scholarly journals Cellulose-Based Hydrogels for Wastewater Treatment: A Concise Review

Gels ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 30
Author(s):  
Maimuna Akter ◽  
Maitry Bhattacharjee ◽  
Avik Kumar Dhar ◽  
Fahim Bin Abdur Rahman ◽  
Siddika Haque ◽  
...  

Finding affordable and environment-friendly options to decontaminate wastewater generated with heavy metals and dyes to prevent the depletion of accessible freshwater resources is one of the indispensable challenges of the 21st century. Adsorption is yet to be the most effective and low-cost wastewater treatment method used for the removal of pollutants from wastewater, while naturally derived adsorbent materials have garnered tremendous attention. One promising example of such adsorbents is hydrogels (HGs), which constitute a three-dimensional polymeric network of hydrophilic groups that is highly capable of adsorbing a large quantity of metal ions and dyes from wastewater. Although HGs can also be prepared from synthetic polymers, natural polymers have improved environmental benignity. Recently, cellulose-based hydrogels (CBHs) have been extensively studied owing to their high abundance, biodegradability, non-toxicity, and excellent adsorption capacity. This review emphasizes different CBH adsorbents in the context of dyes and heavy metals removal from wastewater following diverse synthesis techniques and adsorption mechanisms. This study also summarizes various process parameters necessary to optimize adsorption capacity followed by future research directions.

2020 ◽  
Vol 69 (2) ◽  
pp. 99-112 ◽  
Author(s):  
Hayder A. Alalwan ◽  
Mohammed A. Kadhom ◽  
Alaa H. Alminshid

Abstract The use of agricultural waste to remove heavy metals from wastewater has attracted much attention due to its economic advantages and high removal efficiency which is attributed to different functional groups. The sorption mechanism of biomass can consist of several steps including chemisorption, complexation, adsorption on surface, diffusion through pores, and ion exchange. Heavy metals were removed in different rates depending on the adsorbent and metal itself. For instance, coconut waste showed adsorption capacities of 263 and 285 mg/g in removing lead and cadmium ions, respectively. Also, black oak bark has adsorbed mercury in an adsorption capacity of 400 mg/g, while wheat brans adsorption capacity for chromium was 310 mg/g. The adsorption capacity is commonly calculated by Lagergren's first-order equation, the Redlich Peterson model, and the Brunauer–Emmett–Teller (BET) model. However, Langmuir and Freundlich models were intensively used to calculate the adsorbed amount by a unit weight of solid sorbents. This review article aims to present the recently available information on utilizing the biomass materials for heavy metals removal. Here, we highlight the increasing use of these materials due to their low cost, regeneration ability, high adsorption efficiency, and small chemical or biological sludge with a possibility of metal recovery.


Author(s):  
Dr. Kavita Gour ◽  

In the Present investigation various activated carbon derived from waste material of plant has been synthesized .These carbon materials have high porosity .This high degree of porosity of adsorbents is associated with large surface area, which makes it an excellent adsorbent for removal of Heavy Metals. The activated carbon has advantages over the other with respect of its adsorption capacity, operating Characteristic &Cost. The activated carbon materials have been characterized by surface area, particle size, bulk density, Volatile matter, Moisture content, Ash content, FTIR &SEM studies. The goal of the present investigation was an attempt to develop low cost, highly effective and simple to use activated carbon materials for removal Cr(VI), Cd(II) and Zn(II) from contaminated water based on adsorption phenomenon. This newly developed adsorbent has been proved to be more promising for heavy metals removal without affecting the quality of treated water.


