TeM	track-etched membrane
PET	polyethylene terephthalate
XRD	X-ray diffraction
Cu/PET	composite membrane synthesized using an “etched-only” template
Cu/Ox_PET	composite membrane synthesized using an oxidized template
MT	microtube
SEM	scanning electron microscopy
XPS	X-ray photoelectron spectroscopy
EDX	energy dispersive X-ray analysis
Qe	amount of As(III) adsorbed by the unit mass of copper (mg/g)
C0	feed As(III) concentration (mg/L)
Ce	concentration of As(III) in aliquots (mg/L)
DC	degree of crystallinity (%)
L	average crystallite size (nm)
${\mathrm{q}}_{\mathrm{t}}$	adsorption capacity at time $\mathrm{t}$ (mg/g)
${\mathrm{k}}_1$	First-order reaction rate constant (min−1)
${\mathrm{k}}_2$	pseudo-second-order rate constant of adsorption ($\frac{\mathrm{g}}{\mathrm{mg}\times \min }$)
$\mathsf{\alpha }$	initial rate of the adsorption process, mg/g × min
$\mathsf{\beta }$	desorption constant (g·mmol−1)
Ra	roughness of the composite (nm)
b	constant related to the energy of adsorption (i.e., Langmuir constant (L/μg))
Ce	equilibrium concentration of adsorbate (mg/L)
${\mathrm{Q}}_0$	maximum monolayer coverage capacity (mg/g)
${\mathrm{k}}_{\mathrm{F}}$	Freundlich isotherm constant related to the adsorption capacity (μg/g)
${\mathrm{Q}}_{\mathrm{d}}$	adsorption capacity of the Dubinin–Radushkevich monolayer (μg/g)
$\mathsf{\beta }$	constant associated with the free energy of sorption (mol2/kJ2)
${\mathrm{E}}_{\mathrm{DR}}$	free energy of adsorption (kJ/mol)