Smart Cities are considered the intersection of technology and urban development, aiming to create sustainable, efficient, and citizen-centered environments using advanced tools such as the Internet of Things, artificial intelligence, and big data analytics. The major components of a smart city are smart buildings, smart transport, smart energy, smart health care, public safety and security, environmental and resource management, and smart technology. These components make the cities smart, transparent, and efficient. Information and communication technology is one of the most vital tools for modifying traditional cities into Smart Cities. Smart Cities are emerging as transformative urban ecosystems that leverage data, technology, and intelligent design to enhance sustainability, efficiency, and the quality of life for residents. Over 1,000 cities worldwide are developing or implementing smart city initiatives, with projected investments exceeding $1.5 trillion by 2025. Studies indicate Smart Cities can achieve up to 30% reductions in energy consumption and 20% improvements in public service efficiency. This paper presents a systematic review of 61 scholarly works, highlighting the benefits, challenges, and the central role of telecommunications in smart urban development. This systematic review dissects the dual nature of Smart Cities regarding their revolutionary capabilities and intrinsic challenges. The study points out important gaps in the literature, especially when it comes to long-term social effects, fair resource allocation, critical gaps in ethical governance, resource distribution policies, and their long-term implications on societal development, and ethical governance, underrepresentation of telecommunications as a central enabler, and propose future research directions to address these gaps.

The objective of this research is to explore the production of biodiesel using Waste Vegetable Oil (WVO) as the primary feedstock and calcined eggshell ash as an environmentally sustainable catalyst. The WVO, characterized by a Free Fatty Acid (FFA) content of 2.86%, serves as the primary feedstock for biodiesel production through transesterification. The eggshell ash undergoes a rigorous process, including washing with distilled water to remove impurities, drying at 100ºC for 24 hours, crushing into fine particles, and final calcination in a muffle furnace at 900ºC. Process optimization is achieved by varying key reaction parameters, including temperature, catalyst loading, and the methanol-oil molar ratio. The optimal conditions are identified at 65°C, utilizing a methanol-oil molar ratio of 6:1 and a 5wt% catalyst loading. Under these optimized reaction conditions, a substantial biodiesel yield of 91.3% is obtained. The produced biodiesel meets the stringent quality requirements specified by the American Standard (ASTM D 6751) and European Standard (EN 14214) for biodiesel fuel, ensuring its suitability for various applications. This study demonstrates the potential of utilizing calcined eggshell ash as an eco-friendly catalyst for sustainable biodiesel production from WVO. Received: 20 September 2023 | Revised: 1 November 2023 | Accepted: 13 November 2023 Conflicts of Interest The authors declare that they have no conflicts of interest to this work. Data Availability Statement Data sharing is not applicable to this article as no new data were created or analyzed in this study. Author Contribution Statement Favour Okechi Ifeanyi-Nze: Conceptualization, Methodology, Validation, Formal analysis, Investigation, Resources, Data curation, Writing - original draft, Writing - review & editing, Visualization, Supervision, Project administration; Charles Olumakinde Omiyale: Conceptualization, Validation, Writing - review & editing; Innocent Ugochukwu Okonkwo: Formal analysis, Investigation; Chinemerem Jerry Chukwu: Methodology, Visualization; Chidimma Maryjane Nwankwor: Writing - original draft; Adebola Olatunde Onabanjo: Data curation; Sarah Onyabakpa Adoga: Project administration; Johnson Obasi Chukwu: Supervision; Kenechukwu Fortunate Chukwurah: Writing - review & editing, Project administration; Marcus Ebikemiyen: Investigation; Godstime Uduak Okon: Resources; Olaoluwa John Adeleke: Data curation; Kazeem Arowosaye Tajudeen: Validation.

