In the present research, we describe a novel approach for in situ synthesis of cellulose microfibrils-grafted-hydroxyapatite (CMFs-g-HAP_N (8%)) as an adsorbent using phosphate rock and date palm petiole wood as alternative and natural Moroccan resources. The synthesized CMFs-g-HAP_N (8%) was extensively characterized by several instrumental techniques like thermogravimetry analysis, Fourier transform infrared spectroscopy, X-ray diffraction, ³¹P nuclear magnetic resonance, scanning electron microscopy, and Brunauer-Emmett-Teller analysis. The developed adsorbent was used to remove Pb(II) and Cu(II) from aqueous solutions. The influences of different adsorption parameters such as contact time, initial metal concentration, and amount of adsorbent were also investigated thoroughly using response surface methodology in order to optimize the batch adsorption process. The results confirmed that the adsorption process follows a polynomial quadratic model as high regression parameters were obtained (R ² value = 99.8% for Pb(II) and R ² value = 92.6% for Cu(II)). According to kinetics and isotherm modeling, the adsorption process of both studied ions onto CMFs-g-HAP_N (8%) followed the pseudo-second-order model, and the equilibrium data at 25 °C were better fitted by the Langmuir model. The maximum adsorption capacities of the CMFs-g-HAP_N (8%) adsorbent toward Pb(II) and Cu(II) are 143.80 and 83.05 mg/g, respectively. Moreover, the experiments of multicycle adsorption/desorption indicated that the CMFs-g-HAP_N (8%) adsorbent could be regenerated and reused up to three cycles. The high adsorption capacities of both studied metals and regeneration performances of the CMFs-g-HAP_N (8%) suggest its applicability as a competitive adsorbent for large-scale utilization.

As the demand for sustainable and environmentally friendly energy sources continues to rise, biodiesel has emerged as a promising alternative fuel derived from renewable feedstocks. This book chapter explores the pivotal role of catalysis in the sustainable production of biodiesel fuel. Catalytic processes play a crucial role in converting renewable feedstocks, such as vegetable oils and animal fats, into biodiesel through transesterification and esterification reactions. The chapter provides an overview of various heterogeneous and homogeneous catalysts utilized in biodiesel production, highlighting their advantages and limitations. Furthermore, the impact of catalyst properties, such as acidity, basicity, and surface area, on the efficiency and selectivity of biodiesel synthesis is discussed. By elucidating the critical role of catalysis in sustainable biodiesel production, this chapter contributes to ongoing efforts in developing renewable energy sources and reducing carbon emissions. <!----> <!----> <!----> <!---->