Review on the Removal of Metal Ions from Effluents Using Seaweeds, Alginate Derivatives and Other Sorbents

Biosorbents, especially those derived from seaweed (macroscopic algae) and alginate derivatives, exhibit high affinity for many metal ions. Because biosorbents are widely abundant (usually biodegradable) and less expensive than industrial synthetic adsorbents, they hold great potential for the removal of toxic metals from industrial effluents. Various studies have demonstrated the efficiency of living and non-living micro-organisms, such as bacteria, yeasts, moulds, micro-algae, cyanobacteria and biomass from water treatment sewage to remove metals from solution. Several types of organic and inorganic biomass have also been used as sorbent materials. In addition, by-products from the forestry industry, as well as agriculture waste and natural sorbents, have also been studied. This paper reviews and summarizes some key recent developments in these areas and it describes and discusses some specific applications of selected natural sorbents.Les biosorbants, particulièrement ceux préparés à partir des algues macroscopiques et des dérivés d’alginate, démontrent une très bonne capacité d’adsorption des ions métalliques toxiques. Ces biosorbants étant facilement disponibles (biodégradable) et moins coûteux que les adsorbants (industriels) synthétiques, ils présentent un grand potentiel d’utilisation pour l’enlèvement des métaux toxiques des effluents industriels. Les récents développements dans ce domaine ont été revus et font l’objet de la présente synthèse. Des applications spécifiques sont décrites et discutées.Diverses technologies sont disponibles pour enlever les métaux des effluents industriels tels que la précipitation (sous forme d’hydroxydes ou de sulfures), la coprécipitation, l’adsorption, l’extraction par solvant, la cémentation, l’électrodéposition, l’électrocoagulation, l’échange d’ions et les technologies de séparation membranaire. Néanmoins, la plupart de ces techniques présentent des coûts d’exploitation élevés et, dans certains cas, sont limitées en terme de rendement d’élimination des métaux. Dans ce contexte, l’utilisation d’adsorbants naturels (dérivés de matière organique ou inorganique) constitue une alternative intéressante aux produits synthétiques. De nombreux articles ont d’ailleurs été publiés au cours des dernières années faisant état de la performance d’une grande variété d’adsorbants naturels pour enlever les métaux des effluents.Plusieurs espèces d’algues marines ont aussi démontré des propriétés pour adsorber les métaux, mais les algues marines brunes, telles que Sargassum et Ascophyllum semblent avoir la plus grande capacité de rétention des métaux, à cause de leur grande concentration en polysaccharides. L’intégrité physique des algues est également importante, ceci afin de prévenir leur désintégration pendant les processus d’adsorption. Afin d’améliorer la stabilité et les propriétés mécaniques des algues fraîches, diverses méthodes ont été suggérées : i) greffage dans des polymères synthétiques; ii) incorporation dans des matériaux inorganiques; iii) liaison sur un support adéquat; et iv) séquestration par un agent de liaison.L’acide alginique est un polymère naturel se trouvant dans les algues brunes. Ce polymère est extrait en traitant les algues avec une solution de carbonate de sodium, puis l’acide alginique est précipité, ou converti en sel d’alginate de calcium. Lorsque l’acide alginique réagit avec des ions polyvalents, tel que le calcium, une séquestration se produit procurant un gel d’alginate ayant des forces structurales significatives. L’alginate de calcium peut être préparé sous plusieurs formes, telles que des billes, de la poudre, des membranes, des fibres ou des supports d’immobilisation cellulaire. Les billes sont particulièrement intéressantes du point de vue de leur application et de leur réutilisation.L’utilisation des algues marines en tant que procédé d’enlèvement des métaux doit tenir compte de plusieurs considérations techniques. Les systèmes de biosorption utilisent les biomasses sous forme solide en un procédé conventionnel de contact solide-liquide et, dans certains cas, les systèmes comprennent plusieurs étapes de biosorption et de désorption. L’effluent à traiter peut entrer en contact avec la biomasse selon un procédé en mode discontinu, semi-continu ou continu. Une fois saturés en métaux lourds, les adsorbants peuvent être disposés de façon sécuritaire, ou être réutilisés après élution des métaux. Dans ce cas, la plupart des métaux lourds (Cd, Co, Cu, Mn, Pb, Zn) peuvent être élués à l’aide d’acides dilués (chlorhydrique, sulfurique, nitrique) ou de solutions salines concentrées. Certains métaux qui sont moins dépendants du pH d’adsorption (Au, Ag, Hg) ne peuvent être élués en utilisant un acide dilué. Des solutions de thiourée ou de mercaptol peuvent être utilisées pour l’or et l’acétate de sodium pour la récupération de l’argent. La combustion des algues est également possible, néanmoins, elle n’est envisageable que si l’adsorbant est peu dispendieux et grandement disponible.Plusieurs types de biomasses organiques ou inorganiques peuvent être utilisés comme matériaux adsorbants. Des études ont démontré l’efficacité des microorganismes vivants ou morts incluant les bactéries, les levures, les moisissures, les microalgues, les cyanobactéries et les biomasses issues du traitement des eaux usées (boues d’épuration). Les rejets de l’industrie forestière, incluant les sciures et les écorces de bois riches en lignine et en tannins, ont été également étudiés de façon intensive. Certaines plantes aquatiques (Ceratophyllum demersum, Lemna minor, Myriophyllum spicatum) ont également été évaluées pour leur capacité en phytofiltration et phytoassainissement. D’autres études ont été effectuées sur la performance de fixation des métaux de la chitine, cette dernière étant un biopolymère naturel très abondant, lequel est classé second après la cellulose en terme d’abondance. Ce biopolymère se retrouve largement dans l’exosquelette des crustacés et des coquillages. Le chitosan est produit en effectuant la dé-acétylation de la chitine en milieu alcalin. La mousse de tourbe, les déchets d’agriculture (résidus de thé et de café, pelures de certains légumes, écailles de noix, d’arachides, de cacao) et divers autres adsorbants de nature inorganique (sable, argile, oxyde, zéolites) ont également été étudiés pour la récupération des métaux en solution.D’un point de vue économique, plusieurs méthodes existent pour traiter les eaux usées. La sélection d’une méthode dépend de plusieurs critères, tels que la compatibilité avec les opérations existantes, les coûts d’exploitation, la flexibilité des procédés afin de pouvoir traiter des variations de charges hydrauliques et de concentrations de contaminants. La méthode doit être aussi fiable, robuste et simple d’utilisation. Dans certains cas, des économies substantielles peuvent être réalisées en faisant appel à l’adsorption des métaux sur des biomasses, comparativement aux procédés conventionnels, tel que la précipitation des métaux

