Presently, hazardous metal and dye removal from wastewater is one of the major areas of research focus. For the elimination of these contaminants, many approaches have been devised and applied. However, the accomplishment of various water treatment processes has largely depended on the medium utilized and the associated problem with the leaching of harmful compounds into the water process with most commercial and chemically manufactured materials for water treatment processes. Hence, this study is aimed at reviewing existing studies on the sorption of heavy metals (HMs) and dyes using bionanocomposites (BNCs). The key focus of this review is on the development of eco-friendly, effective, and appropriate nanoadsorbents that could accomplish superior and enhanced contaminant sequestration using BNCs owing to their biodegradability, biocompatible, environmentally friendly, and not posing as secondary waste to the environment. The sorption of most pollutants was observed to be pH, sorbent dosage, and initial contaminant concentration-dependent, with most contaminants’ elimination taking place in the pH range of 2-10. The sorption process of HMs and dyes to various BNCs was superlatively depicted utilizing the Langmuir (LNR) and Freundlich (FL) as well as the pseudo-second-order (PSO) models, suggestive of the sorption process of a monolayer and multilayer and the chemisorption process, the rate-limiting stage in surface sorption. The established sorption capacities for the reviewed sorption process for various contaminants ranged from 1.47 to 740.97 mg/g. Future prospective for the treatment and remediation of contaminated water using BNCs was also discussed.

Several agronomic waste-materials are presently being widely used as bio-adsorbents for the treatment of toxic wastes such as dyes and heavy metals from industrial activities, which has resulted in critical global environmental issues. Therefore, there is a need to continue searching for more effective means of mitigating these industrial effluents. Synthetic aromatic dyes such as Acid Brown (AB14) dye are one such industrial effluent that is causing a serious global issue owing to the huge amount of these unsafe effluents released into the ecosystem daily as contaminants. Consequently, their confiscation from the environment is critical. Hence, in this study, Mandarin-CO-TETA (MCT) derived from mandarin peels was utilized for the removal of AB14 dyes. The synthesized biosorbent was subsequently characterized employing FTIR, TGA, BET, and SEM coupled with an EDX. The biosorption of this dye was observed to be pH-dependent, with the optimum removal of this dye being noticed at pH 1.5 and was ascribed to the electrostatic interaction between the positively charged sites on the biosorbent and the anionic AB14 dye. The biosorption process of AB14 dye was ideally described by employing the pseudo-second-order (PSO) and the Langmuir (LNR) models. The ideal biosorption capacity was calculated to be 416.67 mg/g and the biosorption process was indicative of monolayer sorption of AB14 dye to MCT biosorbent. Thus, the studied biosorbent can be employed as a low-cost activated biomass-based biosorbent for the treatment of AB14 dyes from industrial activities before they are further released into the environment, thus mitigating environmental contamination.

Gas flaring (GasF) is an important aspect of the combustion mechanisms in the burning of related, undesirable, or surplus fluids (gases in particular) that are released during the ordinary or unexpected overpressuring process in several industrial activities, specifically in the petroleum resource (PTR) industries. It is also one of the major sources of greenhouse gas emissions which cause climate change (CMC). In addition to the generation of noise and heat, it makes substantial adjacent areas uninhabitable and, hence, causes detrimental consequences to the entire ecosystem as well as waste energy and results in economic losses. Reducing GasF is a critical issue due to its ensuing complications; consequently, there is a tenacious need to measure GasF via the study of its composition, distribution, and capacity, as well as the utilization of appropriate GasF recovery/removal procedures. The present review study will, thus, attempt to assess the impacts of GasF on the environment vis-à-vis the possible nexus between GasF/CMC using the perspective of the Niger Delta region of Nigeria which is rich in PTR, with relevant information drawn from existing publications. The roles of government, policymakers, and relevant stakeholders as well as suggestions and recommendations that will assist in the extenuation approaches and technologies of the influence of GasF on the environment are also discussed.