## 1 Introduction  
The water contamination resources with heavy metals is a serious problem of environments worldwide. Numerous heavy metals are known to be toxic, dangerous, and non-degradable. Copper is used to manufacture various products, such as metal wires, sheet metals, metal pipes, metal coatings, and fertilizers. It is released into water, where it forms copper compounds or becomes bound to the molecules suspended in the water [1]. Although copper is necessary for human health, it may cause anemia, gastrointestinal damage, and dermatitis if its concentration exceeds the permissible limit. It can also destroy fish and marine plants if it is found in a large amount in sea water [2]. Therefore, copper adsorption from aqueous solutions is of great importance, and to find methods to do this, several technologies have been developed, including adsorption, ion exchange, electrochemical processing, and nanotechnology [3]. Nanotechnology has developed rapidly in various application areas, such as industry, medicine, and water treatment [4].  
Researchers are interested in studying water treatment with the use of chemical, physical, and nanotechnological methods. One example of nanomaterials that have been exploited for this purpose is silver nanoparticles ( AgNPs) [5]. AgNPs are characterized by their anti-bacterial properties and easy separation. Moreover, they possess catalytic activity and a relatively high adsorption capacity and surface area for their small size [6]. In addition to their use in water and air purification, they are used in biomedical applications, food production, cosmetics, household products, and the clothing industry [7].  
Biosynthesis is preferable compared to other methods [8] because it is environmentally friendly, cost effective, and less time-consuming. Biological materials include plant extracts, bacteria, fungi, enzymes, and other substances [9] such as _Ganoderma applanatum_[10], _Staphylococcus aureus_, _Kocuria rhizophila_ and _Bacillus thuringiensis_[11], _Phoma_[12], and _Endophytic fungi_[13]. Plant extracts are considered to be the best biological materials because they are abundant and their chemical compositions facilitates the formation of nanoparticles by functioning as reducing agents that reduce silver ions to the silver element. Plant extracts are also inexpensive and quick to prepare compared to microbes that require sterilization conditions and time to produce them [8], and possess active components that improve the effectiveness of nanoparticles [14; 15], such as extracts of _Artemisia annua_ and _Sida acuta_[16], _Phoenix dactylifera_ fruits [3], _Eriobuty japonica_ (Thunb.) [17], _Acalypha hispida_[18], and _Cassia auriculata_[19].  
_Convolvolulus arensis_ (field bindweed) is a climbing plant that covers wide areas of building frontages, owing to its aesthetic value. Some types of _C. arvensis_ have medicinal uses, whereas others are highly toxic [20].  
This study aimed to synthesize AgNPs from an extract of _C. arvensis_ leaves and to test its effectiveness as an adsorbent material for the treatment of aqueous solutions from dissolved Cu2+ ions. The _C. arvensis_ leaf extract, AgNPs, and Cu2+ were characterized via Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS) and SEM analysis. The adsorption of Cu2+ by the AgNPs was studied through of the effects of the dosage, pH, adsorption isotherm thermodynamic, and kinetic models.