Metal Removal by Seaweed Biomass

Environmental metal pollution is a serious public problem, and it has become an issue leading to research in the effluent remediation area. Techniques involving biosorption processes have been found to be promising due to the low cost of nonliving biomaterials, which have the potential to adsorb metal ions from wastewaters. One of the most promising types of biomasses to be used as biosorbents is the seaweed biomass, particularly from brown algae. The biosorption capability of the seaweed biomass relies on their cell wall chemical composition, mainly composed of alginates and fucoidans, molecules with a high presence of functional groups that interact with metal ions. This book chapter focuses on the use of seaweed biomass for metal biosorption and the chemical basis underlying the process. The current state of the commercial status of biosorption technology based on seaweed biomass is presented. Examples of complementary uses of the algae biomass other than industrial wastewater cleaning processes are presented, and the potential reuse of the biomass after the biosorption focused on biofuel production is discussed

Algal biomass as adsorbents for heavy metal sorption from aqueous solutions

This thesis evaluates the performance of marine algal-based biosorbents in treating trace metal bearing aqueous solutions. Native seaweed varieties (Ascophyllum nodosum, Lessonia flavicans, Durvillea potatorum and Laminaria hyperborea) were selected on the basis of their varying algin composition as well as their characteristic mannuronic/guluronic acid content. Dealginated seaweed residues, i.e. waste materials arising during algin extraction from brown marine algae were also evaluated as potential metal biosorbent materials. The biosorbents showed significant metal sorption capacity for copper, cadmium, nickel and zinc from synthetic single metal and multi-metal bearing aqueous solutions. The equilibrium biosorption process may be described using a surface complex formation model. Copper biosorption involved chelation-type surface reactions as well as ion exchange whereas nickel and zinc biosorption may be described by simple ion exchange and electrostatic interactions between metal ions and the negatively charged algal surface. Evidence of stoichiometric release of protons upon metal biosorption has been found. Metal biosorption was found to be dependent upon transport limitations due to intraparticle diffusion. Surface functional groups within algal biosorbents that are responsible for metal-ion binding were identified in an attempt to understand the mechanisms of metal biosorption. Physical and chemical characterization techniques such as potentiometric titrations and esterification were used for surface acidity measurements, nitrogen sorption porosimetry for surface area and pore size distribution analysis and FT-IR spectroscopy to identify carboxyl groups attached to structural polysaccharides in algae. Performance of native and dealginate algal fixed-bed mini-columns provided optimum operating conditions for dynamic exchange between metal ions in solution and the algal biomass. Selected biosorbents were successfully employed to treat real industrial metal-plating rinse waters. The most efficient eluants for regeneration of metal-laden biosorbent columns were also identified

