Removal of heavy metals from aqueous solution using platinum nanopartcles/Zeolite-4A

Preparation and application of zeolite-zinc oxide nano composite for nitrate removal from groundwater

Nanomaterial assisted removal of pollutants from water has got great attention. This study aimed to remove nitrate from groundwater using zeolite and zeolite-ZnO nanocomposite as synergetic effect. Zeolite-ZnO nanocomposite was prepared using the co-precipitation method. The Physico-chemical characteristics of the nanomaterials were determined using XRD, SEM, and FTIR. The results revealed that; Zeolite-ZnO nanocomposites with 13.12 nm particle size have successfully been loaded into the zeolite. In addition, its chemical composition was determined using AAS. The removal efficiency of nitrate from groundwater was studied using a batch experiment. The removal of nitrate was investigated as a function of adsorbent dose, pH, initial concentration of nitrate, contact time, and agitation speed. Moreover, the adsorption isotherm and kinetics were also determined. The results showed that the removal of nitrate was 92% at an optimum dose of 0.5 g, pH 5, initial nitrate concentration of 50 mg/L, the contact time of 1 h, and agitation speed of 160 rpm. The removal nitrate has been fitted well by the Langmuir isotherm model with correlation coefficients of R² = 0.988. Thus, indicating the applicability of monolayer coverage of the nitrate ion on the surface of the nanocomposite. The adsorption process follows the pseudo-second-order model with a correlation coefficient of R² = 0.997. The results of this work might find application in remediation of water by removing nitrate to meet the standards of water quality.

A Review on Graphene (GN) and Graphene Oxide (GO) Based Biodegradable Polymer Composites and Their Usage as Selective Adsorbents for Heavy Metals in Water

Water pollution due to heavy metal ions has become a persistent and increasing problem globally. To combat this, carbonaceous materials have been explored as possible adsorbents of these metal ions from solution. The problem with using these materials on their own is that their lifespan and, therefore, usability is reduced. Hence the need to mask them and an interest in using polymers to do so is picked. This introduces an improvement into other properties as well and opens the way for more applications. This work gives a detailed review of the major carbonaceous materials, graphene and graphene oxide, outlining their origin as well as morphological studies. It also outlines the findings on their effectiveness in removing heavy metal ions from water, as well as their water absorption properties. The section further reports on graphene/polymer and graphene oxide/polymer composites previously studied and their morphological as well as thermal properties. Then the work done in the absorption and adsorption capabilities of these composites is explored, thereby contrasting the two materials. This enables us to choose the optimal material for the desired outcome of advancing further in the utilization of carbonaceous material-based polymer composites to remove heavy metal ions from water.

Dye removal from water and wastewater by nanosized metal oxides - modified activated carbon: a review on recent researches

The conventional water and wastewater treatment methods are unable to provide up-to-data organized standards for drinking water and discharging effluents into natural ecosystems. Therefore, developing advanced and cost-effective methods to achieve published standards for water and wastewater and population needs are nowadays necessity. The important parts of this article are providing literature information about dyes and their effects on the environment and human health, adsorption properties and mechanism, adsorbent characteristics, and recent information on various aspects of modified activated carbons with nanosized metal oxides (AC- NMOs) in the removal of dyes. This review also summarized the effect of main environmental and operational parameters such as adsorbent dosage, pH, initial dye concentration, contact time, and temperature on the dye adsorption using AC-NMOs. Furthermore, the applied isotherm and kinetic models have been discussed.

Zeolite-based catalytic micromotors for enhanced biological and chemical water remediation

The novel zeolite-based micromotors showed rapid and safe elimination of bacteria in a very short time and removed heavy metals efficiently.

Synthesis and Characterisation of Nano-Biosorbents and Their Applications for Waste Water Treatment

Nanotechnology is one of the most reliable techniques for the remediation of heavy metals. As nanoparticles have a higher surface area to volume, ratio, and high surface energies, so nano-based absorbents are very efficient. Adsorption technique is the most preferred for the remediation of wastewater pollutants. In the current study, a comparative study was done between bio sorbents, nanosorbents and bio nanosorbents. The chapter studies with the synthesis and characterization of the bio sorbents, bionanosorbents, their mechanism of sorption, their synthesis, in addition, application for the remediation of heavy metals from wastewater. The fly ash is an industrial byproduct. Biosorbents have immense applications in the field of bioremediation of heavy metals. Further, their components have also enhanced removal efficiency from the wastewater.

