This chapter examines the sustainability challenges of AI-intensive and high-performance computing (HPC) data centers, focusing on cooling technologies and their impacts on energy and water use. It situates these infrastructures within the broader energy–water nexus and compares major cooling approaches—air, water-based, and liquid—using key metrics such as PUE, WUE, and CUE. The chapter highlights how the rapid growth of AI workloads, marked by high power densities and dynamic thermal constraints, increases resource demand and complicates thermal management. It also explores regional variations, showing how climate, water availability, and electricity mix affect sustainability outcomes. By integrating technical, environmental, and policy perspectives, it identifies trade-offs between energy efficiency and water consumption and emphasizes context-aware design. Ultimately, it argues that combining thermal modeling, energy optimization, hydrological analysis, and carbon assessment supports more informed infrastructure and location decisions.

The regeneration performance of ZnFe 2 O 4 in wastewater treatment is highly dependent on its degree of inversion. This study systematically investigates the relationship between inversion degree and photocatalytic efficiency of ZFO MNPs for degrading industrial pollutants under solar irradiation. ZFO nanoparticles are synthesized via co‐precipitation and subjected to thermal annealing at temperatures ranging from 550 to 950 °C to control their structural properties. Comprehensive characterization revealed that increasing annealing temperature progressively reduced the inversion degree from 0.54 to zero, as determined by Rietveld refinement of X‐ray diffraction data. This corresponds to a structural transition from intermediate mixed spinel to normal spinel configuration, driven by thermally‐induced iron cation migration within the crystal lattice. The structural evolution directly influenced the electronic properties, causing bandgap redshift and modifying photogenerated electron‐hole pair recombination dynamics, as confirmed through Mott‐Schottky analysis and photocurrent measurements. The inversion degree, along with crystallite size and spin disorder, significantly affected the saturation magnetization of ZFO samples. The molecular simulations revealed that the electrostatic interactions dominate the adsorption of methylene blue (MB) onto ZFO. Photocatalytic experiments demonstrated that the intermediate spinel structure (annealed at 550 °C, x = 0.54) exhibited optimal performance, achieving 97% MB degradation within 70 min under solar irradiation. This enhanced activity is attributed to improved charge separation efficiency and reduced electron‐hole recombination in the inverted spinel structure.

In the present investigation, we study the effect of the calcination temperature on the stability of sulfate ions in nano-sulfated zirconia, which play an important role in water defluoridation. Nano-sulfated zirconia adsorbents were developed for fluoride uptake from water. It showed excellent efficiency for Tunisian tap water treatment. This performance is due to the particular synthesis process using sol–gel approach in one- pot coupled to supercritical drying. The morphology and structure of the prepared materials were examined using N2 physisorption, FTIR spectroscopy, SEM, pHPZC, XRD, TEM and EDX spectroscopy. Textural properties revealed that all prepared nanoscale materials develop a mesoporous texture, a high porosity, and a large surface area, reaching 340 m2 g−1. FTIR spectroscopy and SEM analysis showed the formation of highly functionalized solids with various active sites and numerous cavities. TEM results confirmed the nanocrystalline nature of our solids. The different findings indicated that the functionalization of zirconia produces a particular material’s structure affected by calcination temperature. In the broad pH range of 2–8, the selected nano-sulfated zirconia exhibited a high fluoride removal rate of almost 99

Two-moved bed biofilm reactors were used for nitrogen (N) removal from Tunisian secondary effluent. The first one is aerated MBBR with a volume of 1 m3 and filled to 44

The regeneration performance of ZnFe2O4 in wastewater treatment is highly dependent on its degree of inversion. This study systematically investigates the relationship between inversion degree and photocatalytic efficiency of ZFO MNPs for degrading industrial pollutants under solar irradiation. ZFO nanoparticles are synthesized via co-precipitation and subjected to thermal annealing at temperatures ranging from 550 to 950 degrees C to control their structural properties. Comprehensive characterization revealed that increasing annealing temperature progressively reduced the inversion degree from 0.54 to zero, as determined by Rietveld refinement of X-ray diffraction data. This corresponds to a structural transition from intermediate mixed spinel to normal spinel configuration, driven by thermally-induced iron cation migration within the crystal lattice. The structural evolution directly influenced the electronic properties, causing bandgap redshift and modifying photogenerated electron-hole pair recombination dynamics, as confirmed through Mott-Schottky analysis and photocurrent measurements. The inversion degree, along with crystallite size and spin disorder, significantly affected the saturation magnetization of ZFO samples. The molecular simulations revealed that the electrostatic interactions dominate the adsorption of methylene blue (MB) onto ZFO. Photocatalytic experiments demonstrated that the intermediate spinel structure (annealed at 550 degrees C, x = 0.54) exhibited optimal performance, achieving 97% MB degradation within 70 min under solar irradiation. This enhanced activity is attributed to improved charge separation efficiency and reduced electron-hole recombination in the inverted spinel structure.

