Green Synthesis of Copper Nanoparticles Using Tea Leaves Extract to Remove Ciprofloxacin (CIP) from Aqueous Media

     In the present investigation, the synthesis of copper nanoparticles from green tea was attempted and investigated for its capacity to adsorb drugs (Ciprofloxacin). The copper nanoparticles (Cu-NPs) were characterized by different techniques of analysis such as scanning electron microscopy (SEM) images, atomic force microscope (AFM),  blumenauer-emmer-teller (BET), fourier transform infrared (FTIR) spectroscopy, and zeta potentials techniques. Cu-NPs lie in the mesoporous material category with a diameter in the range of 2-50 nm. The aqueous solution was investigated for the removal of ciprofloxacin (CIP) with green tea-synthesized Cu-NPs. The results showed that ciprofloxacin efficiency depends on initial pH (2.5-10), CIP (2mg/L-15mg / L) dose, temperature (20 ° C-50 ° C); time (0-180 min) and Cu-NP dose (0.1g /L-1g /L). Spherical nanoparticles with an average size of 47nm and a surface area of 1.6562m2/g were synthesized. The batch experiment showed that 92% of CIP 0.01 mg/L were removed at a maximum adsorbent dose of 0.75 g/L, pH 4, 180 min, and an initial 1:1 rate (w / w) of CIP: Cu-NPs. Kinetic adsorption models and ciprofloxacin removal mechanisms were examined. The kinetic analysis showed that adsorption is a physical adsorption system with activation energy of 0.8409 kJ.mol-1. A pseudo-first-order model is preferred for the kinetic removal after the physically diffusing process due to the low activation energy of 13.221kJ.mol-1. On the other hand, Langmuir, Freundlich, Temkin, and Dubinin isotherm models were also studied; the equilibrium data were best fitted with Langmuir and Dubinin isotherm models with maximum adsorption capacity of 5.5279, and 1.1069 mg/g, respectively. The thermodynamic values of ∆G0 were -0.0166, -0.0691, -4.1084, and -0.7014 kJ/mol at 20, 30, 40, and 50 ° C, respectively. The values of ΔH0 and ΔS0 were 18.8603 kJ/mol and 0.0652kJ/mol.k, respectively. These values showed spontaneous and endothermic sorption. The presence of the CIP concentration in aqueous media was identified by UV-analysis.


