Presently, there is increased attention and focus on heavy metals, which are becoming one of the most serious environmental problems due to their adverse health effects. These toxic heavy metals are not easily degraded and require removal from polluted water to protect people and the environment. The purpose of this work was to prepare two types of dithiocarbamate ligands, one aliphatic (diethyldithiocarbamate) and the other aromatic (diphenyldithiocarbamate), and to use them as chelators to remove Pb, Cd, Cu and Zn from polluted water. Dithiocarbamates were selected because they have good binding ability and can precipitate metal ions as complexes. The metal removal efficiency is compared between both ligands and also compared to the efficiency of activated carbon in an adsorption process to remove the same metals. The investigation results indicated that the diphenyldithiocarbamate ligand was more efficient in removing the studied metals than the diethyldithiocarbamate analogues. Additionally, the metal removal efficiency of the diphenyldithiocarbamate ligand was more effective than using the activated carbon method

This investigation aimed at evaluating the efficiency of micro and nanoclays as a low-cost material for the removal of crystal violet (CV) dye from an aqueous solution. The impacts of various factors (contact time, pH, adsorbent dosage, temperature, initial dye concentration) on the adsorption process have been taken into consideration. Six micro and nanoclay samples were obtained by treating clay materials collected from different locations in the Albaha region, Saudi Arabia. Out of the six tested micro and nanoclays materials, two (NCQ1 and NCQ3) were selected based on the highest adsorption efficiency for complete experimentation. The morphology and structure of the selected micro and nanoclay adsorbents were characterized by various techniques: SEM-EDX, FTIR, XRF, XRD, and ICP-MS. The XRF showed that the main oxides of both nanoclays were SiO₂, Al₂O₃, Fe₂O₃, K₂O, CaO, and MgO, and the rest were impurities. All the parameters affecting the adsorption of CV dye were optimized in a batch system, and the optimized working conditions were an equilibrium time of 120 min, a dose of 30 mg, a temperature of 25 °C, and an initial CV concentration of 400 mg/L. The equilibrium data were tested using nonlinear isotherm and kinetic models, which showed that the Freundlich isotherm and pseudo-second-order kinetics gave the best fit with the experimental data, indicating a physico-chemical interaction occurred between the CV dye and both selected micro and nanoclay surfaces. The maximum adsorption capacities of NCQ1 and NCQ3 adsorbents were 206.73 and 203.66 mg/g, respectively, at 25 °C. The thermodynamic factors revealed that the CV dye adsorption of both micro and nanoclays was spontaneous and showed an exothermic process. Therefore, the examined natural micro and nanoclays adsorbents are promising effective adsorbents for the elimination of CV dye from an aqueous environment.

In this paper, a Schiff base ligand 1-(2-thiophenylimino)-4-(N-dimethyl)benzene (SL₁) bearing azomethine (>C=N-) and thiol (-SH) moieties capable of coordinating to metals and forming colored metal complexes was synthesized and examined as a colorimetric chemosensor. The sensing ability toward the metal ions of Cu²⁺, Cr³⁺, Fe²⁺ Ni²⁺, Co²⁺, Mg²⁺, Zn²⁺, Fe²⁺, Fe³⁺, NH₄VO₃ (V⁵⁺), Mn²⁺, Hg²⁺, Pb²⁺, and Al³⁺ was investigated in a mixture of H₂O and dimethylformamide (DMF) solvent using the UV–Visible spectra monitoring method. The synthesized Schiff base ligand showed colorimetric properties with Cr³⁺, Fe²⁺, Fe³⁺, and Hg²⁺ ions, resulting in a different color change for each metal that could be identified easily with the naked eye. The UV–Vis spectra indicated a significant red shift (~69–288 nm) from the origin after the addition of the ligand to these metal ions, which may be due to ligand-to-metal charge-transfer (LMCT). On applying Job’s plot, it was indicated that the ligand binds to the metal ions in a 2:1 ligand-to-metal molar ratio. SL₁ behaves as a bidentate ligand and binds through the N atom of the imine group and the S atom of the thiol group. The results indicate that the SL₁ ligand is an appropriate coordination entity and can be developed for use as a chemosensor for the detection of Cr³⁺, Fe²⁺, Fe³⁺, and Hg²⁺ ions.