As a subset of the Industrial 4.0 revolution, 3D printing is a machine that is closely monitored through data acquisition. It has gained significant attention in various applications, including prototyping and manufacturing, electronics, medicine, education, and sensing. One particularly important area of development is in 3D-printed sensors, which represent the next generation of sensor technology and have relevance in both research and industry. Commercial 3D printing materials and systems have recently been successfully utilized to fabricate these sensors, demonstrating their accuracy, efficiency, and maturity. This chapter focuses on the latest advances in 3D-printed sensor technology, examining the structure design, fabrication methods, performance, and applications across a wide range of fields. The authors recognize that material selection and functionalization methods with nanomaterials must be tailored to specific application requirements. Therefore, this chapter also discusses the integration of nanomaterials in the design of 3D-printed sensors, providing readers with greater insight into this next generation of sensor technology.

In this work, a series of bimetallic nano-oxide ZrO2–CeO2 xerogel adsorbent with different Ce/Zr molar ratio (0.1, 0.2, 0.3 and 0.5) were prepared in one step via sol–gel method in order to obtain the highest-performing composition for fluoride removal from drinking water. BET, SEM, EDX, TEM, FTIR spectroscopy, and XRD techniques were performed to characterize the solids before and after fluoride adsorption. The selected material exhibits a high surface area (SBET = 255 m2 g−1) and a large porosity (VP = 0.30 cm3 g−1). FTIR spectroscopy demonstrated the significant role played by the adjunct sulfate anion and superficial hydroxyl groups in the defluorination process. Thermodynamic study confirms that the sorption is spontaneous and endothermic. Our adsorbent's behavior for the removal of fluoride is described by the Freundlich isotherm model. The pseudo-second order kinetic model represents the adsorption kinetic process. Less than 1 min, 100

In Tunisia, in order to meet water needs, there has been an overexploitation of aquifers. This has led to the degradation of groundwater quality. Therefore, groundwater became loaded with salts (up to 2000 mg L−1) and nitrate, which exceed 200 mg L−1 in the region of Bizerte. Electrocoagulation (EC) in the batch mode was proposed as an alternative method for the denitrification of groundwater polluted with nitrate (148 mg L−1) and chloride (from 0 to 2000 mg L−1). Nitrate removal yield decreased with the increase in Cl− concentration. It decreased from 100 to 63.5

The generated brine from the desalination unit hurts the environment. In this work, we try to valorize the nanofiltration and reverse osmosis brine generated from a hybrid desalination unit of treated wastewater located in Tunisia by magnesium recovery and reuse it as a cheap resource for fertilizer production. The brine was first purified by calcium removal. The pH of calcite precipitation was 11.32 and 9.78 using brine NF and brine RO respectively. After that, the filtrate was used to produce brucite. The pH of brucite precipitation was 11.3 and 9.74 for NF and RO brine respectively. 55 % of magnesium was recovered from NF brine and 65.5 % from RO respectively. To obtain a 100 % recovery rate of magnesium for brucite precipitation, the optimal molar alkaline reagent/Mg ratio was 5.5 and the pH was 11.9. The brucite was dissolved in sulfuric acid, then the Epsomite fertilizer was extracted with pure ethanol. The highest weight of epsomite was obtained for a volume ratio of acid/ ethanol of 0.8:3.5. The second fertilizer produced using brine magnesium was struvite. It was obtained for pH 9 and 11 using H2NH4PO4 acid and wastewater as a source of ammonia and phosphate respectively. 90 % and 50 % of magnesium recovery were obtained for the first and the second cases respectively. The infrared spectrum and X-ray diffractogram confirmed the brucite, epsomite, and struvite production using brine magnesium.