Introduction
Increasing the risk of health because of indiscriminate drug disposal in aqueous environments and drug contamination of the groundwater system has been a major cause for concern because of harmful environmental effects [1]. Many pharmaceutical industries release toxic contaminants directly or after chemical modifications into the environment [2]. Fluoroquinolones have been usually detected in an aqueous environment within the range of 1-100 mg /L [3]. Ciprofloxacin {(1-Cyclopropyl-6-fluoro-4oxo-7-(piperazine-1-yl)-1, 4-dihydroquinoline-3-carboxylic acid hydrochloride hydrate)} is a commonly used broad-spectrum antibiotic agent of the fluoroquinolone family [3]. Also, the waste from hospitals, housekeepers, and human excretion contributes to drug contamination [1]. The potential presence of antibiotics in water sources is of major concern because of the unknown health consequences from chronically low levels of antibiotics exposure throughout the life of the drinking water, if the antibiotics survive and remain in the drinking water of consumers [3]. These antibiotics have been detected in wastewater in very low levels, but also highly toxic to human, animal, and aquatic life , causing health problems like headache, diarrhea, tremors, nausea, vomiting, etc. Several methods for fluoroquinolone removal have been identified, including photo-catalysis [4], advanced oxidation [5], and adsorption using various adsorbents, for example, carbon activated [6], sawdust [3], agricultural waste, and titanium oxide [7]. However, adsorption has some advantages among these methods because of its high selectivity, high removal efficiency, easy operation, and lower costs [5]. This process uses the so-called "sorbent, adsorbent, or bio-sorbent material," which reduces contaminated solutions in the form of pollutant molecules (so-called adsorbates) [8,9]. To include the adsorbent process in terms of removal efficiency and cost-effectiveness [10,11], care should be taken to choose adsorbents. Nanotechnology can be defined as the physical and biological processes performed for the handling of material to create materials with special properties for use in various applications [12]. Usually, nanotechnology deals with handling low-size materials below 100 nm. Nanomaterials are small products with a broad area of volume that are primarily responsible for the widespread use of nanomaterials in the electronic, mechanical, optical, microbiological, biotechnological, healthcare, environmental, engineering, and many other sectors [13]. Green synthesis is a simple alternative to chemical synthesis, using either bio-organisms or plant extracts. Green synthesis offers advances compared to chemical processes because it makes it easy to extend to Atiya et al.
Iraqi Journal of Science, 2021, Vol. 62, No. 9, pp: 2833-2854 2835 large-scale systems with an environmental, economic, and efficient environment. In green synthesis, typically three major steps are taken: (1) choice of solvent media; (2) choice of eco-friendly reduction agents; and (3) stabilization of nanoparticles with non-toxic substances [14]. Copper nanoparticles were synthesized using plant extract as a reducing agent. Copper nanoparticles have several properties such as low cost, high surface area [15], super-strong structure, antibacterial properties, sensor properties, and catalytic properties [16]. Synthesis of Cu-NPs is cost-effective when compared to that of silver nanoparticle. Due to their surface to volume ratio, copper nanoparticles are highly reactive and easily interact with other particles [17]. The adsorption kinetics was obtained by several models (Pseudo-first order, Pseudo second order, Elovichs [18], and Behnajady-Modirshahla-Ghanbary (BMG)) [19]. The uptake analysis of CIP was studied by applying Langmuir, Freundlich, Temkin, and Dubinin models [18]. The thermodynamic parameters were also studied [20]. The present research is therefore aimed at preparing and distinguishing Cu-NPs. The performance of adsorption of Cu-NPs to the concurrent removal of the antibiotic of ciprofloxacin (CIP) was subsequently studied in detail, taking into consideration the influence of some environmental factors on the adsorption behavior.

Chemicals used
Ciprofloxacin used in this study was provided by the Ministry of Industry (Ibn Sina Centre), and Table-1 shows the characteristics of the drug. The maximum wavelength λ (nm) was measured using a spectrophotometer (UV/VIS model 1800 SHIMADZU). The chemical structure of the drug is shown in Figure-1. Table 1-Main physical and chemical characteristics of Ciprofloxacin (CIP) used in this study [21,22] Drug class Fluoroquinolone IUPAC Name 1-Cyclopropyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-   [21].

Adsorbent Preparation
The Cu-NPs nanoparticles were prepared using a similar procedure described in previous studies [23, 24, and 25] with some modifications.
The extract of the green tea was prepared by weighing 20.0 g of locally available solid green tea in 300 mL of distilled water. The solution was heated for 30 min at 85°C on a hot plate. The extract was filtered using a 0.45 μm membrane filter to remove the suspended tea particles and stored in the refrigerator at 5°C for further use. A solution of 0.10 M CuSO 4 .5H 2 O was prepared by adding 4.996 g of solid CuSO 4 .5H 2 O in 200 mL of distilled water. After complete dissolving, this solution was filtered using a 0.45 μm membrane filter to remove any impurities. The tea extract was mixed with the solution of 0.10 M CuSO 4. 5H 2 O with a proportion of mixing 4:1 w/w by adding it slowly for 15 min at room temperature and constant stirring. After the addition, the color of the solution was changed from blow light to green light, and finally, to a dark yellow, while the formation of dark brown precipitation began after 5 min. This color change indicated the reduction of copper nanoparticles. Following this, 0.1 M NaOH solution was added drop by drop until the pH was adjusted at 9.0 and continuously stirred for 15 min [26]. At pH=9, the dark brown copper nanoparticles were highly precipitated in the beaker and could be collected easily. The brawn precipitate of copper particles was collected by vacuum filtration using filter paper (Whatman No.1) and quickly rinsed several times with distilled water and ethanol to remove any unreacted particles. The Cu-NPs nanoparticles were dried overnight in an oven at 60 °C and then were ground to a fine powder. The green chemical reaction of the reduction of Cu 2+ to Cu 0 may be similar to the reduction of Fe 3+ to Fe 0 [24]. The proposed mechanism can be illustrated in the following reaction: nCu 2+ + 2Ar-(OH) n → nCu 0 + 2nAr₌O + 2nH + where Ar is the phenyl group and n is the oxidized hydroxyl group number by Cu 2+ .