The purpose of this work was to prepare Schiff base ligands containing quinoline moiety and using them for preparing Cu(ii) and Zn(ii) complexes. Four bidentate Schiff base ligands (SL₁–SL₄) with quinoline hydrazine scaffold and a series of mononuclear Cu(ii) and Zn(ii) complexes were successfully prepared and characterized. The in vitro antibacterial and antifungal potential experimentation revealed that the ligands exhibited moderate antibacterial activity against the Gram-positive bacterial types and were inactive against the Gram-negative bacteria and the fungus strains. The metal complexes showed some enhancement in the activity against the Gram-positive bacterial strains and were inactive against the Gram-negative bacteria and the fungus strains similar to the parent ligands. The complex [Cu(SL₁)₂] was the most toxic compound against both Gram-positive S. aureus and E. faecalis bacteria. The in silico physicochemical investigation revealed that the ligand SL₄ showed highest in silico absorption (82.61%) and the two complexes [Cu(SL₄)₂] and [Zn(SL₄)₂] showed highest in silico absorption with 56.23% for both compounds. The in silico pharmacokinetics predictions showed that the ligands have high gastrointestinal (GI) absorption and the complexes showed low GI absorption. The ligands showed a good bioavailability score of 0.55 where the complexes showed moderate to poor bioavailability.

Sediments are the ultimate sump for heavy metal pollutants. The main purpose was to investigate the ecological and health risk assessment of heavy metals in the sediments of Wadi Al-Aqiq water reservoir. The metals detected were arranged in decreasing order Fe > Mn > Cr > Cu > Zn > Ni > Co > Pb. Pearson correlation analysis indicated strong positive association and significant linear relation between various pairs of metals. Different evaluation indices used indicated that source of contamination from lithogenic sources and sediments can be classified as low polluted quality. A comparison of the concentrations of metals with International Sediment Quality Guidelines criteria showed that only Cu and Ni concentrations above the ERL and below the ERM guideline values suggest possible adverse effects. On comparing with US Environmental Protection Agency prepared sediment quality criteria it indicated that Pb and Zn have concentrations below the non-polluted criteria, Fe, Mn, and Ni lies in the range of moderately polluted criteria, and Co and Cu are within the heavily polluted criteria. Non-carcinogenic risk quantification indicated health concern from ingestion route and no health effects for dermal exposure. On considering additive effect, the dermal exposure may cause health harm. The carcinogenic risk assessment for lead and chromium showed an acceptable risk to human health.

The documentation of ethnobotanical knowledge is useful for biocultural conservation, preserving the diversity of plants, and drug development. The present study was carried out to compile and document the knowledge and uses of plants in Al Baha Province, Kingdom of Saudi Arabia (KSA). A total of 81 knowledgeable informants of different sexes, ages, and status levels were randomly selected and interviewed. The majority of the informants (63%) were > 60 years old. The collected data were qualitatively and quantitatively described using different quantitative indices [family importance value (FIV), use value (UV), and informant consensus factor (ICF)]. The fidelity level (FL), rank order priority (ROP), and relative popularity level (RPL) were determined for the plants (42 species) mentioned by at least three informants. A total of 97 plants belonging to 91 genera and 44 families were reported. The most commonly used parts were fruits (30.7%) and leaves (25.4%), whereas the most frequently used modes of preparation were maceration (24.7%) and direct application (23.3%). Most of the cited plants (49.5%) were traditionally used for gastrointestinal tract (GIT) disorders, whereas a few plants (6.2%) were used for the treatment of reproductive disorders. The most ethnobotanically important families were Lamiaceae (FIV = 0.35) and Apiaceae (FIV = 0.33). The highest UV was represented by Zingiber officinale (0.086) followed by Commiphora myrrha and Trigonella foenum-graecum (0.074). The level of agreement among the interviewees was remarkably high (ICF = 0.65–0.93) for plants that had the ability to cure infectious diseases. A low level of agreement (ICF = 0.33–0.48) was observed among the informants towards plants that were used to treat gastrointestinal tract, reproductive, hematological, and central nervous system disorders. There was a total and absolute disagreement (ICF = 0) among the informants regarding the plants that were used to treat renal, endocrine system, oncological/immunological, rheumatic, orthopedic, ear, nose, and throat (ENT), and inflammatory disorders. Six of the plants which were cited by three informants or more had a high healing efficacy (FL = 100) and forty species attained ROP values of 50 or above. Out of the 42 plants, 20 species were grouped as popular (RPL = 1), and the remaining plants (22 species) were unpopular (RPL < 1). Curcuma longa, which showed the highest ROP value (100), was used to enhance immunity. In conclusion, various plant species in Al Baha province were used by the local communities for the treatment of different health problems. The documentation of these plants could serve as a basis for further scientific research and conservation studies.