Coagulation is a kind of efficient water treatment method commonly used in domestic anhydrous and industrial wastewater treatment. Inorganic polymer coagulants (polyvalent metal salts) are widely used because of their low cost and ease of use. However, due to the low flocculation effectiveness and the presence of residual metal concentrations in the treated water, their application is limited. Organic synthetic flocculant has been widely used due to its higher flocculation efficiency at lower dosage. However, it has limitations in applicability due to its molecular structure which is less biodegradable and less disperse in water. Therefore, flocculants based on natural polymers have attracted extensive attention from researchers due to their advantages such as biodegradability and environmental friendliness. This paper summarizes the overview of the development of various types of flocculants that were used for industrial wastewater treatment. In addition, the characteristics and application of flocculant is reviewed with their behavior.


Coagulation is a kind of efficient water treatment method commonly used in domestic anhydrous and industrial wastewater treatment. Inorganic polymer coagulants (polyvalent metal salts) are widely used because of their low cost and ease of use. However, due to the low flocculation effectiveness and the presence of residual metal concentrations in the treated water, their application is limited. Organic synthetic flocculant has been widely used due to its higher flocculation efficiency at lower dosage. However, it has limitations in applicability due to its molecular structure which is less biodegradable and less disperse in water. Therefore, flocculants based on natural polymers have attracted extensive attention from researchers due to their advantages such as biodegradability and environmental friendliness. This paper summarizes the overview of the development of various types of flocculants that were used for industrial wastewater treatment. In addition, the characteristics and application of flocculant is reviewed with their behavior.


Author(s):  
Victor Odhiambo Shikuku ◽  
Tome Sylvain

Geopolymers are amorphous aluminosilicates with some varied applications. However, the use of geopolymers in water treatment is a relatively new subject. This chapter discusses developments in synthesis, properties and applications of geopolymers and their composites for removal of heavy metals and dyes from water including reduction of hardness in water. The adsorption mechanisms and effects of various environmental conditions on adsorption efficiency are also highlighted. The chapter demonstrates that geopolymers are low cost and environmentally benign materials for wastewater treatment and offers opportunities as alternative adsorbents for sequestration of various pollutants from water subject to further investigations.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Kashir Ali ◽  
Muhammad Ussama Javaid ◽  
Zaman Ali ◽  
Muhammad Junaid Zaghum

Wastewater has a high concentration of dyes and heavy metals, which are the two most significant contaminants. Due to their high toxicity and vulnerability, they possess a potential threat to human health as well as the ecosystem. There are many ways to eliminate these pollutants from water but adsorption has attained much interest because of its low cost, easy application, and no secondary pollutants. Biomass is considered an ecological burden and a reason for the reduction in the earth’s carrying capacity. These materials may be used as cost-effective adsorbents to remove dyes and heavy metals from wastewater. This paper highlights recent advances made in dye and heavy metal adsorption in the last 10 years. The prime focus of this review paper is on the direct application of these biomasses without any chemical or physical alteration. The removal efficiencies and adsorption capabilities of different biomass-derived adsorbents for the removal of dyes and heavy metals from wastewater are summarised in this study. Additionally, the adsorption mechanisms underlying the removal of dyes and heavy metals using biomass-derived adsorbents have been discussed, with a focus on two kinetic models: pseudofirst-order and pseudosecond-order. Furthermore, the Langmuir and Freundlich isotherms were utilised to verify the experimental findings and to quantify the amount and degree of adsorption favorability. Based on what has been covered in the literature, the conclusion has been drawn. The future research needs are proposed in the area of biomass-derived adsorbent development, their modification for improved efficiencies, and application on large-scale wastewater treatment plants.


2021 ◽  
Vol 1 (1) ◽  
pp. 1-4
Author(s):  
Kavita Gour

In the Present investigation various activated carbon derived from waste material of plant has been synthesized .These carbon materials have high porosity .This high degree of porosity of adsorbents is associated with large surface area, which makes it an excellent adsorbent for removal of Heavy Metals. The activated carbon has advantages over the other with respect of its adsorption capacity, operating Characteristic &Cost. The activated carbon materials have been characterized by surface area, particle size, bulk density, Volatile matter, Moisture content, Ash content,FTIR &SEM studies. The goal of the present investigation was an attempt to develop low cost, highly effective and simple to use activated carbon materials for removal Cr(VI), Cd(II) and Zn(II) from contaminated water based on adsorption phenomenon. This newly developed adsorbent has been proved to be more promising for heavy metals removal without affecting the quality of treated water.