2.3
. Characterization Scanning electron microscopy (SEM) images of Cu-NPs were performed by using SEM TESCAN-Vega3 model. These images were used to detect changes in surface morphology due to adsorbent synthesis or adsorptions. A Shimadzu FTIR spectroscopy instrument (Japan) identified the functional groups in the Cu-NPs and the importance of them in the removal process. These analyzes were conducted in the region of 400-4000 cm -1 of the wavenumber, with the range falling within that of all well-known agriculture adsorption groups. The essential green tea surface area was calculated using the Brunauer -Emmett -Teller (BET) application. The 120 mg Cu-NPs sample was then transmitted onto the BET tube (inner diameter = 0.7 cm) and released in vacuum for 24 hours before BET testing at a temperature of 60 ° C. The zeta potential analysis was used to detect nanoparticle stabilization, which showed that the nanoparticles were more agglomerative with potential negative zeta values. Atomic force microscopy (AFM) was used to measure the dimension and morphology of the surface, which tests the contact force between the tip and the surface.

Adsorption experiments
A 10 mg / L CIP working solution was prepared by dissolving 0.01 g CIP in 1 L of deionized water. Before adding nanoparticles, the pH of the solution was adjusted. In this study, batch tests were conducted to evaluate the efficiency of CIP removal. The experiments met several working parameters, including pH within the range of 2 to 10, Cu-NPs dosages between 0.1 and 1 g / L, duration of contact of up to 180 min, initial CIP antibiotic concentrations between 2 and 15 mg /L, and temperatures between 20 and 50 °C. A specific amount of Cu-NPs was added to the CIP antibiotic solution, and then it was stirred at 300 rpm in a closed system. The pH of the solution was adjusted by 0.1 M H 2 SO 4 and 0.1 M NaOH. Temperature was maintained and the optimized value of each parameter was recorded. 10 mL samples were taken for analysis at different intervals during the adsorption experiments. The initial CIP concentrations were compared with the calibration data obtained immediately upon each sample with UV / VIS spectrophotometer, using a 1cm quartz container with the absorption of 276 nm maximum wavelength. Reference (blank) Cu-NPs solutions were read before each measurement, with the same concentrations as those of the sample. Also, adsorption data on temperature effects in contact times were used with various starting concentrations and sorbent doses, particularly in thermodynamic, kinetic, and isothermal studies. Cu-NPs were evaluated based on the efficiency of removal (R %) and adsorbent capacity ; q e (mg/g) values for the removal of antibiotic contaminants from water solutions [27,28]. R % = (C 0 -C t ) *100/C 0 (1) q e = (C 0 -C e ) *V/W (2) where C 0 , C t, and C e denote the initial, at a specific time of adsorption, and equilibrium concentrations of CIP aqueous phase antibiotics (mg/L), respectively, V is the antibiotic solution volume in Liter, and W is the Cu-NPs adsorbent in (gm). The removal mechanism of the CIP onto Cu-NPs depends on the van der Waals forces interaction between adsorbent and adsorbate. As a result, the adsorbate transfers from the liquid phase to the boundary layer of the adsorbent, then the adsorbate transfers from the boundary layer to the external surface of the adsorbent. After that, the adsorbate at the outer surface transfers into the inner surface of the adsorbent by pore diffusion and, finally, the active interaction occurs between the molecules of adsorbate and the adsorbent [3]. In the closed system, several conditions were examined; wide range of the initial pH (2.5, 3, 4, 5, 7, 8, 9, 10), initial CIP concentration (2, 5, 10, 15 mg / L), Cu-NPs dose (0.1, 0.25, 0.75, 1 g / L) and temperature (20, 30, 40, 50 ° C). The performance of CIP removal was determined by Eq. (1).

