Hydrogel-based materials as antibacterial agents and super adsorbents for the remediation of emerging pollutants:A comprehensive review

Hydrogels have various potential applications due to their unique characteristics and recently,hydrogels have been utilized as adsorbents in wastewater treatment because of their ability to remove contaminants from water.Constructing strong hydrogels with high adsorption capabilities is crucial for effective wastewater treatment.Scientists and researchers are working to improve the properties of hydrogels by incorporating inorganic elements into polymer networks,which further reduces the costs as well as simplifies their preparation.Natural polymers like starch and alginate are widespread due to their economic and biological advantages,such as biodegradability,biocompatibility,reduced toxicity,environmental friendliness,and low cost.The adsorption of pollutants onto hydrogels as well as their use as antimicrobial agents has garnered significant attention.This review paper summarizes the latest studies on using hydrogels as adsorbents to remove endocrine-disrupting chemicals(EDCs),persistent organic pollutants(POPs),and other emerging pollutants from water environments along with their use as antimicrobial agents.In the first step,different classes of hydrogels and different characterization techniques have been discussed.Next antimicrobial potential of hydrogels is elaborated to understand how these hydrogels can be a potential candidate for such activities.While discussing the adsorption application of hydrogels,different isothermal,kinetics and thermodynamics models have been discussed to highlight the mechanism and nature of forces involved in adsorption of pollutants.Further different simulations such as DFT and MD have been discussed to get more holistic understanding of pollutants adsorption onto hydrogels.A limited number of studies have utilized other techniques such as Monte Carlo simulations and computational fluid dynamics(CFD)so it is important to explore a variety of computational methods to gain a comprehensive understanding of the adsorption process onto hydrogels.

Removal of Reactive Red 198 from aqueous solution by combined method multi-walled carbon nanotubes and zero-valent iron:Equilibrium,kinetics,and thermodynamic

Dyes often include toxic, carcinogenic compounds and are harmful to humans＇ health. Therefore, removal of dyes from textile industw wastewater is essential. The present study aimed to evaluate the efficiency of the combination of zero valent iron （ZVI） powder and multi-walled carbon nanotubes （MWCNTs） in the removal of Reactive Red 198 （RR198） dye from aqueous solution. This applied research was performed in a batch system in the laboratory scale. This study investigated the effect of various factors influencing dye removal, including contact time, pH, adsorbent dose, iron powder dose, initial dye concentration, and temperature. The equilibrium adsorption data were analyzed using three common adsorption models： Langmuir, Freundlich and Temkin. Besides, kinetic and thermodynamic parameters were used to establish the adsorption mechanism. The results showed, in pH = 3, contact time = 100 min, ZVI dose = 5000 mg· L- 1, and MWCNTs dose = 600 mg· L- 1 in 100 mg· L- 1 dye concentration, the adsorption efficiency increased to 99.16%. Also, adsorption kinetics was best described by the pseudo-second-order model. Equilibrium data fitted well with the Freundlich isotherm （R2 = 0.99）. The negative values of AGo and the positive value of △H0 （91.76） indicate that the RR198 adsorption process is spontaneous and endothermic. According to the results, the combination of MWCNTs and ZVI was highly efficient in the removal of azo dyes.

Modelling and optimization of nonylphenol biosorption by novel lowcost magnetic Chlorella vulgaris

Discharging untreated wastewater causes environmental pollution.This research examined the efficiency of removal and the adsorption process of Emerging Contaminant nonylphenol(NP)using magnetic Chlorella vulgaris(M-Chlorella vulgaris).The characterization of M-Chlorella vulgaris involved XRD,FESEM,EDS-Mapping,BET,FTIR,and VSM analyses.The impact of four different parametersdpH,MChlorella vulgaris dose,initial concentration of NP,and contact time on the biosorption process was investigated.To model and optimize the study while minimizing costs and the number of experiments,Response Surface Methodology(RSM)with Central Composite Design(CCD)was employed.According to the findings,the quadratic model with adjusted R^(2)=0.96 was the best fitted among the other models.With pH=3.5,dosage=2.5 g/l,NP concentration=4 mg/l,and reaction time=70 min,which are the optimal parameters,the maximum removal effectiveness was about 91%.The Langmuir model(R^(2)=0.998)and pseudo-second-order model(R^(2)=0.997)exhibited the best fits for the adsorption isotherm and kinetic studies,respectively.The characteristics of M-Chlorella vulgaris were determined to facilitate a spontaneous nature,and thermodynamic experiments indicated that the process of adsorption of nonylphenol is exothermic.The inexpensiveness and availability of adsorbent,suitable efficiency in the biosorption of pollutant and magnetic collection of pollutant from the aquatic environment can be mentioned as the advantages of this process.