Calcined Post-Production Waste as Materials Suitable for the Hydrothermal Synthesis of Zeolites

The zeolite production process is currently being very intensively researched. Due to environmental protection, as well as issues related to the guidelines of a zero-waste economy, all activities aimed at obtaining such materials from post-processed waste are extremely important. This article presents an innovative method of utilising calcined carboniferous shale in order to produce synthetic zeolites. The raw material for testing came from two Polish hard coal mines. Both the chemical and phase composition of the coal shale were characterised. Based on the recorded thermal analysis results coupled with the mass spectrometer, the processes occurring during the heating of raw materials were interpreted and the calcination temperatures were determined. The changes in the phase composition of raw materials resulting from the calcination process used were also analysed. The heat-treated raw materials were subjected to the synthesis of zeolites in an aqueous solution of sodium hydroxide by means of the hydrothermal method at a concentration of 2.75 M. The results of water leaching and structural parameters are presented for both raw materials, as well as the produced synthesis. The conducted research confirmed that after the application of the synthetic process on coal shale, a zeolite with a surface area of S_BET equal to 172 m²/g can be obtained.

An investigation on the capability of magnetically separable Fe3O4/mordenite zeolite for refinery oily wastewater purification

Damage to the water resources and environment as a consequence of oil production and use of fossil fuels, has increased the need for applying various technologies and developing effective materials to remove contaminates from oily wastewaters resources. One of the challenges for an economic industrial wastewater treatment is separation and reusability of the developed purifying agents. Development of magnetic materials could potentially facilitate easier and more economic separation of purifying agents. Therefore, herein we have synthesised an efficient and easily recyclable Fe₃O₄/mordenite zeolite using a hydrothermal process to investigate its purification capability for wastewater from Kermanshah oil refinery. The synthesised Fe₃O₄/mordenite zeolite was characterised using XRD, FTIR, SEM, EDX, XRF and BET analysis. XRD result showed that the synthesised Fe₃O₄/mordenite zeolite comprised sodium aluminium silicate hydrate phase [01-072-7919, Na₈(Al₆Si₃₀O₇₂)(H₂O)_9.04] and cubic iron oxide phase [04-013-9808, Fe₃O₄]. Response Surface Method (RSM) combined with Central Composite Design (CCD) was used to identify the optimum operation parameters of the pollutant removal process. The effect of pH, contact time and Fe₃O₄/mordenite zeolite amount on the Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD) and Nephelometric Turbidity Unit (NTU) were investigated. It was found that pH was the most significant factor influencing COD and BOD removal but the quantity of Fe₃O₄/mordenite zeolite was the most influential factor on the turbidity removal capacity. The optimum removal process conditions were identified to be pH of 7.81, contact time of 15.8 min and Fe₃O₄/mordenite zeolite amount of 0.52% w/w. The results show that the regenerated Fe₃O₄/mordenite zeolite can be reused for five consecutive cycles in purification of petroleum wastes.

Sustainability criteria for assessing nanotechnology applicability in industrial wastewater treatment: Current status and future outlook

Application of engineered nanomaterials for the treatment of industrial effluents and to deal with recalcitrant pollutants has been noticeably promoted in recent years. Laboratory, pilot and full-scale studies emphasize the potential of this technology to offer promising treatment options to meet the future needs for clean water resources and to comply with stringent environmental regulations. The technology is now in the stage of being transferred to the real applications. Therefore, the assessment of its performance according to sustainability criteria and their incorporation into the decision-making process is a key task to ensure that long term benefits are achieved from the nano-treatment technologies. In this study, the importance of sustainability criteria for the conventional and novel technologies for the treatment of industrial effluents was determined in a general approach assisted by a fuzzy-Delphi method. The criteria were categorized in technical, economic, environmental and social branches and the current situation of the nanotechnology regarding the criteria was critically discussed. The results indicate that the efficiency and safety are the most important parameters to make sustainable choices for the treatment of industrial effluents. Also, in addition to the need for scaling-up the nanotechnology in various stages, the study on their environmental footprint must continue in deeper scales under expected environmental conditions, in particular the synthesis of engineered nanomaterials and the development of reactors with the ability of recovery and reuse the nanomaterials. This paper will aid to select the most sustainable types of nanomaterials for the real applications and to guide the future studies in this field.

Advanced Nanomaterials for the Removal of Chemical Substances and Microbes From Contaminated and Waste Water

The development of cost-effective, efficient and stable materials helps to provide the affordable solutions to get safe and fresh water to increasing population with health guidelines of emerging contaminants. Nanomaterials (NMs)-based techniques involve the design, synthesis, manipulation, characterization and exploitation of materials for adsorption and separation of target species from the contaminated and waste water. NMs show better adsorption capacity and catalytic for number chemical species and microbes because of their small size and large surface area that favors the purification and treatment of waste or contaminated environmental water. Here, we present the chemical properties, adsorption/removal mechanism and applications of advanced NMs such as magnetic nanoparticles (MNPs), carbon nanotubes (CNTs), graphene and graphene oxide (GO), titanium oxide (TiO2), silica (SiO2), silver (Ag), gold (Au) NPs and zeolites in effective and efficient removal of toxic metal ions, organic and inorganic chemical substances and disease-causing microbes from contaminated and wastewater.