The current study investigates the effect of adding a low-cost biomaterial (sawdust biomass) to kaolinite clay on the properties of insulating refractory materials. Natural kaolinite clay from NW Tunisia has been selected for porous ceramic preparation due to its high alumina content (23.64%) with low impurities, especially iron and alkaline oxides. For this study, a set of cylindrical samples were prepared from mixtures of Tabarka clay with different proportions of sawdust (10, 15 and 20%). Those green specimens were pressed and sintered to 1350 degrees C for 2 h. Experimental data showed that the increase in sawdust proportion increased the open porosity from 24 to 35%. SEM images showed higher important porosity with higher biomass addition. Similarly, bulk density and compressive strength decreased to 1.65 g/cm3 and 17 MPa, respectively. Mullite phase was also generated by the abundant alumina and silica in the raw feed. Several ceramic specimens were also manufactured under optimal conditions: sawdust (20%), pressure (10 kN), and sintering at 1200, 1250 and 1300 degrees C. The obtained ceramics showed higher porosity (57%), but lower bulk density (1.13 g/cm3). These are the required standards for silicaalumina insulating materials, confirming the possible valorization of kaolinite clay from Tunisia for refractory insulating ceramic.

A case study of galvanization wastewater treatment was carried out to preserve the environment and to suggest a solution to the Metal Galvanization of Poulina Group Holding MBG-Galva industry located in Tunisia for reducing effluent organic matter, heavy metals, and salt contents. The current industry had two baths of rinsing water after steel degreasing and pickling steps. The chemical oxygen demand (COD) and pH of the first bath were very high compared to the second bath, which exhibits a low pH with high salinity and high heavy metals contents. Coagulation-flocculation and electrodialysis were examined as treatment processes for rinse water obtained after steel degreasing, while precipitation-oxidation and membrane distillation were combined for pickling rinse water treatment. Aluminum sulfate and sodium alginate were used, respectively, as coagulants and flocculents under optimal conditions determined through the Jar test. After the electrodialysis step, the removal rates were found to be 89.6% for conductivity, 93% for COD, 90 to 96% for salt content, and 82% to 99.5% for heavy metals. For the second effluent, the conductivity of wastewater was reduced by 97%, and heavy metals and COD were removed. The lab-scale experiment implementation proved that using the current process has a high impact on obtaining zero liquid reject in the manufactory, and reusing it in the same bath is an opportunity for water preservation. Solid waste characterized by X-rays showed that lead oxide and iron can be recovered from galvanization industry wastewater. Scaling the combined pretreatment and desalination system in a demonstration unit helps the galvanization industry reuse the water in the same industry and prevent environmental pollution.

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Combined electrocoagulation (EC) and electrooxidation (EO) process was applied to increase Tunisia's drinking water potential from a highly sulfate and nitrate contaminated groundwater. Firstly, batch EC experiments were carried out using Al electrodes under current density (7.2 to 59.5 mA cm(-2)), initial pH (3.0 to 11.0), and temperature (10.0 to 50.0 degrees C). The results showed that high removal efficiencies, 83.2 % and 82.1 % for sulfate and nitrate, respectively, were achieved at 42.8 mA cm(-2), initial pH 7.0, and 30.0 degrees C, while excessive amounts of 0.4 mg NO2-_N L-1 and 11.6 mg NH4+_N L-1 were produced. The mechanism study revealed that, at ambient temperature (20-30 degrees C), sulfate removal by adsorption on Al hydroxides was dependent of generated amount of hydroxide anions resulting from nitrate reduction into nitrogen by-products on the cathode. In second step, EO using a novel electrodes' combination (Ti/RuO2 anode and Ti cathode), under current density (7.5 to 30.0 mA cm(-2)), initial pH (8.5, 10.0), and initial temperature (10.0 to 50.0 degrees C), was implemented. The optimized conditions were found at 15.0 mA cm(-2), initial pH 8.5, and 20.0 degrees C, leading to complete removal of NO2- and NH4+ in the form of N-2 in <20 min.

Water is considered the most important life-giving source and indispensable for the endurance of all living beings. Dyes are used in most aspects of daily life, citing the painting of textiles, paper, and leather. Water pollution, especially with heavy metals, has emerged as a worldwide concern due to its numerous damaging effects on health and the environment. Several studies revealed that silver, gold, and magnetic nanoparticle-based adsorbents have shown outstanding performances in the extraction of heavy metals from wastewater. The outstanding performance of zero iron in the removal of heavy metals from wastewater is significantly influenced by its high reduction capacity and wide specific surface area. Numerous studies have demonstrated that factors such as particle size, surface chemistry, solubility, and shape are crucial in evaluating potential dangers and exposure from inhaled nanoparticles. The out-of-control growth of the world population leads to the continual growth of industrial, textile, pharmaceutical, and agricultural activities, resulting in the widespread use of contaminated wastewater.

