Microalgae present an enticing alternative to conventional fossil fuel-dependent technologies for producing hydrogen, offering an intriguing and sustainable energy source. Numerous strains of microalgae are under investigation for their capacity to generate hydrogen, alongside various techniques and breakthroughs being developed to optimize the process. However, significant hurdles must be addressed for commercial viability, including the high manufacturing costs and the necessity for efficient harvesting and sorting methods. This paper delves into several aspects concerning hydrogen synthesis in algae, encompassing microalgae anatomy and physiology, hydrogen synthesis via photosynthesis and dark fermentation, and the integration of microalgal hydrogen synthesis with other renewable energy sources. The potential for microalgal hydrogen generation is considered pivotal in transitioning toward a future reliant on more renewable and sustainable energy sources. This review aims to serve as a valuable resource for researchers, decision-makers, and anyone interested in the advancement of environmentally conscious energy technology. The primary objective of this research paper is to scrutinize the challenges, opportunities, and potential outcomes associated with eco-friendly bio-hydrogen production through algae. It evaluates the current technological hurdles facing bio-hydrogen synthesis from algae. Graphical Highlights: Interest in developing renewable fuels, such as hydrogen from biomass, has surged due to escalating energy demands and the imperative to curtail greenhouse gas emissions. Overview of bio-hydrogen production pathway, reactor designs, and configurations for bio-hydrogen production from bio-algae were explored. Environmental, social sustainability and economic feasibility have been reviewed. Discussion: Will bio-hydrogen from bio-algae be a future renewable energy? Which is the best pathway to produce bio-hydrogen from bio-algae? Regarding greenhouse gas emissions, how does the generation of bio-hydrogen from bio-algae compare to conventional hydrogen production techniques? What difficulties lie in increasing the amount of bio-hydrogen produced by bio-algae to satisfy major energy demands?

The present research focuses on synthesizing surface-modified egg shell powders using ultrasonic modification method for the effective adsorption of malachite green dye (MG). The presence of functional groups and surface morphology of ultrasonic-assisted egg shell powder (UAESP) was characterized using Fourier transform infrared spectrophotometer (FTIR) and scanning electron microscopy (SEM) analysis, respectively. A batch adsorption study was performed to predict the optimum conditions, and the results showed that maximum adsorption rate at the solution pH of 8.0 within the interaction time of 90 min, dosage of 1.5 g/L for MG dye concentration of 25 mg/L, and temperature 30°C. The isotherm and kinetics modeling of the present adsorption system can be well described by Freundlich and pseudosecond-order kinetics, respectively. The monolayer adsorption capacity of UAESP for MG dye was originated to be 64.58 mg/g. The results of the thermodynamic study reported that adsorption removal of MG dye onto UAESP was exothermic and spontaneous. This study accredited that UAESP has higher efficiency, cost-effective, and sustainable adsorbent for the removal of hazardous dyes on an industrial level.

This research explores the adsorption (AD) of diclofenac sodium (DS) onto a Hydrothermally produced activated carbon impregnated with ZnO (HTC‐AC/ZnO) surface, considering various factors such as initial concentration (IC), adsorbent dose, contact time, and pH. The characterization of HTC‐AC/ZnO was performed using X‐ray diffractometer (XRD), scanning electron microscope (SEM), Fourier‐transform infrared spectroscopy (FTIR), and nitrogen physisorption spectroscopy (BET). Tests were conducted with different adsorbent doses (0.5–4 g/L) at 303 K and various initial diclofenac concentrations (ranging from 50 mg/L to 250 mg/L) to observe their effects. Additionally, pH values were altered from 2 to 12 to study their influence on AD. Kinetic studies, thermodynamic studies, and AD isotherm models were examined. The Temkin isotherm model (TIM) was found to be the most accurate for DS‐AD on HTC‐AC/ZnO. For DS‐AD on HTC‐AC/ZnO, pseudo‐first‐order models (PFOM), intraparticle diffusion model (IPDM), and pseudo‐second‐order models (PSOM) were applied, with a correlation coefficient of 0.945, indicating a good fit for PFOM. The kinetics suggested rapid adsorption. Notably, the HTC‐AC/ZnO composite exhibited consistent AD characteristics across four consecutive cycles, with a removal efficiency exceeding 99.38%. This suggests that HTC‐AC/ZnO is an appropriate and economically viable adsorbent for the elimination of DS from water‐based solutions. The investigation provides compelling evidence that HTC‐AC/ZnO is a viable adsorbent for the effective elimination of DS from water sources.

This study examined the use of Kigelia Africana peel-activated carbon (KAP-AC) to remove ciprofloxacin (CIP) from aqueous solutions. To investigate the adsorption capacity, isotherm, and kinetic parameters of the adsorption process, batch adsorption experiments were conducted to test the effects of adsorbent dosage, time, pH, initial concentration of CIP, and temperature. The binding mechanism among KAP-AC and CIP was investigated using FTIR, XRD, and SEM. Models of the Langmuir adsorption isotherm (LAI), Freundlich adsorption isotherm (FAI), and Temkin adsorption isotherm (TAI) helped to clarify the adsorption process. Adsorption experiments were carried out to explain kinetic studies, such as the pseudo-first-order kinetic model (PFO-KM), pseudo-second-order kinetic model (PSO-KM), and intraparticle diffusion kinetic model (IPD-KM). The experimental results may be more accurately described by the FAI and PFO-KM. Additionally, response surface methodology (RSM), which is based on Box–Behnken (BB) surface statistical design, was used to investigate the impact of variables on the adsorption of CIP. Higher coefficients of correlation and p-value values, by BB design, were in excellent adaption with the ideal combination of process variables, indicating the suitability of the selected model for assessing the experimental data.