Wastewater discharged from the textile industry poses significant environmental and societal challenges due to the presence of hazardous dye pollutants. This study explores a novel approach for the removal of methylene blue, a common textile dye, from water using adsorbents derived from orange peels. The goal is to mitigate water pollution, thereby reducing harm to ecosystems and living organisms, while simultaneously addressing the issue of environmental litter generated by discarded orange peels. In this study, the removal of methylene blue dye from textile wastewater using adsorbents made from orange peels was examined. Orange peels were collected, washed, dried, charred at 500 °C, ground into powder, and activated with phosphoric acid to create an activated carbon with a bulk density of 0.987 g/mL, 15% moisture, 3% ash content, and a surface area of 52.5 m²/g. It was found that adsorption rates increased over time, reaching equilibrium after 120 minutes, with a maximum removal efficiency of 90% achieved using 0.6 g of adsorbent. The study concluded that orange peel-derived adsorbents could be an effective and eco-friendly method for reducing water pollution and repurposing agricultural waste, presenting a viable solution to the environmental challenges posed by the textile industry. Received: 27 November 2023 | Revised: 5 February 2024 | Accepted: 21 March 2024 Conflicts of Interest The authors declare that they have no conflicts of interest to this work. Data Availability Statement Data are available from the corresponding author upon reasonable request. Author Contribution Statement Kazeem Arowosaye Tajudeen: Conceptualization, Methodology, Validation, Formal analysis, Investigation, Supervision, Project administration. Favour Okechi Ifeanyi-Nze: Conceptualization, Methodology, Validation, Formal analysis, Investigation, Resources, Data curation, Writing — original draft, Writing — review & editing, Visualization, Supervision, Project administration. Johnson Obasi Chukwu: Conceptualization, Validation, Investigation, Writing — review & editing. Olaoluwa John Adeleke: Formal analysis, Visualization. Nathaniel Nwoke Chimezie: Formal analysis, Data curation. Chukwudi Moses Ihezie: Resources. Muhideen Oyetunji Oyewole: Writing — review & editing. Chinecherem Favour Edeh: Supervision. Bethel Chijioke Iheanacho: Resources. Oluwakemi Oluwatobi Onabanjo: Methodology. Oluwafemi F. Olaiyapo: Validation. Chinemerem Jerry Chukwu: Validation. Adebola Barakat Quadri: Project administration. Rasheed Nurudeen Mobolaji: Writing — original draft. Rebecca Temitope Okunola: Data curation. Fon Alain Zoum: Formal analysis. Moses Godwin Udoisoh: Investigation. Dolapo Abidemi Kolapo: Visualization. Kasim Ismail Abdullahi: Formal analysis, Investigation.

An Advanced Metering Infrastructure (AMI) plays a crucial role in modernizing power distribution networks, providing benefits to both utilities and consumers. Its ability to collect and analyze data in real-time contributes to a more efficient, reliable, and responsive electricity supply system. This paper introduces an Energy Monitoring System (EMOSY), an IoT-enabled AMI tailored for Nigeria's power distribution network with an unstable grid connection in Ibadan, Nigeria. The EMOSY, an IoT-enabled platform, facilitates real-time monitoring of electrical parameters, addressing the specific challenges and demands of Nigeria's electricity system. The system was implemented, and data were collected from May 24, 2024, to June 8, 2024, revealing a stable average voltage of 222.50 V and consistent energy costs ranging from 0.93 to 1.24 Naira $\mathbf{N}\!\!\!\!\!\!\!$=. This study not only showcases the system's successful implementation but also sets the stage for future integration of AI for predictive analysis, enhancing EMOSY's capability in anticipating and managing energy demands and challenges specific to Nigeria.

The utilization of renewable biomass resources for biofuel production has gained widespread popularity as an effective means of converting waste into a valuable resource. This study investigated the optimization of biodiesel production from coconut oil (CO) using a bifunctional catalyst derived from crab shell and coconut shell. The catalyst underwent characterization through Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and Brunauer-Emmett-Teller. The acid precursor for the bio-based bifunctional catalyst was created from carbonized and sulfurized coconut shell, while the base precursor was obtained from calcined and KOH-treated crab shell. The experimental design was optimized using Box-Behnken design for the simultaneous esterification and transesterification of CO. Response surface methodology was employed to model and optimize the process. Under the determined ideal conditions, which included a methanol to oil ratio of 16.75:1, a 1.00% catalyst loading, a temperature of 58.19 °C, and a reaction time of 78.76 minutes, a CO methyl ester yield of 85.73% was achieved under experimental conditions. This yield closely aligned with the predicted range of 85.84% as per the model. The resulting methyl ester (biodiesel) obtained under these optimized conditions exhibited physicochemical properties well within the requirements specified by ASTM D6751 set by the International Organization of Standardization.

Brewers’ spent grain (BSG), the primary by-product of the brewing industry, constitutes approximately 85.0% of the total by-products generated. BSG is known for its rich cellulose and non-cellulosic polysaccharide content, making it a valuable resource with significant potential for profitable recycling and reutilization. Given that the brewing sector is among the most substantial industrial consumers of water due to the water-intensive process of producing BSG, the effective management of wastewater in this industry is of paramount importance. This research focuses on investigating innovative wastewater management in the brewing sector. It employs the conversion of BSGs into a cellulose acetate membrane, thus enabling a physio-chemical treatment process utilizing the micro-filtration technique for wastewater treatment within the brewery industry. The results of this study demonstrate a substantial reduction in biochemical oxygen demand from the initial value of 16.65 mg/l (untreated) to 13.70 mg/l, 11.16 mg/l, 8.37 mg/l, 5.58 mg/l, and 3.14 mg/l after the first through fifth treatment cycles, respectively. Furthermore, the research indicates a high correlation with an R2 value of 0.999, affirming the viability and effectiveness of the treatment process. This is further substantiated by the results of chemical oxygen demand, total dissolved solids, total suspended solids, and hydrogen ion concentration analyses presented in this study. These findings not only validate the efficacy of utilizing BSG-derived cellulose acetate membranes but also emphasize the potential for revolutionizing wastewater treatment practices within the brewing industry. This research paves the way for sustainable, environmentally conscious strategies in industrial wastewater management, ensuring the optimal utilization of by-products while minimizing the environmental footprint of brewing operations.