Novel nanostructured platforms based on Pencil Graphite Electrodes (PGEs), modified with pyrene carboxylic acid (PCA) functionalized Reduced Graphene Oxide (rGO), and then decorated by chronoamperometry electrodeposition of MoS2 nanoroses (NRs) (MoS2NRs/PCA-rGO/PGEs) were manufactured for the electrocatalytic detection of hydrazine (N2H4) and 4-nitrophenol, pollutants highly hazardous for environment and human health. The surface morphology and chemistry of the MoS2NRs/PCA-rGO/PGEs were characterized by scanning electron microscopy (SEM), Raman, and X-ray photoelectron spectroscopy (XPS), assessing the coating of the PCA-rGO/PGEs by dense multilayers of NRs. N2H4 and 4-nitrophenol have been monitored by Differential Pulse Voltammetry (DPV), and the MoS2NRs/PCA-rGO/PGEs electroanalytical properties have been compared to the PGEs, as neat and modified by PCA-rGO. The MoS2NRs/PCA-rGO/PGEs demonstrated a higher electrochemical and electrocatalytic activity, due to their high surface area and conductivity, and very fast heterogeneous electron transfer kinetics at the interphase with the electrolyte. LODs lower than the U.S. EPA recommended concentration values in drinking water, namely 9.3 nM and 13.3 nM, were estimated for N2H4 and 4-nitrophenol, respectively and the MoS2NRs/PCA-rGO/PGEs showed good repeatability, reproducibility, storage stability, and selectivity. The effectiveness of the nanoplatforms for monitoring N2H4 and 4-nitrophenol in tap, river, and wastewater was addressed.

The technical-economic analysis of the hemodialysis water purification process, which uses reverse osmosis with sand, softeners, and granular-activated carbon as pretreatment steps, shows that the permeate conductivity exceeds 25 & mu;S cm(-1) at 25 & DEG;C due to softeners failure and that the cost of cubic meter of water produced is 2.4 euro. The purification unit generated brine with a conductivity above 5 mS.cm(-1) and it is discharged into the sewer. Several brine valorizations are proposed; brine recycling and simulation with IMS design software reveal that it is possible to recycle 0.2 m(3).h(-1) of brine and achieve 83% conversion rate with a good quality of permeate. The residual of the first reverse osmosis brine is diluted by the second reverse osmosis permeate and is to be used for toilet flushing, landscape irrigation, and sterilization steam production.

A tertiary treatment of the effluent received from five Tunisian wastewater treatment plants is implemented at GDA Sidi Amor for reuse in an aquaponic system. It includes a MBBR, a constructed wetland, sand and activated carbon filters, and a combined nanofiltration and reverse osmosis desalination system. The Results show that the post-treatment before desalination reduces the COD by 44 % which is mostly refractory, the orthophosphate by 33 %, and the ammonia by 95.6 %. The NF90 4040 removes 2/3 of the salts and micropollutants except for sodium, chloride and nitrate which are respectively 57 %, 45 %, 39 %. The micropollutants benzotriazole, and clarithromycin were removed by 17 %, and 8 % respectively. The optimum pressure for a conversion rate of around 80 % is 4.7 bar for the cold period and 7 bar for the summer period depending on water salinity and membrane fouling. After one year, membrane permeability decreases. After cleaning the conversion rate in-creases to 89 % at 5.2 bars and the hydraulic permeability increases by 39 %. Using the hybrid system NF-RO at 10 bars for RO BW30-4040 the amount of brine was reduced by 65 % and the permeate quality is improved. After five months, the total fish weight increases by 21 kg and the crops grow well.

Porous carbon materials have recently received interesting attention for their applications in various biomedical and bioscience fields. These porous materials possess unique properties such as high surface area, ordered porosity, good biocompatibility, easy functionalization, and high thermostability making them promising candidates. This chapter presented the latest advances in the use of porous carbon materials in terms of biosensors, medical diagnostics, and drug delivery applications. The authors admit that the choice of the synthesis and the surface functionalization protocols is directly related to the requirements of the application. Based on this, the design of porous carbon-based platforms is discussed to give to the readers more visibility.