Modification Of Porous Silica Materials For The Removal Of Organic Dyes

Organic dyes,which are extensively applied in textile industries,raise much concern because they have harmful and toxic effects on human health and ecological systems.Therefore,the removal of dyes is of vital importance before discharge.Many conventional wastewater treatment technologies,such as membrane separation,biochemical oxidation,photodegradation and adsorption,have been used for the removal of dyes to reduce the impact on the environment.Among these techniques,adsorption has been found to be commonly used to remove organic dyes owing to easy operation,low costs and high efficiency.It remains a challenge to develop a low-cost and environmental adsorbent.The objective of this dissertation is to modify porous silica nanomaterials to meet our demands due to their large specific surface area and high resitance.The details are as follows:1.Porous silica nanomaterials have been the topic of interest for researchers because of their natural advantages of large specific surface area and high resitance.Although silica porous materials have been developed as adsorbents,they just combine with some small organic molecules and noble metal.Therefore,it remains a challenge for industrial application due to the high cost.Manganese oxides have been a hot topic of interst because of their advantages of low cost and natural abundance.The relevant work reported that Mn3O4 was an effective adsorbent for the removal of organic dyes.However,it is not widely applied in the industry due to the low specific surface area and poor dispersion.Inspired by the aforementioned,a novel?low-cost and effective adsorbent was synthesized to improve the adsorption ability.In this paper,we reported the synthesis of Mn3O4 nanoparticles coated in the silica porous materials by a mild and simple method.Results indicated that the maximum adsorption capacity was 746 mg/g and the adsorption equlibrium could be reached within 120 min.Moreover,compared with pure Mn3O4 nanoparticles and porous silica,the adsorption capacity has been improved significantly.2.Silicate materials are widely applied owing to their low cost and environmentally benign nature.Researchers have reported that magnesium silicate nanomaterials are considered as a highly effective scavenger of organic dyes and heavy metals.Considering its low specific surface area,we prepared low-cost and environmental magnetic magnesium silicates.The synthesized MgSNTs with high specific surface area(588 m2/g),average pore width(7.13 nm)and pore volume(1.05 cm3/g)had high removal efficiency for low concentration methylene blue and high adsorption capacities for high concentration rodamine B.Besides,it could be easily recovered due with the help of ?-Fe2O3 in the inner chamber,which avoids the secondary pollution problems.The excellent adsorption capacity owes to its specific porous structures.