Encompassing all fields of chemical research, BMC Chemistry is an open access, peer reviewed journal that publishes articles on fundamental concepts, new developments and the application of chemical principles to a broad range of research fields, industry, and other disciplines. The journal provides an inclusive platform for the dissemination and discussion of chemistry to aid the advancement of all areas of research. Supported by a highly experienced global Editorial Board, this journal is part of the BMC series, a collection of journals that are focused on individual research communities, publishing all scientifically valid studies based on community-aligned standards of questioning, methods and analysis.

Conversion of nitroaniline (NA), a highly toxic pollutant that has been released into aquatic systems due to unmanaged industrial development in recent years, into the less harmful or a useful counterpart is the need of the hour. Various methods for its conversion and removal have been explored. Owing to its nominal features of advanced effectiveness, the chemical reduction of 4-NA using various different nanocatalytic systems is one such approach that has attracted tremendous interest over the past few years. The academic literature has been confined to case studies involving silver (Ag) and gold (Au) nanoparticles, as these are the two most widely used materials for the synthesis of nanocatalytic assemblies. Focus has also been given to sodium borohydride (NaBH₄), which is used as a reductant during the chemical reduction of NA. This systematic review summarizes the fundamentals associated with the catalytic degradation of 4-NA, and presents a comprehensive and critical study of the latest modifications used in the synthesis of these catalytic systems. In addition, the kinetics, mechanisms, thermodynamics, as well as the future directions required for understanding this model reaction, have been provided in this particular study.

In the present study, Saccharum bengalense (SB), a potential biosorbent, was investigated for the removal of toxic Congo red (CR) dye. The effect of various operating variables, viz. adsorbent dosage, pH, contact time, and temperature on the removal of dye has been studied. Almost 94% removal of dye is possible after 50 min at pH 2.0 under batch test conditions. It was found that a pseudo-second-order mechanism was predominant and the overall rate of the dye adsorption process appears to be controlled by more than one step. The intra-particle diffusion model was applied to investigate the rate determining step. Langmuir, Freundlich, and Dubinin–Radushkevich adsorption isotherm models were applied to describe the biosorption isotherm. The biosorption data were better represented by the Langmuir model and the biosorption capacity (q _max) of SB for CR was achieved at 125 mg/g. Thermodynamic parameters such as standard free energy change (ΔG°), standard enthalpy change (ΔH°), and standard entropy change (ΔS°) were calculated and revealed the spontaneous, endothermic, and feasible nature of the adsorption process. Biomass derived from the pulp of SB was evaluated as an effective biosorbent for removal of CR dye.

In the present study, microwave treated Salvadora oleoides (MW-SO) has been investigated as a potential biosorbent for the removal of toxic methyl violet dye. A batch adsorption method was experimented for biosorptive removal of toxic methyl violet dye from the aqueous solution. The effect of various operating variables, viz., adsorbent dosage, pH, contact time and temperature on the removal of the dye was studied and it was found that nearly 99% removal of the dye was possible under optimum conditions. Kinetic study revealed that a pseudo-second-order mechanism was predominant and the overall process of the dye adsorption involved more than one step. Hence, in order to investigate the rate determining step, intra-particle diffusion model was applied. Adsorption equilibrium study was made by analyzing Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) adsorption isotherm models and the biosorption data was found to be best represented by the Langmuir model. The biosorption efficiency of MW-SO was also compared with unmodified material, Salvadora oleoides (SO). It was found that the sorption capacity (q_max) increased from 58.5 mg/g to 219.7 mg/g on MW treatment. Determination of thermodynamic parameters such as free energy change (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°) confirmed the spontaneous, endothermic and feasible nature of the adsorption process. The preparation of MW-SO did not require any additional chemical treatment and a high percentage removal of methyl violet dye was obtained in much lesser time. Thus, it is in agreement with the principles of green chemistry. The results of the present research work suggest that MW-SO can be used as an environmentally friendly and economical alternative biosorbent for the removal of methyl violet dye from aqueous solutions.