2021 ◽  
Vol 13 (15) ◽  
pp. 8552
Author(s):  
Vahid Alimohammadi ◽  
Mehdi Maghfouri ◽  
Delaram Nourmohammadi ◽  
Pejman Azarsa ◽  
Rishi Gupta ◽  
...  

Clean water is a vital need for all living creatures during their lifespan. However, contaminated stormwater is a major issue around the globe. A wide range of contaminants, including heavy metals, organic and inorganic impurities, has been discovered in stormwater. Some commonly utilized methods, such as biological, physical and chemical procedures, have been considered to overcome these issues. However, these current approaches result in moderate to low contaminant removal efficiencies for certain classes of contaminants. Of late, filtration and adsorption processes have become more featured in permeable concretes (PCs) for the treatment of stormwater. As nanoparticles have vast potential and unique characterizations, such as a higher surface area to cure polluted stormwater, employing them to improve permeable concretes’ capabilities in stormwater treatment systems is an effective way to increase filtration and adsorption mechanisms. The present study reviews the removal rate of different stormwater contaminants such as heavy metals, organic and other pollutants using nanoparticle-improved PC. The application of different kinds of nanomaterials in PC as porous media to investigate their influences on the properties of PC, including the permeability rate, compressive strength, adsorption capacity and mix design of such concrete, was also studied. The findings of this review show that different types of nanomaterials improve the removal efficiency, compressive strength and adsorption capacity and decrease the infiltration rate of PC during the stormwater treatment process. With regard to the lack of comprehensive investigation concerning the use of nanomaterials in PC to treat polluted stormwater runoff, this study reviews 242 published articles on the removal rate of different stormwater contaminants by using PC improved with nanoparticles.


2020 ◽  
Vol 1010 ◽  
pp. 489-494
Author(s):  
Abdul Hafidz Yusoff ◽  
Rosmawani Mohammad ◽  
Mardawani Mohamad ◽  
Ahmad Ziad Sulaiman ◽  
Nurul Akmar Che Zaudin ◽  
...  

Conventional methods to remove heavy metals from polluted water are expensive and not environmentally friendly. Therefore, this study was carried out to investigate the potential of agricultural waste such as pineapple peel (Ananas Cosmos) as low-cost absorbent to remove heavy metals from synthetic polluted water. The results showed that Cd, Cr and Pb were effectively removed by the biosorbent at 12g of pineapple peels in 100 mL solution. The optimum contact time for maximum adsorption was found to be 90 minutes, while the optimum pH for the heavy metal’s adsorption was 9. It was demonstrated that with the increase of adsorbent dosage, the percent of heavy metals removal was also increased due to the increasing adsorption capacity of the adsorbent. In addition, Langmuir model show maximum adsorption capacity of Cd is 1.91 mg/g. As conclusions, our findings show that pineapple peel has potential to remove heavy metal from polluted water.


Author(s):  
Huiru Li ◽  
Shaohua Wu ◽  
Cheng Du ◽  
Yuanyuan Zhong ◽  
Chunping Yang

In recent years, close attention has been paid to microbial flocculants because of their advantages, including safety to humans, environmental friendliness, and acceptable removal performances. In this review, the preparation methods of microbial flocculants were first reviewed. Then, the performances of bioflocculants in the removal of suspended solids, heavy metals, and other organic pollutants from various types of wastewater were described and commented, and the removal mechanisms, including adsorption bridging, charge neutralization, chemical reactions, and charge neutrality, were also discussed. The future research needs on microbial flocculants were also proposed. This review would lead to a better understanding of current status, challenges, and corresponding strategies on microbial flocculants and bioflocculation in wastewater treatment.


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