## 3 Results and Discussion
### Material Characterization  
3.1.1. X-Ray Diffraction (XDR)  
The XRD patterns for the Hap series (Hap-H1, Hap-H2, Hap-H3, and Hap-H3 750), FCF, and Hap-FCF are displayed in Figure 1, where the materials, except for FCF, were synthesized using the co-precipitation method, assisted during the crystallization stage by simultaneous Microwave-Ultrasound Irradiation (MO-US).  
For the Hap series, XRD patterns show reflections at 2\(\upmu\) values of (26, 32, 33, 34, 39, 47, 49, and 54) degrees corresponding to the (002), (211), (300), (202), (310), (222), (213), and (004) planes, respectively, which are characteristic of hydroxyapatite according to the card (JPCDS No. 09-0432) [25], corresponding to a compact hexagonal unit cell.  
Based on the (211) peak, the Hap-H3 750 sample demonstrates the highest crystallinity, followed by the Hap-H2, Hap-H3, and Hap-H1 samples. Applying the Scherrer equation to the width of this peak, the smallest crystal size was calculated for the Hap-H3 sample (17 nm), followed by Hap-H3 750 (18 nm), Hap-H2 (29 nm), and Hap-H1 (45 nm).  
In the case where the Hap-H3 sample was heated to 750 \({}^{\circ}\)C to form the Hap-H3 750 sample, no phase transition is observed as no new peaks appear. Instead, an increase in intensity is observed in the (002), (210), (211), (300), (222), and (213) planes, indicating that the material only underwent a crystallographic rearrangement due to the temperature effect.  
The observed crystal sizes correlate with the milling method applied to the precursor material, as all samples were synthesized under identical microwave/ultrasound power and irradiation conditions. The calcium precursor sieved to a smaller particle size (mesh #170) yielded the smallest crystal size of 17 nm (Hap-H3); this sample subsequently under  
Figure 1: XRD patterns of the samples Hap, FCF, and Hap-FCF composite.  
went thermal treatment at 750 \({}^{\circ}\)C, following the procedure by [PERSON] et al. [26], resulting in the Hap-H3 750 sample with a crystal size of 18 nm. This treatment improved the material's ordering compared to Hap-H3, as indicated by the higher intensity of the (002) peak (Figure 1).  
It can be observed that, through the simultaneous MO-US irradiation method, pure Hap free of crystalline impurities was obtained in all cases, reducing the synthesis times from the hours reported using the conventional sol-gel method [27] and the neutralization method [28] to just 10 min. Scaling up to an industrial level is entirely feasible, and some industries already use commercial reactors with microwave irradiation for the synthesis, extraction, cleaning, drying, and calcination of materials. However, the combined use of these technologies (MO-US) with ultrasonics has not yet been implemented on an industrial scale. One of the main challenges in implementing such synthesis technologies is the need for more knowledge regarding the existence of alternative heating sources. For their implementation, a cost-benefit analysis would be necessary, which was not the focus of this study. Nevertheless, by reducing the synthesis time from hours to minutes, energy costs decrease significantly in addition to the ability to manipulate the texture of the resulting materials, which depends on the time and microwave-ultrasonic irradiation power.  
For forchlorforneuron, characteristic peaks at the (102), (200), (140), and (230) planes, identified using the methods described in [PERSON] et al. [29] and HighScore Plus software version 3.0, were confirmed. In the Hap-FCF sample, peaks from both components are observed, with Hap signals predominating, indicating the effective integration of the two, with no additional peaks detected. The composite exhibits a 10\({}^{\circ}\) peak shift for both compounds, likely due to structural changes from their interaction, as suggested by [PERSON] et al. [30], along with decreased peak intensities reflecting a reduction in crystallinity.