic acid equivalents per gram of extract) were predicted for an extraction time of 15 s, a liquid-to-solid ratio of 48.5 mL/g, and 141 °C. The extract generated under these conditions presented a condensed tannin content of 645 mg/g, expressed in terms of catechin equivalents. EGB presented good tannin-extractable contents to produce natural coagulants. Full article

(This article belongs to the Special Issue Coagulants/Flocculants Derived from Natural Materials for Water and Wastewater Treatment)

► Show Figures

Figure 1

14 pages, 2536 KiB

Open AccessArticle

Parametrical Study for the Effective Removal of Mordant Black 11 from Synthetic Solutions: Moringa oleifera Seeds’ Extracts Versus Alum

by Amina Hadadi, Ali Imessaoudene, Jean-Claude Bollinger, Sabrina Cheikh, Aymen Amine Assadi, Abdeltif Amrane, Mohamed Kebir and Lotfi Mouni

Water 2022, 14(24), 4109; https://doi.org/10.3390/w14244109 - 16 Dec 2022

Cited by 13 | Viewed by 2299

Abstract

Prior studies have examined the ability of Moringa oleifera (MO) seed extract, among other natural coagulants, to remove several types of dyes. MO has been proven to have a high capacity to remove some anionic dyes. The aim of the present study is to explore the possible use of aqueous and saline extracts of MO as biocoagulants for the removal of Mordant Black (MB11) from aqueous solution. Their performances were compared to that of aluminum sulfate (alum). To do so, various operating parameters were investigated such as coagulant dose (100–600 mg/L), pH (3–11), initial dye concentration (100–350 mg/L), sodium chloride concentration (0.2–2 M), and sedimentation time (15–90 min). The maximum percentages of MB11 removal were found to be 98.65%, 80.12%, and 95.02% for alum, aqueous extract of MO (MOPW), and saline extract of MO (MOPS), respectively, at around pH 6.5 and for coagulant doses of 400 mg/L (alum) and 500 mg/L (MOPW and MOPS). The coagulation-flocculation mechanism of biocoagulants was hypothesized to be adsorption and charge neutralization. The two biocoagulants (MOPW and MOPS) showed an interesting versatility towards pH counter to alum which was very sensitive to this parameter. pH variations were measured for the three coagulants and proven to be negligible for the biocoagulants. Faster sedimentation time was recorded when MOPW and MOPS were used, suggesting the existence of larger quickly settleable flocs. Considering their high coagulative capacity, rapid and cost-effective preparation, and eco-friendly character, MO extracts can be considered as powerful alternatives to aluminum sulfate in the remediation of MB11 from wastewaters. Full article

(This article belongs to the Special Issue Coagulants/Flocculants Derived from Natural Materials for Water and Wastewater Treatment)

► Show Figures

Figure 1

Review

Jump to: Research

14 pages, 295 KiB

Open AccessReview

Could Plant-Based Flocculants Substitute the Conventional Synthetic Chemicals in the Sludge Dewatering Process?

by Yosra Hadj Mansour, Bouthaina Othmani, Faouzi Ben Rebah, Wissem Mnif, Mongi Saoudi and Moncef Khadhraoui

Water 2023, 15(14), 2602; https://doi.org/10.3390/w15142602 - 18 Jul 2023

Cited by 3 | Viewed by 1460

Abstract

Due its high water content, sewage sludge dewatering is not just a simple operation; rather, it is a challenging process and a costly management task. Its final handling is usually preceded by several dewatering steps, and among them is the conditioning process known as the flocculation stage, which is carried out using synthetic chemical reagents. Despite the abilities of these additives to reduce sludge volume and extract its bound waters, they are suspected to cause serious environmental and health threats. Their substitution by natural and efficient additives originating from plant extracts could thus be a safe and an eco-friendly alternative, overcoming ecosystem damages. It is within this context that the present review paper critically investigates the efficacy and feasibility of plant-based flocculants, aiming to enhance sludge dewatering and dispense with environmental burdens. To do so, the types of the conventional chemical flocculants, their drawbacks, and their impacts on the ecosystem and human health were addressed. In parallel, the potential dewatering efficiency of plant extracts toward sludge treatment was compiled, and their mechanistic dewatering paths performances were thoroughly discussed. The challenges associated with dewatered sludge and its potential exploitation were also highlighted to motivate scientific communities to further explore green resources for sludge processing. It is suggested that green resources such as Moringa, Cactus, Aloe, and Okra could be used as green flocculants instead of chemical ones, which would provide a promising and eco-sustainable approach to sludge dewatering and might represent a path towards an environmentally friendly and clean technology. Full article

(This article belongs to the Special Issue Coagulants/Flocculants Derived from Natural Materials for Water and Wastewater Treatment)

27 pages, 2500 KiB

Open AccessReview

Application of Natural Coagulants in Water Treatment: A Sustainable Alternative to Chemicals

by Bhupendra Koul, Nargis Bhat, Mustapha Abubakar, Meerambika Mishra, Ananta Prasad Arukha and Dhananjay Yadav

Water 2022, 14(22), 3751; https://doi.org/10.3390/w14223751 - 18 Nov 2022

Cited by 38 | Viewed by 24711

Abstract

Water treatment (WT) is currently among the major areas of research due to the depletion of water resources and fearmongering regarding environmental pollution, which has compelled the upgrading of conventional WT technology towards recycling and reuse. This review aims to provide the current state of natural coagulants and their application in the purification of surface water as sufficient clean water is required for household needs, health security, and environmental safety. A thorough and systematic review of the existing literature was performed, and the information related to water treatment using natural coagulants was compiled from 237 articles under various sections using a computerized bibliographic search via PubMed, Scopus, Web of Science, Google Scholar, CAB Abstracts, and several websites. The work provides explicit information related to natural coagulants and their merits and limitations, outlines methods to increase their coagulation performance, and highlights their coagulation mechanism, efficacy, valorization potential, and sustainability. From the information obtained, it can be concluded that although chemical coagulants are efficient in WT, they are usually expensive, toxic, associated with health issues, and thus non-sustainable. A sustainable alternative is the use of natural coagulants, which are readily available, economical, easy to use, biodegradable, non-toxic, eco-friendly, effective, and generate lower sludge volumes. They work via an adsorption process that involves polymeric bridging or neutralization of the charge. The WT efficiency of natural coagulants ranges from 50–500 nephelometric turbidity units (NTUs), which is similar to chemicals. Thus, they can be deployed in WT regimes and can contribute to the health security of rural populations in developing countries. It is unfortunate that, despite the known benefits of natural coagulants, their acceptance, commercialization, and widespread industrial application across the globe are still low. Therefore, there is a need for more exhaustive investigations regarding the mode of action, adoption, and commercialization of natural coagulants as a sustainable alternative to chemicals for a circular economy. Full article

(This article belongs to the Special Issue Coagulants/Flocculants Derived from Natural Materials for Water and Wastewater Treatment)

► Show Figures

Journal Menu

Journal Browser

Coagulants/Flocculants Derived from Natural Materials for Water and Wastewater Treatment

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (9 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI