I am Sana Noor PhD scholar at Abdul Wali Khan University Mardan. My research interests are geopolymer, geopolymeric membrane and magnetic geopolymer composites. I am thankful to IM GROUP OF RESEARCHERS for providing me such opportunity. I believe this content will provide you some knowledge about the geopolymeric membrane and its application in wastewater treatment.

Content Number: 01
Author Name: Sana Noor
Author I’d: SBPWNC – A01
Educational Institution: Abdul Wali Khan University, Mardan, Pakistan
Content Title: Geopolymeric membrane and its application in wastewater treatment

An overview on Geopolymeric membrane in waste water treatment

This content address introduction of geopolymer, geopolymeric membrane, synthesis and its application. One of the most significant environmental issues of the twenty-first century is a lack of drinking water, which has been driven by global climate change and population expansion. As a result, wetlands that are naturally occurring are disappearing, billions of people continue to live in nations facing water emergencies, and they lack access to clean water, sanitation, and hygiene. However, it is believed that between 50 and 80 percent of effluent is released untreated. Wastewater is viewed as a dependable alternative water supply and a way to address the water issue in the face of rising demand. Sixty percent of the 2030 Sustainable Development Goals depend on effective water management and wastewater treatment. There are mainly three stages

Separation, biological treatment, and purification of wastewater treatment that can be used constantly. Membrane technology is only the one that can be used as a solution in all three stages. The first stage involves the separation of bacteria, oil, fat, and suspended solids, followed by the purification process using micro membranes and the final stage using ultrafiltration or reverse osmosis membranes.

Membranes can be categorized as either organic or inorganic depending on the materials employed in their production. Each and every membrane has some advantages and disadvantages in terms of performance, stability, and synthesis methods. Geopolymers are inorganic substances that are beginning to be considered as potential inorganic membrane building materials.

Introduction to geopolymer

Geopolymer is an alternate form of the traditional Portland cement, which is more ecofriendly to the environment. It is an inorganic synthetic polymers forming a long network of SiO₄ and AlO₄.  It is estimated that its emit 0.1 to 0.5 billion tons of CO₂ per year to the environment.  

Formation

The process through which geopolymer is formed is known as Geopolymerization, in which alumino- silicate materials are dissolved in an alkali activator solution at room temperature they form a three dimensional network of silico-aluminate.

Role of alkali activator

In geopolymerization alkali activator play an important role. Highest dissolution rate of Si⁺⁴ and Al⁺³ is reported as 10 M NaOH.

 (a) Geopolymer precursor. (b) Geopolymer backbone.

Geopolymer membrane

Geopolymer membrane play significant role in the effectiveness and sustainability of wastewater treatment.

Improved performance Characteristics

Sustainability to the environment

As compared to conventional material, manufacturing of Geopolymer membrane are usually uses low energy and produces fewer carbon emissions. This is consistent with the circular economy’s tenets, which call for recycling waste materials into useful goods.

Porosity and filtration efficiency

Heavy metals and organic pollutants may be effectively filtered out thanks to the porous nature of Geopolymers. Their filtering capacities can be further enhanced by making changes to increase porosity.

Mechanical and chemical stability

The exceptional mechanical strength and chemical resistance of geopolymer membranes are essential for withstanding the severe conditions frequently present in wastewater treatment settings.

Role of GPM in wastewater treatment

Heavy metal removal

Heavy metals from wastewater may be effectively adsorbed by geopolymer membranes, resolving serious environmental issues associated with industrial contamination. They can be used to cleanse polluted water sources because of their capacity to bind metal ions selectively.

Membrane bioreactors

Advanced membrane-based bioreactors are the result of innovations like adding photocatalysts to geopolymer membranes. These systems improve overall treatment efficacy by filtering and degrading contaminants.

Filtration technologies

Numerous filtration technologies, such as microfiltration and ultrafiltration systems, can used geopolymer. Because of their versatility, wastewater treatment technologies can be connected with existing infrastructure, increasing their versatility.

Impact of Pore size of GPM

The effectiveness of geopolymer membranes to filter out impurities is directly impacted by their porosity. Greater permeability, made possible by higher porosity, permits water to flow through while holding onto larger contaminants and suspended particulates. This feature improves the membrane’s ability to remove impurities from water, which is crucial for efficient wastewater treatment.

Adsorption capacity

If membrane is porous it will provide more surface area for absorbing heavy metals and pollutants from wastewater. Researchers reported that porous GPM can meaningfully improve adsorption of different ions like ammonium ion, copper, nickel cadmium etc. due of this characteristic, geopolymer membranes work especially well in applications where harmful complexes need to be removed.

Anti-fouling properties

Geopolymer membrane design and modification may be helpful in reducing fouling, a common issue in membrane technology that eventually results in decreased performance. Researchers can develop membranes that prevent contaminants from building up on their surfaces and maintain greater operational efficiency by maximizing pore size and distribution.

Manufacturing techniques

Gel-casting technique

This technique combines surfactants with a foaming ingredient, like hydrogen peroxide. By maximizing the slurry conditions, the gelcasting technique enables the controlled creation of high-porosity geopolymer foams with pore size ranging from 67% to 86%. In addition to increasing porosity, this method customizes the membranes’ mechanical characteristics, which qualifies them for use in wastewater treatment applications.

Pore-forming technique

This method involves adding chemical foaming agents immediately to the geopolymer mixture. During the curing process, the foaming agents produce gas, which causes pores in the geopolymer matrix. This process has the benefit of creating ultra-macroporous structures, which can greatly enhance wastewater pollutants’ filtration and adsorption capabilities.

Composite forming method

The mechanical strength and porosity of geopolymer membranes can be improved by adding composite materials and pore-forming agents. Producers can attain desired properties suited for particular wastewater treatment requirements by mixing geopolymer matrices with different additives. This entails strengthening adsorption capabilities for heavy metals and organic contaminants as well as resistance to fouling.

Hydrothermal synthesis

This method creates geopolymer materials with increased porosity and surface area by applying high pressure and high temperature. Hydrothermal techniques are useful for adsorption procedures in wastewater treatment because they can create intricate three-dimensional pore networks that enhance mass transfer characteristics.

From Above discussion it is clear that fundamental factor in GPM manufacturing is to maintain the porosity. Porosity enhance efficiency of filtration, adsorption, mechanical stability etc. Researchers are enhancing further these techniques to treat contaminated water sources.

Schematic diagram of geopolymer preparation

Follow Us on

FACEBOOK

INSTAGRAM

YOUTUBE