Details

Autor(en) / Beteiligte

• Sanad, Moustafa M.S.
• Gaber, Seleem E.
• El-Aswar, Eslam Ibrahim
• Farahat, Mohsen M.

Titel

Graphene-magnetite functionalized diatomite for efficient removal of organochlorine pesticides from aquatic environment

Ist Teil von

• Journal of environmental management, 2023-03, Vol.330, p.117145, Article 117145

Ort / Verlag

England: Elsevier Ltd

Erscheinungsjahr

2023

Quelle

MEDLINE

Beschreibungen/Notizen

• A unique composite based on graphene oxide, magnetite, and diatomite was synthetized by eco-friendly dry coating technique for the removal of four toxic organochlorine pesticides from agricultural drainage. The prepared composite was fully characterized using X-ray fluorescence (XRF), X-ray diffraction (XRD), particle size analyzer, Vibrating-sample magnetometer (VSM), magnetic susceptibility meter, zeta potential, scanning electron microscopy-energy dispersive X-ray spectrometer (SEM-EDS), and Brunauer–Emmett–Teller analysis (BET) techniques. The characterization results confirmed the fabrication of a discrete core/shell structured composite possess both adsorptive and magnetic nature. The surface area, pore volume and pore diameter were 23.4 m2/g, 0.0026 cm3/g, and 4.5 nm, respectively. The amenability to use the fabricated composite as an adsorbent for some organochlorine pesticides was investigated under different conditions of concentration, time, pH, and temperature. Batch adsorption experiment showed that 97% removal efficiency was observed for all the studied pesticides with adsorption capacities of 7.78 mg/g after 2 h contact time and at any pH region. The adsorption was exothermic (ΔH < 0), spontaneous (ΔG° < 0), followed pseudo 2nd order kinetics (R2 > 0.998), and fitted well to Langmuir's isotherm pattern for all pesticides (R2 > 0.98). It is assumed that organochlorine pesticides were initially physisorbed by the graphene nanoplatelets via hydrophobic and π-π interactions along with chemisorption for forming monolayer. Moreover, the pesticides molecules could diffuse in the DMG composite micropores and be trapped in the structural defects. The regeneration of the composite exhibited over 90% removal efficiency even after seven cycles. The fabricated composite was examined to remove organochlorine from a real water sample, the obtained results suggest the possibility to use this composite as an economical, effective and sustainable adsorbent for the treatment of pesticides contaminating water. [Display omitted] •A unique natural composite (DMG) was synthesized via dry coating technique.•The adsorption of organochlorine pesticides was an ideal pseudo 2nd order reaction.•Langmuir's isotherm yields better fit than the Temkin and Freundlich models.•The maximum adsorption capacity for four organochlorine pesticides was ≥10 mg/g.•The removal efficiency of DMG composite was ≥85% even after 7th cycle.