Characterization of Cu-NPs
Scanning electron microscopy was utilized to analyze the structure, composition, and average size of the synthesized copper nanoparticles, as shown in Figure-2. The typical SEM picture demonstrates that the product consists mainly of spherical and monodispersed particles, with size distribution that ranges between 30 nm and 120 nm. Another observation that was noticed with high magnification shows, however, that these Cu-NPs are assembled from smaller and highly uniform nanoparticles with an average diameter of about 21 nm.  [20]. Figure-3 shows the wide peak at O-H at 3411 cm -1 , which indicates the presence of polyphenols, with the association between C-H asymmetrical stretching and certain signals in 2948, 1782, 1615 and 1029 cm -1 assigned for C=O of aromatic rings, C=C stretch, C-O-C and C-OH bending, respectively. Polyphenols can be assumed to work as reduction agents, as well as capping agents, in the green tea extract [29].

.1 Effects of Cu-NPs dose
The adsorbent dose is an important parameter because the capacity of the sorbent for a given initial adsorbent concentration is determined. The effect on ciprofloxacin removal is shown in Figure-6. The percentage of CIP removal raised from 20%, 29%, 41.6%, and 51.4 to 54.1% using different concentrations of Cu-NPs (0.1, 0.25, 0.5, 0.75, and 1 gm, respectively). With higher Cu-NPS concentration, the removal rate and effectiveness for CIP adsorption are increased, with the other parameter being maintained (pH, drug level, time of contact, and temperature).The increase in removal efficiency with the increased Cu-NPs dosage is due to the increase in the total area and the number of active sites [31,32]. Similar behaviors were also noticed in previous studies [23,33]. The optimal dose of copper nanoparticles used was 0.75 gm / L.

Effects of initial solution temperature
The temperature effect on the removal efficiency of the drug was examined at temperatures of 20-50 °C. Figure-7 indicates that the removal efficiency of CIP was altered in response to various temperatures. The CIP removal percentage was increased with increasing temperature by 43%, 43.5%, 78.4%, and 49.3%, at 20, 30, 40, and 50 ° C, respectively. This is because the viscosity of the solution may be lowered by increasing the temperature, which increases mobility by increasing the rate of diffusion of adsorbate through the external limit layer of the adsorbent [34], leading to the increase in adsorption capacity.. The optimal value of temperature was 40° C. A similar observation was noted by an earlier work [35].

Effects of initial pH of the solution
The effects of pH of the medium on CIP adsorption using NPs are shown in Figure-8. The results indicate that higher CIP adsorption could be based on two factors:(1) At pH 3, the H + concentration in the solution was very high, with an increased electrostatic attraction between the H+ solution and the adsorbent. CIP is achieved by increasing pH solution, so the competition for adsorption sites between H+ and the adsorbate is increased; and (2) At higher pH (>10), OHion concentration is increased and the adsorption is decreased, probably due to the competition between CIP molecules and OHions for the adsorption site [36]. Therefore, a physisorption reaction may occur between the CIP molecules and Cu-NPs active sites at pH=4. The removal efficiency values after sixty minutes at various pH levels (2.5, 3, 4, 5, 7, 8, 9, and 10) are 37%, 51.4%, 78.4%, 50%, 73.6%, 32.6%, 31%, and 27.5%, respectively. A similar observation was noticed in earlier investigations [37,38].   35.8% with the increase in the initial concentration of CIP from 2, 5, 10 to 15 mg/L, respectively. However, increasing the initial concentration to higher than 10 mg/L resulted in a decrease in the removal efficiency, The results obtained are consistent with those described in the literature [38,39]. The possible cause of these results is the initial CIP concentration and the number of active Cu-NPs sites, as they are likely to increase and lead to competitive adsorption of CIP molecules [33].