Biosorption technology for removal of metallic pollutants-An overview

The main sources of metallic pollutants to the environment are the diffuse sources such as forests and agricultural soils as well as industrial and municipal wastes, which are either discharged directly or transported in to the environment. Various conventional technologies such as chemical precipitation, solvent extraction, ion exchange, membrane separation, electrochemical treatment etc. have been employed to remove metal pollutants from aqueous solution. The exploration of new technologies involves the removal of toxic metals from wastewater with the use of biological adsorption technology. The biosorption is the selective appropriate process for removal of metal ions uptake that may involve the contribution of diffusion, adsorption, chelation, complexation, coordination, or micro-precipitation mechanisms, depending on the specific substrate (biomass). In this overview, the use of the various low cost, easily available and eco-friendly biosorbents used for removal of metallic pollutants from contaminated water and their mechanism are discussed

Uma revisão da aplicação de adsorventes de baixo custo como método alternativo para biossorção de contaminantes presentes na água

Introduction: When using conventional methods to remove contaminants present in water, it generates limitations, such as low efficiency values, and the need for a large operating area added to a high operational cost. As a result, the scientific community has focused its efforts on improving existing removal methods, such as adsorption more focused on the use of biosorbents. These are generally zero-cost waste materials in nature that have a large volume, an example is those generated in agriculture, such as rice husks, peanut husks, cassava husks, and fruit husks, among others. Methodology: This study sought to carry out an extensive review through a broad database, providing biosorbents already produced and used to remove various contaminants. For certain contaminants such as dyes and some heavy metals, dead or live biomasses present promising removal results. The great advantage is that these materials generally present insufficient management, causing several environmental problems. Once used as biosorbents, they solve the problem of bioaccumulation and support the treatment of effluents, making the process sustainable. Results: The most satisfactory results were obtained in the removal of heavy metals, while the use of microbial biomass presented a lower performance, being more dependent on the control of nutrients and other parameters involving the process. The removal of other organic compounds presented greater complexity since they presented functional groups of varying ionic nature, which influence the interaction have the functional groups present on the surface of the biosorbent. Conclusions: Finally, Biosorption presents several advantages such as its cost-benefit, high effectiveness, easy implementation, and how fibrous residues are used, the active sites are freer to adsorb substances and chemicals. Added to this, it enables the use of waste which supports management, reducing environmental pollution resulting from incorrect disposal, making the process sustainable globally.Introducción: El uso de métodos convencionales para eliminar contaminantes presentes en el agua genera limitaciones, como bajos valores de eficiencia y la necesidad de una gran área operativa sumado a un alto costo operativo. Como resultado, la comunidad científica ha centrado sus esfuerzos en mejorar los métodos de eliminación existentes, como la adsorción más centrada en el uso de biosorbentes. Generalmente se trata de materiales de desecho de costo cero en la naturaleza que tienen un gran volumen, un ejemplo son los generados en la agricultura, como cascarilla de arroz, cascarilla de maní, cascarilla de yuca, cascarilla de frutas, entre otros. Metodología: Este estudio buscó realizar una revisión extensa a través de una amplia base de datos, proporcionando biosorbentes ya producidos y utilizados para eliminar diversos contaminantes. Para ciertos contaminantes como los tintes y algunos metales pesados, las biomasas vivas o muertas presentan resultados de eliminación prometedores. La gran ventaja es que estos materiales generalmente presentan un manejo insuficiente, provocando varios problemas ambientales. Una vez utilizados como biosorbentes, resuelven el problema de la bioacumulación y apoyan el tratamiento de efluentes, haciendo que el proceso sea sostenible. Resultados: Los resultados más satisfactorios se obtuvieron en la eliminación de metales pesados, mientras que el uso de biomasa microbiana presentó un menor rendimiento, siendo más dependiente del control de nutrientes y otros parámetros que involucran el proceso. La eliminación de otros compuestos orgánicos presentó mayor complejidad ya que presentaban grupos funcionales de diversa naturaleza iónica, los cuales influyen en la interacción que tienen los grupos funcionales presentes en la superficie del biosorbente. Conclusiones: Finalmente, la Biosorción presenta varias ventajas como su costo-beneficio, alta efectividad, fácil implementación y como al aprovechar los residuos fibrosos los sitios activos quedan más libres para adsorber sustancias y químicos. Sumado a esto, permite el aprovechamiento de residuos que apoyan la gestión, reduciendo la contaminación ambiental resultante de una eliminación incorrecta, haciendo que el proceso sea sustentable a nivel global.Introdução: Ao utilizar métodos convencionais para remoção de contaminantes presentes na água, gera limitações, como baixos valores de eficiência, e a necessidade de uma grande área operacional somada a um alto custo operacional. Como resultado, a comunidade científica tem concentrado seus esforços no aprimoramento dos métodos de remoção existentes, como a adsorção mais voltada ao uso de biossorventes. Geralmente são resíduos de custo zero na natureza e que possuem grande volume, um exemplo são os gerados na agricultura, como casca de arroz, casca de amendoim, casca de mandioca, casca de frutas, entre outros. Metodologia: Este estudo buscou realizar uma extensa revisão através de um amplo banco de dados, disponibilizando biossorventes já produzidos e utilizados para remoção de diversos contaminantes. Para certos contaminantes como corantes e alguns metais pesados, biomassas mortas ou vivas apresentam resultados de remoção promissores. A grande vantagem é que esses materiais geralmente apresentam manejo insuficiente, causando diversos problemas ambientais. Uma vez utilizados como biossorventes, resolvem o problema da bioacumulação e auxiliam no tratamento de efluentes, tornando o processo sustentável. Resultados: Os resultados mais satisfatórios foram obtidos na remoção de metais pesados, enquanto o uso de biomassa microbiana apresentou desempenho inferior, sendo mais dependente do controle de nutrientes e de outros parâmetros que envolvem o processo. A remoção de outros compostos orgânicos apresentou maior complexidade por apresentarem grupos funcionais de natureza iônica variada, que influenciam na interação com os grupos funcionais presentes na superfície do biossorvente. Conclusões: Por fim, a Biossorção apresenta diversas vantagens como custo-benefício, alta efetividade, fácil implementação, e como são aproveitados os resíduos fibrosos, os sítios ativos ficam mais livres para adsorver substâncias e produtos químicos. Somado a isso, possibilita o aproveitamento de resíduos que dá suporte à gestão, reduzindo a poluição ambiental decorrente do descarte incorreto, tornando o processo sustentável globalmente

