Synthesis of novel adsorbent by intercalation of biopolymer in LDH for the removal of arsenic from synthetic and natural water

This study focuses on the synthesis of nanocomposites named CCA and CZA that were prepared by the incorporation of cellulose(CL)in the Ca/Al and Zn/Al layered double hydroxide(LDH),respectively.These materials were then used for the uptake of As(Ⅲ)and As(V)from aqueous medium.Characterization of both nanocomposites(CCA and CZA)was done using FTIR and Raman analysis to identify the functional groups,N2 adsorption-desorption isotherms to determine the specific surface area and pore geometry and XPS analysis to obtain the surface atomic composition.Some other characters were investigated using simultaneous TGA and DTA and elemental chemical analysis(CHNS/O).The crystallinity of the prepared nanocomposites was displayed by XRD patterns.Furthermore,the sheet-like structure of the LDHs and the irregularity of surface morphology with porous structure were observed by TEM and SEM microphotographs.Optimization of maximum adsorption capacity was adjusted using different parameters including pH,contact time and adsorbent dosage.The pseudo-second-order model was in good fitting with kinetics results.The adsorption isotherm results showed that CZA exhibits better adsorption capacity for As(Ⅲ)than CCA and the Langmuir isotherm model described the data well for both nanocomposites.Thermodynamic studies illustrated the endothermic nature of CCA and exothermic nature on CZA,as well as the fact that the adsorption process is spontaneous.A real water sample collected from well located in Gabes(Tunisia),has also been treated.The obtained experimental results were confirmed that these sorbents are efficient for the treatment of hazardous toxic species such as.

Characterization and physicochemical aspects of novel cellulose-based layered double hydroxide nanocomposite for removal of antimony and fluoride from aqueous solution

A series of novel adsorbents composed of cellulose(CL)with Ca/Al layered double hydroxide(CC_(x)A;where x represent the Ca/Al molar ratio)were prepared for the adsorption of antimony(Sb(V))and fluoride(F^(-))ions from aqueous solutions.The CC_(x)A was characterized by Fourier-transform infrared spectroscopy(FTIR),Brunauer–Emmett–Teller(BET),elemental analysis(CHNS/O),thermogravimetric analysis(TGA-DTA),zeta potential,X-ray photoelectron spectroscopy(XPS)and scanning electron microscopy with energy dispersive Xray spectroscopy(SEM-EDX)analysis.The effects of varying parameters such as dose,pH,contact time,temperature and initial concentration on the adsorption process were investigated.According to the obtained results,the adsorption processes were described by a pseudo-second-order kinetic model.Langmuir adsorption isotherm model provided the best fit for the experimental data and was used to describe isotherm constants.The maximum adsorption capacity was found to be 77.2 and 63.1 mg/g for Sb(V)and F^(-),respectively by CC_(3)A(experimental conditions:pH 5.5,time 60 min,dose 15 mg/10 mL,temperature 298 K).The CC_(3)A nanocomposite was able to reduce the Sb(V)and F^(-)ions concentration in synthetic solution to lower than 6μg/L and 1.5 mg/L,respectively,which are maximum contaminant levels of these elements in drinking water according to WHO guidelines.