Effects of contact time
To determine the equilibrium point, the effects of the contact time are extremely important in the adsorption process. Figure-10 shows how the contact time increases at different pH values (4, 7, and 10). The CIP removal efficiency in the batch system increases with additional contact time. The adsorption process was initially rapid due to the driving force of the highest CIP concentration, after which the removal rate slowed for all pH values. This effect is due to the continuous decrease in the number of adsorbent active sites and the concentration of non-adsorbed CIP molecules. After 60 minutes, the CIP removal efficiency at pH values of 4, 7 and 10 were 80.7, 43.6 and 27.5%, while after 180 minutes the values were 92.3, 70.6, and 51%, respectively. A similar observation was found by other authors [27,35]. The optimal pH value was 4; with a maximum removal efficiency of 80.7% after 60 min and 92.3% after 180 min. Table-3

Adsorption Kinetics
The adsorption kinetics models have been studied. Four kinetic models were evaluated. The linear forms of the pseudo-first-order, the pseudo-second-order [45,11,46], Elovich [12,22], and Behnajady-Modirshahla-Ghanbary (BMG) models [19] are given in Eqs. (3)(4)(5)(6)(7), respectively: Log (q e -q t ) =log q e -k 1 t/2.303 Pseudo-first-order (3) t /q t = 1/k 2 q 2 2 + t/q e Pseudo-second-order (4) t /q t =1/h+ t / q e (5) q t = 1/ β ln (αβ) + 1/β ln (t) Elovich model BMG model (7) where q e and q t are the amounts of CIP adsorbed on the adsorbent (mg/g) at time t and equilibrium condition, k 1 and k 2 are the rate constants of the first order (min -1 ) and the second-order adsorption (g/mg. min) respectively, α (mg/g/min) and β (g/mg) are adsorption and desorption rate constants, C 0 and C t are the concentration of drug at time 0 and time t, respectively, m and b are two constant of BMG model. The rate constant k 1 (min -1 ) was calculated from the slope and intercept of Log (q eq t ) versus t shown in Figure-(11-a). The initial adsorption rate (h) was estimated by pseudo-second-order from equation (5). The h (mg/g min -1 ) values for the fixed concentration of CIP (15, 10, 5, 2 mg /L) were 0.5333,

Atiya et al.
Iraqi Journal of Science, 2021, Vol. 62, No. 9, pp: 2833-2854 2844 0.6922, 1.0102, and 1.3056, respectively. The low k 2 values parallel to h indicated rapid sorption at the beginning, followed by slower adsorption. The rate constants for the pseudo-second-order k 2 and q e were calculated from the intercept and slope of t / q t to the t graph, as shown in Figure-(11-b). k 1 (rate constant for the pseudo-first-order) was >k 2 for the pseudo-second-order, while the best-suited equation of Cu-NPs kinetic CIP adsorption was the pseudo-first-order [27]. Table-4 demonstrates that the first-order regression coefficient R 2 (0.9706) is better in comparison to the second-order R 2 (0.9113). The adsorption rate constant α (mg /g /min) and desorption rate constant β (g / mg) were obtained from the slope and intercept of q t versus ln (t), as shown in Figure-(11-c). The α and β for 15, 10, 5 and 2 mg / L showed higher adsorption rates (0.8537, 1.5507, 1.9151, 2.3666) as compared to desorption rates (0.7018, 0.4690, 0.4580, 0.4052), respectively. Table-4 shows that the highest regression coefficient value of the Elovich model was 0.9619. For adsorption of the CIP in different conditions, the parameters m (min) and b of the Behnajady-Modirshahla-Ghanbary (BMG) kinetic models were calculated from the slope and intercept of t versus t /[1-(C t / C 0 )],, as shown in Figure-(11-d). When the concentration of CIP increased from 2 to 15 mg / L, the values for m and b increased from 10.193 to 24.876 and from 0.9379 to 1.9693, respectively. This indicates that the time of the adsorption process is increased when the CIP concentration increases, as shown in Table-4. The kinetic data showed that the BMG model regression coefficient value R 2 is 0.9113, as shown in Table-4. Table-4 shows that the best kinetic pseudo-first-order model is due to the higher R 2 (0.9704) value than other kinetic models. Several research papers [4,18,44] have already shown this deviation.