Water hyacinth as a biosorbent: A review

Water hyacinth (Eichhornia crassipes), has attracted significant attention as the world’s worst invasive aquatic plant due to its extremely rapid proliferation and congest growth, presenting serious challenges in navigation, irrigation, and power generation. Attempts to control the weed have proved to be costly with minimum results. However, the same plant has demonstrated an amazing ability to absorb and concentrate many toxic metals from aquatic environments. Consequently, research activity on utilization of the plant has been registered over the last few decades. This article reviews literature related to the utilization of E. crassipes in the biosorption and recovery of metals from aquatic environments. Availability in large quantities, high biosorption capacity, renewability and low cost determine the extent to which biosorbents can be adapted technologically. Sorption dynamics through classical and competitive models, effect of physical and chemical treatment, pH, temperature, initial metal concentration and biosorbent dose on metal removal by water hyacinth is discussed.Keywords: Biosorption, heavy metals, precious metals, recovery, water hyacinth

Fixed Bed Column Study for Removal of Chromium (VI) from Aqueous Solution by Using Saw Dust(GMELINA ARBOREA)

The study on performance of low-cost adsorbent such as saw dust of Gmelina arborea (Ghambhari tree) in the removal of Chromium (VI) ion from aqueous solution is performed. The adsorbent material adopted was found to be an efficient media for removal of Chromium (VI)ion in continuous mode using fixed bed column. A comparative study has also been done on the adsorption capacity of saw dust of different mesh sizes. The column studies were conducted with a fixed column of diameter 7cms and a bed height of 50cms. The flow rate of solution passing through the adsorbent bed was maintained at a fixed value of 1litre/min. It was found that the metal uptake capacity (amount of removal) of Chromium (VI) ion decreased but the adsorption capacity (percentage of removal) increased with the decrease in the concentration of chromium (VI) in the initial sample solution. It was also observed that the order of metal uptake capacity & adsorption capacity of saw dust of different ISS mesh size for removal of Chromium (VI) removal was as follows: (-30 +10) > (-50 +30) > (-70 +50)

Application of Biosorption for Removal of Heavy Metals from Wastewater

Fresh water accounts for 3% of water resources on the Earth. Human and industrial activities produce and discharge wastes containing heavy metals into the water resources making them unavailable and threatening human health and the ecosystem. Conventional methods for the removal of metal ions such as chemical precipitation and membrane filtration are extremely expensive when treating large amounts of water, inefficient at low concentrations of metal (incomplete metal removal) and generate large quantities of sludge and other toxic products that require careful disposal. Biosorption and bioaccumulation are ecofriendly alternatives. These alternative methods have advantages over conventional methods. Abundant natural materials like microbial biomass, agro-wastes, and industrial byproducts have been suggested as potential biosorbents for heavy metal removal due to the presence of metal-binding functional groups. Biosorption is influenced by various process parameters such as pH, temperature, initial concentration of the metal ions, biosorbent dose, and speed of agitation. Also, the biomass can be modified by physical and chemical treatment before use. The process can be made economical by regenerating and reusing the biosorbent after removing the heavy metals. Various bioreactors can be used in biosorption for the removal of metal ions from large volumes of water or effluents. The recent developments and the future scope for biosorption as a wastewater treatment option are discussed