The synthesis and application of porphyrins has seen a huge shift towards research in porphyrin bio-molecular based systems in the past decade. The preferential localization of porphyrins in tumors, as well as their ability to generate reactive singlet oxygen and low dark toxicities has resulted in their use in therapeutic applications such as photodynamic therapy. However, their inherent lack of bio-distribution due to water insolubility has shifted research into porphyrin-nanomaterial conjugated systems to address this challenge. This has broadened their bio-applications, viz. bio-sensors, fluorescence tracking, in vivo magnetic resonance imaging (MRI), and positron emission tomography (PET)/CT imaging to photo-immuno-therapy just to highlight a few. This paper reviews the unique theranostic role of porphyrins in disease diagnosis and therapy. The review highlights porphyrin conjugated systems and their applications. The review ends by bringing current challenges and future perspectives of porphyrin based conjugated systems and their respective applications into light.

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In this study, nano iron (nano-Fe) was successfully synthesized by sodium borohydride reduction of ferric chloride solution to enhance the ultrasonic degradation of phenolsulfonphthalein (PSP). The nano-Fe was characterized by scanning electron microscopy - energy dispersive spectroscopy (SEM-EDX), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), attenuated total reflection - Fourier transform infrared spectroscopy (ATR-FTIR), and Brunauer, Emmett and Teller (BET) surface area determination. Experimental results demonstrated that a combined ultrasonic/nano-Fe/HO system was more effective for PSP removal in combination than they were individually and there was a significant difference between the combined and single processes. The ultrasonic/nano-Fe/HO degradation follows the Langmuir-Hinshelwood (L-H) kinetic model. The addition of nano-Fe and HO to the ultrasonic reactor greatly accelerated the degradation of PSP (25 mg/L) from 12.5% up to 96.5%. These findings indicated that ultrasonic degradation in the presence of nano-Fe and HO is a promising and efficient technique for the elimination of emerging micropollutants from aqueous solution.

Membrane separation processes tender a capable option for energy-demanding separation processes. Nanofiltration (NF) and reverse osmosis (RO) membranes are among the most explored, with a latent use in the chemical industry. In this study, four commercial membranes (NF90, NF270, BW30, and XLE) were investigated for their applicability based on the key structural performance characteristics in the recycling of Pd-based catalysts from Heck coupling post-reaction mixture. Pure water and organic solvent permeabilities, uncharged solute permeability, swelling, and catalyst rejection studies of the membranes were conducted as well as the morphological characterization using Fourier transform infrared, field emission gun scanning electron microscopy, and atomic force microscopy. Characterization results showed trends consistent with the manufactures’ specifications. Pure water and organic solvent fluxes generally followed the trend NF270 > NF90 > BW30 > XLE, with the solvent choice playing a major role in the separation process. Pd(PPh3)2Cl2 was well rejected by almost all membranes in 2-propanol; however, XLE rejects Pd(OAc)2 better at high pressure in acetonitrile. Our study, therefore, revealed that the separation and reuse of the two catalysts by NF90 at 10 bar resulted in 97% and 49% product yields with 52% and 10% catalyst retention for Pd(OAc)2 while Pd(PPh3)2Cl2. gave 87% and 6% yields with 58% and 36% catalyst retention in the first and second cycles, respectively. Considering, the influence of membrane–solute interactions in Pd-catalyst rejection, a careful selection of the polymeric membrane and solvent, a satisfactory separation, and recovery can be achieved.

In this study, a magnetic generation-5 polyamidoamine (G-5 PAMAM) dendrimer-functionalized SBA-15 (mPSBA) composite was synthesized by coupling amine-functionalized silica (SBA-15-NH 2 ) and amine-functionalized magnetic nanoparticles (MNP-NH 2 ) with the G-5 PAMAM, before characterization and aqueous sorption of As(III), Cd(II), tetracycline, and ciprofloxacin using the composite. The mPSBA characterization data exhibited the typical Si−O−Si infrared peaks from the SBA-15 backbone in addition to the acquired characteristic infrared Fe−O and amide-I/II peaks from the MNP and G-5 PAMAM dendrimers, respectively. Postsorption infrared spectra showing shifts for the amide-linked groups indicated the likely points of contaminant attachment on the composite. Its thermal stability was lower than that of SBA-15 but higher than that of SBA-15-NH, while the XRD diffractograms of the backbone SBA-15-NH and MNP were unchanged in the final composite. The mPSBA composite was a better As(III) and Cd(II) adsorbent than SBA-15 by ≈400 and 140%, respectively, with rapid uptake in the first 60 min and equilibrium achieved at 120 min. Sorption was enhanced with increasing pH (until pHpzc) and initial contaminant concentration. The process was spontaneous and endothermic; thus, increasing ambient temperature enhanced Cd(II) sorption. The sorption data fitted better to the homogeneous fractal pseudo-second-order (FPSO) kinetics model and the Brouers−Sotolongo fractal adsorption isotherm models, indicating complex sorption interactions and pore-filling/contaminant trapping within mPSBA. Further experiments using mPSBA for the uptake of tetracycline and ciprofloxacin showed 679% and 325% higher sorption, respectively, compared with that for SBA-15-NH. In addition to the added advantage of easy removal from solution/treated water after the adsorption process, mPSBA sorption capacities for these studied contaminants [As(III): 23.3 mg/g; Cd(II): 74.5 mg/g; tetracycline: 38.4 mg/g; ciprofloxacin: 23.0 mg/g] are better than those of several advanced adsorbents reported in the literature.