Adsorption mechanism
Equations (8) and (9) [47,35,18] were used for determining the mechanism of adsorption. Intraparticle diffusion kinetic model: q t = K id t 0.5 +C (8) Liquid film diffusion kinetic model: Ln (1-q t /q e ) = -K fd t (9) where q t indicates the amount of CIP molecules adsorbed (mg/ g) at t time (min) and q e denotes the amount of CIP molecules adsorbed (mg / g) at equilibrium. The intraparticle diffusion constants K id (mg/g min 0.5 ) and C (mg /g) indicate the boundary layer thickness, while K fd (m -1 ) is the fluid film diffusion constant. In the event that the linear trend line is passing or is near to the origin of the trend line (C=0), the intraparticle diffusion is the limiting rate step. The plot of ln (1-q t /q e ) versus t Figure-12-b) obtained slopes and intercepts related to K fd and C [48]. Table-5 shows the results from experimental information with intraparticle and film diffusion at different initial CIP concentrations. It is observed that the straight lines in Figures-(12-a) and (12-b) does not pass through the original line. This observation indicates that the adsorbing process is controlled by the thickness of the limit layer, while the high regression coefficient values suggest that the intraparticle diffusion (R 2 =0.9879) is more applicable [27]. The C values indicate that the spread liquid film diffusion may also be involved in the process of adsorption. The diffusion of the intraparticles is not the only rate control process. Other adsorption and diffusion mechanisms have been described in various research papers [27,49].
Log q e = (1/n) log C e + log k F (12) Temkin model calculation is shown by equation 13. q e = (RT/B T ) ln C e + (RT/B T ) ln K T (13) Dubinin model calculation is shown by the following equations.
Ln q e = ln q m -βε 2 (14) ε =RT ln (1+1/C e ) where C e and q e are the concentration and amount adsorbed of CIP at equilibrium. q max and b are Langmuir constants. These values were calculated from the slope and intercept of the graph that plotted C e /q e versus C e , as shown in Figure-(13-a). The results were well defined by Langmuir isotherm, where (R 2 ) value is higher by using Langmuir as compared to Freundlich. Homogeneous adsorbent surfaces should exist on Langmuir with the same adsorption sites. The Freundlich isotherm is an empirical equation that is supposed to perform the adsorption procedure on the heterogeneous surface through a multilayer adsorption mechanism. As shown in Table-6, Langmuir constant b was established at 2.1307 for Cu-NPs. The adsorption nature of the R L indications are unfavorable when R L > 1, linear when R L = 1, favourable when 0 < R L < 1, or irreversible when R L = 0, where R L is a dimensionless constant usually referred to as the separation factor [46]. The R L value achieved for Cu-NPs adsorption was in the range of 0.04504-0.0449; therefore, CIP adsorption was favorable for adsorbents as they ranged between 0 and 1. The maximum uptake (q max ) was 5.5279 mg of CIP per gram of the Cu-NPs. The Freundlich coefficient values k F and n were determined from the slope and intercept, as shown in Figure- (Table-6), with minute changes in sorption heat and robust interactions between adsorbate and adsorbent. q m and β can be determined from the intercept and slope of the plotted graph ln q e vs. ε 2 shown in Figure-(13-d). From Eq.15, the E value was 0.8409kJ / mol, which indicates physical adsorption. Figure-(13a-d) shows four models of adsorption isotherms, together with experimental CIP data. The Dubinin and Langmuir models provided the better fitting in terms of R 2 (0.9963 and 0.9626, respectively) with maximum adsorption capacity q max = 1.1069 and 5.5279 mg/g, respectively. A similar observation was noticed in various researches [52][53][54].

3.6.Adsorption Thermodynamics
The adsorption behaviors of different concentrations of CIP onto Cu-NPs were explored at 298, 303, 313 and 323 K. The thermodynamic parameters of enthalpy, entropy, and Gibbs free energy were calculated from equations 17 to 19 [55,20,56].
∆G 0 = -RT ln K eq (17) K eq = q e /C e (18) Ln K eq = -∆H 0 /RT + ∆S 0 /R (19) where T, R, and K eq are absolute temperature (K), universal gas constants (0.008314 kJ / mol K -1 ), and the distribution coefficient, respectively. C e and q e (mg /g) are the equilibrium concentration and the amount of adsorbent at equilibrium, respectively. Gibbs free energy (∆G 0 ) was calculated using ln ln q e ε 2 d K eq values for different temperatures. Enthalpy (∆H 0 ) and entropy (∆S 0 ) were determined from the slope and intercept connected to ΔH 0 and ΔS 0 of the plot of ln K eq versus 1/T, as shown in Figure-(14a), according to Eq.19. Table-7 shows the values of free energy, enthalpy, and entropy. The positive ∆H 0 value showed favorable and endothermic sorption. The negative free energy (∆G 0 ) indicates the spontaneous nature of the CIP adsorption on Cu-NPs [53, 55, and 56]. The positive entropy (∆S 0 ) change indicates the increase in interruption at the solid-liquid interface during the adsorption process [52]. The activation energy (E a ) was calculated by applying Eq.21 [57, 58, and 39]. A is the Arrhenius factor, R is the gas constant (8,314 J/mol. K), K is the temperature in Kelvin, Ea is the activation energy (kJ/mol), and k obs (min -1 ) is the rate constant calculated from Eq. 20. E a is calculated by the slope and intercept of ln(C t / C 0 ) against time t(min). The straight line of ln k obs against 1/T, shown in Figure-(14-b), the activation energy is 13.22 kJ/mol, indicating controlled diffusion process, whereas a value of E a greater than 20 kJ / mol is attributed to a processes with chemical controls [59,53]. ln (C t /C 0 ) = -k obs t (20) ln k obs = ln A-E a /RT (21) Figure 14-Relationship between (a) Ln K eq against 1/T for thermodynamic constants determination of CIP adsorption onto Cu-NPs, (b) ln k obs against 1/T to estimate E a at the initial concentration of 10 mg/L, pH=4, and 300 rpm for adsorption of CIP with a dose of 0.75 gm and 60 min contact time. Table 7-Thermodynamic examination of the adsorption of CIP onto Cu-NPs(initial concentration 10 mg/L, Cu-NPs dose 0.75g/L, contact time 60 min, agitation speed 300 rpm, and pH=4). This study examined the adsorbent performance of Cu-NPs in the batch system concerning CIP adsorption. Advanced SEM, AFM, BET, zeta potentials, and FT-IR analyses were used to characterize the Cu-NPs adsorbent. The characterization results show that the Cu-NPs nanoparticles have positive effects in terms of use and adsorption on the prepared adsorbents. The parameters of the adsorption process were optimized with pH, contact time, initial antibiotic concentration, temperature, and Cu-NPs dose values of 4, 60 min, 10 mg/L, 40°C, and 0.75 gm/L, respectively). The isothermal, kinetic, and thermodynamic studies were conducted based on the data of the optimized impact study. The isothermal study show that the surface of Cu-NPs consists of a homogenous adsorption site that is ready for reaction of antibiotic molecules. The mechanism of the adsorption process was the intraparticle diffusion process. The spontaneous and endothermal nature of the adsorption process was underlined by the thermodynamic element. In future studies, one should identify the effects of the agitation speed, the size of nanoproducts, and the size of the magnetic bar on the adsorption of Cu-NPs as a result of the kinetic data were modeled and the adsorption trend was observed to obey the Pseudo-first order kinetic model for CU-NPs indicating the physisorption mechanism onto this adsorbent for the drug (CIP) studied.